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https://issues.apache.org/jira/browse/ZOOKEEPER-1366?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13759315#comment-13759315
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Asad Saeed commented on ZOOKEEPER-1366:
---------------------------------------
A few issues with this patch. It is much broader than it should be.
In Login.java: 2 timesources are being utilized and incorrectly compared:
Time.currentElapsedTime is not compatible with the (KerberosTicket).getEndTime
which will return the expiry based on the system time. The 2 time values are
compared in the following block
--
if (nextRefresh > expiry) {
LOG.error("next refresh: " + nextRefreshDate + " is
later than expiry " + expiryDate
+ ". This may indicate a clock skew
problem. Check that this host and the KDC's "
+ "hosts' clocks are in sync. Exiting
refresh thread.");
return;
--
ZookeeperServer::getTime: Utilization of Time.currentElapsedTime here will lead
to unusable timestamps for the mtime and ctime for nodes. DataTree::processTxn
uses the TxnHeader.time to populate the Stat structure. TxnHeader.time is
assigned by PrepRequestProcessor::pRequest2Txn using ZookeeperServer.getTime.
> Zookeeper should be tolerant of clock adjustments
> -------------------------------------------------
>
> Key: ZOOKEEPER-1366
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-1366
> Project: ZooKeeper
> Issue Type: Bug
> Reporter: Ted Dunning
> Assignee: Ted Dunning
> Fix For: 3.5.0
>
> Attachments: ZOOKEEPER-1366-3.3.3.patch, ZOOKEEPER-1366.patch,
> ZOOKEEPER-1366.patch, ZOOKEEPER-1366.patch, ZOOKEEPER-1366.patch,
> ZOOKEEPER-1366.patch, ZOOKEEPER-1366.patch, ZOOKEEPER-1366.patch,
> zookeeper-3.4.5-ZK1366-SC01.patch
>
>
> If you want to wreak havoc on a ZK based system just do [date -s "+1hour"]
> and watch the mayhem as all sessions expire at once.
> This shouldn't happen. Zookeeper could easily know handle elapsed times as
> elapsed times rather than as differences between absolute times. The
> absolute times are subject to adjustment when the clock is set while a timer
> is not subject to this problem. In Java, System.currentTimeMillis() gives
> you absolute time while System.nanoTime() gives you time based on a timer
> from an arbitrary epoch.
> I have done this and have been running tests now for some tens of minutes
> with no failures. I will set up a test machine to redo the build again on
> Ubuntu and post a patch here for discussion.
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