I've tested the patch and let it run 6 days. It did not help, result is still the same. (remaining ZKs form islands based on datacenter they are in).
I have mitigated it by doing a daily rolling restart. Regards, Chris On Mon, Aug 13, 2018 at 2:06 PM Andor Molnar <an...@cloudera.com.invalid> wrote: > Hi Chris, > > Would you mind testing the following patch on your test clusters? > I'm not entirely sure, but the issue might be related. > > https://issues.apache.org/jira/browse/ZOOKEEPER-2930 > > Regards, > Andor > > > > On Wed, Aug 8, 2018 at 6:51 PM, Camille Fournier <cami...@apache.org> > wrote: > > > If you have the time and inclination, next time you see this problem in > > your test clusters get stack traces and any other diagnostics possible > > before restarting. I'm not an expert at network debugging but if you have > > someone who is you might want them to take a look at the connections and > > settings of any switches/firewalls/etc involved, see if there's any > unusual > > configurations or evidence of other long-lived connections failing (even > if > > their services handle the failures more gracefully). Send us the stack > > traces also it would be interesting to take a look. > > > > C > > > > > > On Wed, Aug 8, 2018, 11:09 AM Chris <c.turks...@gmail.com> wrote: > > > > > Running 3.5.5 > > > > > > I managed to recreate it on acc and test cluster today, failing on > > > shutdown > > > of leader. Both had been running for over a week. After restarting all > > > zookeepers it runs fine no matter how many leader shutdowns i throw at > > it. > > > > > > On 8 August 2018 5:05:34 pm Andor Molnar <an...@cloudera.com.INVALID> > > > wrote: > > > > > > > Some kind of a network split? > > > > > > > > It looks like 1-2 and 3-4 were able to communicate each other, but > > > > connection timed out between these 2 splits. When 5 came back online > it > > > > started with supporters of (1,2) and later 3 and 4 also joined. > > > > > > > > There was no such issue the day after. > > > > > > > > Which version of ZooKeeper is this? 3.5.something? > > > > > > > > Regards, > > > > Andor > > > > > > > > > > > > > > > > On Wed, Aug 8, 2018 at 4:52 PM, Chris <c.turks...@gmail.com> wrote: > > > > > > > >> Actually i have similar issues on my test and acceptance clusters > > where > > > >> leader election fails if the cluster has been running for a couple > of > > > days. > > > >> If you stop/start the Zookeepers once they will work fine on further > > > >> disruptions that day. Not sure yet what the treshold is. > > > >> > > > >> > > > >> On 8 August 2018 4:32:56 pm Camille Fournier <cami...@apache.org> > > > wrote: > > > >> > > > >> Hard to say. It looks like about 15 minutes after your first > incident > > > where > > > >>> 5 goes down and then comes back up, servers 1 and 2 get socket > errors > > > to > > > >>> their connections with 3, 4, and 6. It's possible if you had waited > > > those > > > >>> 15 minutes, once those errors cleared the quorum would've formed > with > > > the > > > >>> other servers. But as for why there were those errors in the first > > > place > > > >>> it's not clear. Could be a network glitch, or an obscure bug in the > > > >>> connection logic. Has anyone else ever seen this? > > > >>> If you see it again, getting a stack trace of the servers when they > > > can't > > > >>> form quorum might be helpful. > > > >>> > > > >>> On Wed, Aug 8, 2018 at 11:52 AM Cee Tee <c.turks...@gmail.com> > > wrote: > > > >>> > > > >>> I have a cluster of 5 participants (id 1-5) and 1 observer (id 6). > > > >>>> 1,2,5 are in datacenter A. 3,4,6 are in datacenter B. > > > >>>> Yesterday one of the participants (id5, by chance was the leader) > > was > > > >>>> rebooted. Although all other servers were online and not suffering > > > from > > > >>>> networking issues the leader election failed and the cluster > > remained > > > >>>> "looking" until the old leader came back online after which it was > > > >>>> promptly > > > >>>> elected as leader again. > > > >>>> > > > >>>> Today we tried the same exercise on the exact same servers, 5 was > > > still > > > >>>> leader and was rebooted, and leader election worked fine with 4 as > > new > > > >>>> leader. > > > >>>> > > > >>>> I have included the logs. From the logs i see that yesterday 1,2 > > > never > > > >>>> received new leader proposals from 3,4 and vice versa. > > > >>>> Today all proposals came through. This is not the first time we've > > > seen > > > >>>> this type of behavior, where some zookeepers can't seem to find > each > > > >>>> other > > > >>>> after the leader goes down. > > > >>>> All servers use dynamic configuration and have the same config > node. > > > >>>> > > > >>>> How could this be explained? These servers also host a replicated > > > >>>> database > > > >>>> cluster and have no history of db replication issues. > > > >>>> > > > >>>> Thanks, > > > >>>> Chris > > > >>>> > > > >>>> > > > >>>> > > > >>>> > > > >> > > > >> > > > >> > > > > > > > > > > > > > > >
