[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12934695#action_12934695 ] Hadoop QA commented on ZOOKEEPER-702: - -1 overall. Here are the results of testing the latest attachment http://issues.apache.org/jira/secure/attachment/12460193/ZOOKEEPER-702.patch against trunk revision 1036967. +1 @author. The patch does not contain any @author tags. +1 tests included. The patch appears to include 72 new or modified tests. +1 javadoc. The javadoc tool did not generate any warning messages. +1 javac. The applied patch does not increase the total number of javac compiler warnings. -1 findbugs. The patch appears to introduce 14 new Findbugs (version 1.3.9) warnings. +1 release audit. The applied patch does not increase the total number of release audit warnings. -1 core tests. The patch failed core unit tests. +1 contrib tests. The patch passed contrib unit tests. Test results: https://hudson.apache.org/hudson/job/PreCommit-ZOOKEEPER-Build/48//testReport/ Findbugs warnings: https://hudson.apache.org/hudson/job/PreCommit-ZOOKEEPER-Build/48//artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html Console output: https://hudson.apache.org/hudson/job/PreCommit-ZOOKEEPER-Build/48//console This message is automatically generated. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Fix For: 3.4.0 Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12933307#action_12933307 ] Abmar Barros commented on ZOOKEEPER-702: Thanks for the feedback Flavio. After some investigation, I have noticed that, with the patch applied, the server threads take longer to be released in the tests. I have measured the time that the QuorumPeer.join() invocations take on the QuorumBase.shutdown() method, and it seems that most of the time difference relies on these invocations. However, I am still trying to find out what is causing these threads to be delayed. I need to investigate it further. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Fix For: 3.4.0 Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[
https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12927657#action_12927657
]
Flavio Junqueira commented on ZOOKEEPER-702:
Thanks, Abmar. It looks good to me. I have one quick comment, though. Is there
any configuration value that could be causing tests to run slower? I have the
impression that tests are running slightly slower with your patch. One in
particular that called my attention was QuorumZxidSyncTest:
{noformat}
Trunk: [junit] Running org.apache.zookeeper.test.QuorumZxidSyncTest
[junit] Tests run: 2, Failures: 0, Errors: 0, Time elapsed: 94.55 sec
702: [junit] Running org.apache.zookeeper.test.QuorumZxidSyncTest
[junit] Tests run: 2, Failures: 0, Errors: 0, Time elapsed: 139.985 sec
{noformat}
and this seems to be pretty consistent.
GSoC 2010: Failure Detector Model
-
Key: ZOOKEEPER-702
URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702
Project: Zookeeper
Issue Type: Wish
Reporter: Henry Robinson
Assignee: Abmar Barros
Fix For: 3.4.0
Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt,
chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt,
ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch,
ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch,
ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch,
ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch,
ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch,
ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch,
ZOOKEEPER-702.patch, ZOOKEEPER-702.patch
Failure Detector Module
Possible Mentor
Henry Robinson (henry at apache dot org)
Requirements
Java, some distributed systems knowledge, comfort implementing distributed
systems protocols
Description
ZooKeeper servers detects the failure of other servers and clients by
counting the number of 'ticks' for which it doesn't get a heartbeat from
other machines. This is the 'timeout' method of failure detection and works
very well; however it is possible that it is too aggressive and not easily
tuned for some more unusual ZooKeeper installations (such as in a wide-area
network, or even in a mobile ad-hoc network).
