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https://issues.apache.org/jira/browse/WHIRR-128?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Tom White updated WHIRR-128:
----------------------------
Resolution: Fixed
Status: Resolved (was: Patch Available)
I've just committed this. Thanks Tibor!
(BTW you don't need to delete old attachments. In fact, it's good to leave them
so that folks can see the progression of development.)
> In ec2 instances instead of public dns names a public ip address is resolved
> for the started master node which causes workers to not be able to connect
> back to the master
> --------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: WHIRR-128
> URL: https://issues.apache.org/jira/browse/WHIRR-128
> Project: Whirr
> Issue Type: Bug
> Components: core
> Affects Versions: 0.3.0
> Environment: Running hadoop (apache or CDH distro) in ec2 instances
> (Ubuntu or CentOS or Fedora).
> The same issue with the integration test of whirr.
> Reporter: Tibor Kiss
> Assignee: Tibor Kiss
> Fix For: 0.3.0
>
> Attachments: compare-myhost-with-ec2.txt, on-ec2-after-patch.tar.gz,
> on-ec2-before-patch.tar.gz, whirr-trunk.patch
>
>
> The problem it is related to the nature how it is resolved the reverse
> address in ec2 instances.
> After isolating the problem I could write a very simple app which reproduces
> the cause of the issue.
> Pass in args the public ip address of the ec2 instance where are you running
> the following small code.
> InetAddress namenodePublicAddress = InetAddress.getByName(args[0]);
> System.out.println("getHostAddress: " +
> namenodePublicAddress.getHostAddress());
> System.out.println("getHostName: " + namenodePublicAddress.getHostName());
> System.out.println("getCanonicalHostName: " +
> namenodePublicAddress.getCanonicalHostName());
> If I am running it on my laptop I get
> getHostAddress: 50.16.71.64
> getHostName: ec2-50-16-71-64.compute-1.amazonaws.com
> getCanonicalHostName: ec2-50-16-71-64.compute-1.amazonaws.com
> if I am running it on ec2 instance
> getHostAddress: 50.16.71.64
> getHostName: 50.16.71.64
> getCanonicalHostName: 50.16.71.64
> My laptop has the same CentOS 5.5 as my ec2 instance and the /etc/resolv.conf
> in each cases contains a nameserver entry.
> For some unknown reason, the java.net.InetAddress's getHostName() or
> getCanonicalHostName() does not resolves reverse dns names for ec2 public
> addresses if it was running in ec2 instance.
> But any other resolver tools correctly resolves that reverse dns name.
> In whirr codebase there are some getHostName() calls, which because of the
> previously described symptom, causes that /etc/hadoop/conf/hadoop-site.xml on
> the worker nodes are incorrectly filled with ip addresses instead of dns
> names. As we know, it is important to use public dns name of the ec2 instance
> because amazon's nameserver it can resolve to an external or internal ip
> address, one that is better for direct communication. In case of hadoop
> cluster, the used security group does not allow intercommunication between
> nodes by using public ip address and therefore the worker nodes cannot
> contact the services on the master node. Looking into the hadoop logs it is
> clearly visible the problem that workers cannot connect to master.
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