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 <[email protected]> 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 <[email protected]> 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 <[email protected]> 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 >>> >>> >>> >>> > > >