This project would abstract the notion of failure detection to a dedicated
Java module, and implement several failure detectors to compare and contrast
their appropriateness for ZooKeeper. For example, Apache Cassandra uses a
phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which
is much more tunable and has some very interesting properties. This is a
great project if you are interested in distributed algorithms, or want to
help re-factor some of ZooKeeper's internal code.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12915825#action_12915825 ] Flavio Junqueira commented on ZOOKEEPER-702: +1, I'm pretty happy with the patch. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12916021#action_12916021 ] Patrick Hunt commented on ZOOKEEPER-702: Patch applied cleanly for me. I ran the tests and they all passed. I did notice that java test time for me moved from ~18 minutes to ~28 minutes. I don't think we should hold up this patch for this, however going fwd we should think about how to enable a quicker commit test (run by devs before submitting/committing) as well as longer running hudson integration tests. Where the commit test runs more quickly (hopefully 10minutes). We will probably need to use something like junit test category support. Nice job, thanks. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12915034#action_12915034 ] Flavio Junqueira commented on ZOOKEEPER-702: In the previous comment, hopefully it was clear that I meant to say that the new tests are NOT working as expected. Apologies for the typo. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12913629#action_12913629 ] Ivan Kelly commented on ZOOKEEPER-702: -- I thought I had replied to your comment on the 13th, but it seems not. Looking at the code again, the way you did the factory is good. I misunderstood how zookeeper handled configuration. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12913669#action_12913669 ] Ivan Kelly commented on ZOOKEEPER-702: -- +1 GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[
https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12908817#action_12908817
]
Ivan Kelly commented on ZOOKEEPER-702:
--
Code looks good Ambar, good job :)
I think the factory code could be improved slightly though. Currently if you
want a custom FD you pass in a FDname and an FDClass.
I would merge these two, so that you only pass in FDname to the factory, and
the factory can decide whether this is a builtin or a custom. So as an example,
FDname can be fixed, chen, phiaccrual or com.blah.foobar.MyFailureDetector.
When the factory sees this it goes...
if (fdName.equals(fixed)) {
fdClass = FixedPingFailureDetector.class;
} else if (fdName.equals(chen)) {
fdClass = ChenFailureDetector.class;
} else if (fdName.equals(bertier)) {
fdClass = BertierFailureDetector.class;
} else if (fdName.equals(phiaccrual)) {
fdClass = PhiAccrualFailureDetector.class;
} else if (fdName.equals(sliced)) {
fdClass = SlicedPingFailureDetector.class;
} else {
fdClass = Class.forName(fdName);
}
GSoC 2010: Failure Detector Model
-
Key: ZOOKEEPER-702
URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702
Project: Zookeeper
Issue Type: Wish
Reporter: Henry Robinson
Assignee: Abmar Barros
Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt,
chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt,
ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch,
ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch,
ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch,
ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch,
ZOOKEEPER-702.patch, ZOOKEEPER-702.patch
Failure Detector Module
Possible Mentor
Henry Robinson (henry at apache dot org)
Requirements
Java, some distributed systems knowledge, comfort implementing distributed
systems protocols
Description
ZooKeeper servers detects the failure of other servers and clients by
counting the number of 'ticks' for which it doesn't get a heartbeat from
other machines. This is the 'timeout' method of failure detection and works
very well; however it is possible that it is too aggressive and not easily
tuned for some more unusual ZooKeeper installations (such as in a wide-area
network, or even in a mobile ad-hoc network).
This project would abstract the notion of failure detection to a dedicated
Java module, and implement several failure detectors to compare and contrast
their appropriateness for ZooKeeper. For example, Apache Cassandra uses a
phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which
is much more tunable and has some very interesting properties. This is a
great project if you are interested in distributed algorithms, or want to
help re-factor some of ZooKeeper's internal code.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12908876#action_12908876 ] Abmar Barros commented on ZOOKEEPER-702: Hi Ivan, thanks for the feedback. I thought the idea was to declare an alias to a custom failure detector, so setting its options would be more user friendly. e.g.: sessionsFD = myfd sessionsFD.myfd = com.softwaresoft.zk.myFailureDetector sessionsFD.myfd.blahblah = foobar sessionsFD.myfd.myoption = barfoo In this case, I need both className and fdName parameters in the factory code (and this is how it is implemented in the patch). What do you think? GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12909119#action_12909119 ] Flavio Junqueira commented on ZOOKEEPER-702: Hi Abmar, I believe my comments from Aug 18 have not been addressed. In particular, I still see the same javadoc issues and no test exercising the failure detectors with a running ensemble. I believe the default failure detector is naturally exercised in various tests, but it would be good to have tests that also exercise the other failure detectors in a running ensemble. Isn't it right? There are still several references in javadocs and in the documentation to heartbeat. Should we replace them with ping for consistency? I'm also seeing some tests failing, like ObserverTest and NioNettySuiteHammerTest, but I'm not sure if this is related to this patch. I will explore a little further. