Vishal the attachment seems to be getting removed by the list daemon (I
don't have it), can you create a JIRA and attach? Also this is a good
question for the ppl on zookeeper-user. (ccing)
You are aware that ephemeral znodes are tied to the session? And that
sessions only expire after the session timeout period? At which time any
znodes created during that session are then deleted. The fact that you are
"kill"ing your client process leads me to believe that you are not closing
the session cleanly (meaning that it will eventually expire after the
session timeout period), in which case the ephemeral znodes _should_
reappear when A is restarted and successfully rejoins the cluster. (at least
until the session timeout is exceeded)
On Tue, Oct 5, 2010 at 11:04 AM, Vishal K <vishalm...@gmail.com> wrote:
> I have a 3 node ZK cluster (A, B, C). On one of the the nodes (node A), I
> have a ZK client running that connects to the local server and creates an
> ephemeral znode to indicate clients on other nodes that it is online.
> I have test script that reboots the zookeeper server as well as client on
> A. The test does a getstat on the ephemeral znode created by the client on
> A. I am seeing that the view of znodes on A is different from the other 2
> nodes. I can tell this from the session ID that the client gets after
> reconnecting to the local ZK server.
> So the test is simple:
> - kill zookeeper server and client process
> - wait for a few seconds
> - do zkCli.sh stat ... > test.out
> What I am seeing is that the ephemeral znode with old zxid, time, and
> session ID is reappearing on node A. I have attached the output of 3
> consecutive getstat requests of the test (see client_getstat.out). Notice
> that the third output is the same as the first one. That is, the old
> ephemeral znode reappeared at A. However, both B and C are showing the
> latest znode with correct time, zxid and session ID (output not attached).
> After this point, all following getstat requests on A are showing the old
> znode. Whereas, B and C show the correct znode every time the client on A
> comes online. This is something very perplexing. Earlier I thought this was
> a bug in my client implementation. But the test shows that the ZK server on
> A after reboot is out of sync with rest of the servers.
> The stat command to each server shows that the servers are in sync as far
> as zxid's are concerned (see stat.out). So there is something wrong with A's
> local database that is causing this problem.
> Has anyone seen this before? I will be doing more debugging in the next few
> days. Comments/suggestions for further debugging are welcomed.