Hi Anand, >> We have isolated it to a test setup, where we are able to reproduce this somewhat consistently if we keep a node powered off.
Do you mind share your setup / steps to reproduce if the setup only involves ZooKeeper without other dependencies? On Tue, Oct 11, 2016 at 2:56 PM, Anand Parthasarathy < [email protected]> wrote: > Folks, > > Sending a quick note again to find out if there is any insight the > community can offer in terms of a solution or workaround? We use zookeeper > for service discovery in our product and this issue has surfaced in a large > customer site a couple of times and we need to figure out a solution soon. > > Thanks, > Anand. > > On Mon, Oct 10, 2016 at 10:15 AM, Anand Parthasarathy < > [email protected]> wrote: > > > Folks, > > > > Any insight into this or any workarounds that you can think of to > mitigate > > against this issue? We have isolated it to a test setup, where we are > able > > to reproduce this somewhat consistently if we keep a node powered off. > > > > Thanks, > > Anand. > > > > On Sat, Oct 8, 2016 at 10:05 AM, Anand Parthasarathy < > > [email protected]> wrote: > > > >> Hi Flavio, > >> > >> I have attached the logs from node 1 and node 3. Node 2 was powered off > >> around 10-03 12:36. Leader election kept going until 10-03 15:57:16 > when it > >> finally converged. > >> > >> Thanks, > >> Anand. > >> > >> On Sat, Oct 8, 2016 at 7:55 AM, Flavio Junqueira <[email protected]> > wrote: > >> > >>> Hi Anand, > >>> > >>> I don't understand whether 1 and 3 were able or even trying to connect > >>> to each other. They should be able to elect a leader between them and > make > >>> progress. You might want to upload logs and let us know. > >>> > >>> -Flavio > >>> > >>> > On 08 Oct 2016, at 02:11, Anand Parthasarathy < > >>> [email protected]> wrote: > >>> > > >>> > Hi, > >>> > > >>> > We are currently using zookeeper 3.4.6 version and use a 3 node > >>> solution in > >>> > our system. We see that occasionally, when a node is powered off (in > >>> this > >>> > instance, it was actually a leader node), the remaining two nodes do > >>> not > >>> > form a quorum for a really long time. Looking at the logs, it appears > >>> the > >>> > sequence is as follows: > >>> > - Node 2 is the zookeeper leader > >>> > - Node 2 is powered off > >>> > - Node 1 and Node 3 recognize and start the election > >>> > - Node 3 times out after initLimit * tickTime with "Timeout while > >>> waiting > >>> > for quorum" for Round N > >>> > - Node 1 times out after initLimit * tickTime with "Exception while > >>> trying > >>> > to follow leader" for Round N+1 at the same time. > >>> > - And the process continues where N is sequentially incrementing. > >>> > - This happens for a long time. > >>> > - In one instance, we used tickTime=5000 and initLimit=20 and it took > >>> > around 3.5 hours to converge. > >>> > - In a given round, Node 1 will try connecting to Node 2, gets > >>> connection > >>> > refused waits for notification timeout which increases by 2 every > >>> iteration > >>> > until it hits the initLimit. Connection Refused is because the node 2 > >>> comes > >>> > up after reboot, but zookeeper process is not started (due to a > >>> different > >>> > failure). > >>> > > >>> > It looks similar to ZOOKEEPER-2164 but there it is a connection > timeout > >>> > where Node 2 is not reachable. > >>> > > >>> > Could you pls. share if you have seen this issue and if so, what is > the > >>> > workaround that can be employed in 3.4.6. > >>> > > >>> > Thanks, > >>> > Anand. > >>> > >>> > >> > > > -- Cheers Michael.