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12904620#action_12904620 ] Flavio Junqueira commented on ZOOKEEPER-702: +1 to changing the API to use either ping or heartbeat only. I prefer ping because it is shorter. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12904247#action_12904247 ] Ivan Kelly commented on ZOOKEEPER-702: -- I think putting it under the fd.classname would be most accessible for users. For example, fd.myfailuredetector = com.softwaresoft.zk.myFailureDetector fd.myfailuredetector.blahblah = foobar fd.myfailuredetector.myoption = barfoo etc... Then when the factory tries to instantiate a myfailuredetector and it sees that myfailuredetector isn't a known type it should look up fd. + myfailuredetector in properties, and instantiate the class with fdOptions as a parameter. Let the implementation take care of which options it wants to read from fdOptions. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12904251#action_12904251 ] Ivan Kelly commented on ZOOKEEPER-702: -- One more comment on the API. Ping and heartbeat seem to be used interchangeably though it's my understanding that these are fundamentally the same thing. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12900826#action_12900826 ] Abmar Barros commented on ZOOKEEPER-702: Hi Flavio, As we are using inter arrival times and a flexible sampling window, it can work the same way of Chen's estimation in both cases (j = n or j n). GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12900197#action_12900197 ] Flavio Junqueira commented on ZOOKEEPER-702: Thanks for the comments, Ivan. I particularly agree with your point on building a list every time. I was actually wondering if there is any other important performance penalty we might be introducing. I can't think of any at the moment, but it be good to keep it in mind. The use of hbReceived and appMsgReceived does not bother me because they make more explicit what they do, but I agree it is more flexible the way you propose. Abmar, I went back to the papers and contrasted your implementation against the proposed algorithms. The only issue I could find is that the Bertier approach computes EA differently when j n. I suggest we follow their description. The others seem fine to me. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12899765#action_12899765 ] Flavio Junqueira commented on ZOOKEEPER-702: Great job so far, Abmar. I'm thoroughly reviewing the patch, and I'm not done yet, but I have I few comments that you could consider addressing: # Please revise javadocs. Many of them have typos and incorrect information, e.g., the phi accrual javadocs refer to the Bertier fd; # In ZooKeeperMain.java (-259,9 +279,21), you should perhaps have a more informative message when throwing an IllegalArgumentException. You could, for example, list the current fd options available; # The tests included do not exercise the failure detectors with a running instance of the system. Instead they only check a few invariants of the failure detectors. We need to test that we can run an ensemble of servers with each of the failure detector implementations. You could use (or extend if necessary) QuorumBase or QuorumUtil to run an ensemble with each of the failure detectors. You could then kill the leader while executing operations and verify that eventually a new leader emerges and regular operation is resumed. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12899806#action_12899806 ] Ivan Kelly commented on ZOOKEEPER-702: -- Hi Abmar, The code looks good. Excellent job! I have a few comments about the API. API: Ping and Heartbeat are used interchangably. There are heartbeatReceived appMessageReceived and pingSent appMessageSent. In the actual implementations these do the same or very similar things. It would make sense to compress them into one api, and have the type of message received/sent specified by a parameters. Whats more, if a new type of message comes along, the failure detectors will already handle it without each needing to have their code updated. void messageReceived(String id, long now, MessageType type); void messageSent(String id, long now, MessageType type); The getFailedObjects and getObjectsToPing are used to return lists, which in all but one case have contains called on them once and are then discarded. I think these would be better as: bool isFailed(String id, long now) bool shouldPing(String id, long now) So that: a) You don't construct a list which is going to be discarded very soon. b) The internals of the FailureDetector are better hidden from the user of the API. In fact, shouldPing could be discarded and getTimeToNextPing(String id, long now) == 0 used. release should be releaseMonitored to make it symmetrical with registerMonitored. General: The failure detection factory could use newInstance to create arbitary failure detectors. So after if (fdName.equals(slicedhb)) fails, you could check if fdName is a fully qualified class name, and if so find the class and create a newInstance. This way its possible to add a failure detector without having to modify the zookeeper code. There's a lot of duplication in the javadoc for the Zookeeper class. A lot of this could be eliminated by using the @see directive. FailureDetector.java L131, typo, pint instead of ping. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12899443#action_12899443 ] Ivan Kelly commented on ZOOKEEPER-702: -- I've just attempted to apply ZOOKEEPER-702.patch against trunk and it doesn't works. The patch seems to be a delta against a previous patch. Could you generate a patch of everything against current trunk? GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12899447#action_12899447 ] Ivan Kelly commented on ZOOKEEPER-702: -- Ignore that, something strange happened when I downloaded. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12899105#action_12899105 ] Abmar Barros commented on ZOOKEEPER-702: I have updated the wiki page with the results of the experiments: http://wiki.apache.org/hadoop/ZooKeeper/GSoCFailureDetector GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12898625#action_12898625 ] Flavio Junqueira commented on ZOOKEEPER-702: Abmar, A few comments: # Unit tests are not running properly for me. It is running very slowly and I'm not sure what's causing it. It looks like you've been running on Windows. It would be good to also test on a Unix platform. I'm on MacOS 10.5.6, Java(TM) SE Runtime Environment (build 1.6.0_20-b02-279-9M3165); # We don't have changes for the C client, right? We need make sure that the documentation says that the C client must currently use the default detector and open a jira to fix it; # Please consider splitting the patch into multiple files to make it easier on other folks to review your work. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12898471#action_12898471 ] Abmar Barros commented on ZOOKEEPER-702: I was thinking of adding a new parameter to the adaptive methods, that is the minimum window size to begin performing timeout adaptation. As we noticed, adaptive methods can get benefit of a large window size, and there can be premature false suspicion if we do not know the behaviour of the network. In this case, the methods will start using a static timeout until the window reaches a certain size. What do you think? GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12893072#action_12893072 ] Abmar Barros commented on ZOOKEEPER-702: Hi Benjamin Thanks for your feedback! Regarding your first question, a failure detector is intended to determine when monitored objects are to be pinged and when they are supposed to have failed. So, you can have two different failure detectors running in two sides of the application, or you can have the failure detector in just one side, and the other side just replies the pings messages. Summarizing, a failure detector implementation is absolutely responsible for one side of the monitoring. Concerning your note, the failure detectors I have implemented rely on the assumption that zk (TCP) guarantees massage delivery and in order. To see the effects of the new failure detection methods, we are planning to do some experiments in the next week. We can also check if there is any effect of TCP in the adaptive fds behavior. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12893137#action_12893137 ] Flavio Junqueira commented on ZOOKEEPER-702: My understanding is that the failure detector is supposed to behave as an oracle that simply says dead or alive for each monitored process. The application on top, in this case ZooKeeper, decides what to do with that information. Followers and leaders will most likely use it differently. Your point about TCP is excellent, Ben.The way I see it the lost packets won't be observed for the failure detector, and they will end up translated into jitter due to the retransmissions, assuming they are retransmitted. Is this right, Abmar? GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12889188#action_12889188 ] Diogo commented on ZOOKEEPER-702: - Hi! There is paper by Satzger et al. where it is described an easy method to use non-periodic application messages as periodic heartbeats. The paper is called A Lazy Monitoring Approach for Heartbeat-Style Failure Detectors. I hope that is still relevant. Cheers, Diogo GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12889280#action_12889280 ] Abmar Barros commented on ZOOKEEPER-702: Hi Diogo! Thank you for indicating this paper, I haven't found such failure detection type so far, it is very interesting. It proposes a simple way of estimating heartbeats arrival times based on application messages. However it does require the attachment of sending times to all application messages (or at least the ones it will use to do the estimation), which is an overhead to message size. Anyway, with the separate failure detector module, it would be easy to implement a new Failure Detector that uses such data. So far, I have adapted the proposed failure detectors in order to compute the estimated next arrival time only when a heartbeat is received. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12888523#action_12888523 ] Abmar Barros commented on ZOOKEEPER-702: As I was refactoring server-to-server monitoring, I noticed that Leaders cannot process the client session heartbeats received by Learners, once they only track the last heartbeat (or app message) received from the clients, in order to report to the Leader (LearnerSessionTracker). I am thinking of tracking the heartbeats (not app messages) received from the clients in the LearnerSessionTracker, so the Learners can send them to the Leader, and the Leader itself can do an adaptive monitoring on these clients too. What do you think? GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12886224#action_12886224 ] Abmar Barros commented on ZOOKEEPER-702: Hi Flavio, actually I was talking about the client monitoring on the server-side (SessionTracking). GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12885159#action_12885159 ] Flavio Paiva Junqueira commented on ZOOKEEPER-702: -- Also, doesn't the leader ping followers at regular intervals? (Leader.java:360) GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12885007#action_12885007 ] Flavio Paiva Junqueira commented on ZOOKEEPER-702: -- Abmar, I'm not sure I understand what you're saying. What exactly prevents you from performing an adaptive monitoring of the clients? If you can use regular intervals, then I would assume that you can also use variable intervals. Is this a problem with our current design or the one we are proposing for this jira? GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12883334#action_12883334 ] Abmar Barros commented on ZOOKEEPER-702: As discussed with Flavio, I am thinking of adding a new parameter called -fd to the client, which will determine the name of the failure detector to be used. In this sense, the parameters of the failure detector will have its name as prefix, for instance: -fd chen -fd.chen.alpha 1 In the server side, these parameters are intended to be defined in the ZooKeeper configuration file. What do you think? GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12882063#action_12882063 ] Abmar Barros commented on ZOOKEEPER-702: Sure Flavio, so it will take another step: * Make failure detector method and parameters configurable by the user. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12881895#action_12881895 ] Flavio Paiva Junqueira commented on ZOOKEEPER-702: -- Three very quick comments, Abmar: 1- Please don't forget to add license headers to each one of the new files; 2- Please add javadocs; 3- I was wondering what the current plan is to configure which failure detector to use and the parameters of the failure detector. In the current patch, it looks like you're setting it directly in the code. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12880618#action_12880618 ] Flavio Paiva Junqueira commented on ZOOKEEPER-702: -- Abmar, It would be nice if you could add some comments to the pseudo-code of each FD, especially for the variables and parameters, and also provide the corresponding references. On your first point above, it would be nice if we could keep using zookeeper messages as heartbeats. On your second point, I believe that the problem you're alluding to will exist in any implementation, since scheduling a message to be sent doesn't guarantee that it will be sent right away. Is there any different issue you're seeing here that I'm overlooking? GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12879450#action_12879450 ] Abmar Barros commented on ZOOKEEPER-702: Once ZooKeeper guarantees delivery order, I can ignore the seq field in heartbeat and pings messages. Now I am implementing the methods on the interface I proposed and two issues came to mind: * ZooKeeper uses application messages as hearbeats, so actual pings and heartbeats are used only at idle states. The proposed methods must be adapted to consider this scenario. * Regarding that a single thread is being used for the app and the FD, there is a delay between the time a monitored must be pinged and the time it is actually pinged. The impact of this delay in the FD QoS must be analyzed. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Attachments: bertier-pseudo.txt, chen-pseudo.txt, phiaccrual-pseudo.txt, ZOOKEEPER-702.patch Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12874163#action_12874163 ] Abmar Barros commented on ZOOKEEPER-702: I have updated the wiki page for this (http://wiki.apache.org/hadoop/ZooKeeper/GSoCFailureDetector), including a discussion on whether there should be another thread for failure detection. I have previously discussed it with Flavio in order to raise benefits and drawbacks of including another thread in the application and we are expecting feedback to make this decision. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Assignee: Abmar Barros Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-702) GSoC 2010: Failure Detector Model
[ https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12855451#action_12855451 ] Patrick Hunt commented on ZOOKEEPER-702: Henry, I'm not seeing the applications on the gsoc site. Can you add me as appropriate? So that I can see the applications I mean. GSoC 2010: Failure Detector Model - Key: ZOOKEEPER-702 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702 Project: Zookeeper Issue Type: Wish Reporter: Henry Robinson Failure Detector Module Possible Mentor Henry Robinson (henry at apache dot org) Requirements Java, some distributed systems knowledge, comfort implementing distributed systems protocols Description ZooKeeper servers detects the failure of other servers and clients by counting the number of 'ticks' for which it doesn't get a heartbeat from other machines. This is the 'timeout' method of failure detection and works very well; however it is possible that it is too aggressive and not easily tuned for some more unusual ZooKeeper installations (such as in a wide-area network, or even in a mobile ad-hoc network). This project would abstract the notion of failure detection to a dedicated Java module, and implement several failure detectors to compare and contrast their appropriateness for ZooKeeper. For example, Apache Cassandra uses a phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which is much more tunable and has some very interesting properties. This is a great project if you are interested in distributed algorithms, or want to help re-factor some of ZooKeeper's internal code. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
