Re: Port 3888 closed on Leader
Thanks Everyone. Yes, even i was wondering how can a node can be leader without port 3888 being open, we just did a restart and everything became fine. Port 3888 must be in LISTEN mode at all Zk Nodes , while 2888 only opens at leader and other nodes connect to it. Thanks Harish On Thu, Aug 23, 2018 at 6:47 AM Shawn Heisey wrote: > On 8/15/2018 7:46 AM, harish lohar wrote: > > In a deployment of 3 Node Zk Cluster we have seen that sometime port 3888 > > is absent after the cluster is formed , this causes Follower node to not > > able to connect to leader if they restart. > > > > Don't leader itself should come out of clustering if this happens ?? > > I'm not well-versed in how ZK works internally, and don't have access > any more to systems I can check, but I seem to remember when looking at > a live ensemble that not every ZK instance will bind to all three ports > (2181, 2888, and 3888 if using the example configs). Surprised me when > I noticed it, but I didn't worry about it too much since ZK seemed to be > working correctly. > > Thanks, > Shawn > >
Re: Port 3888 closed on Leader
On 8/15/2018 7:46 AM, harish lohar wrote: In a deployment of 3 Node Zk Cluster we have seen that sometime port 3888 is absent after the cluster is formed , this causes Follower node to not able to connect to leader if they restart. Don't leader itself should come out of clustering if this happens ?? I'm not well-versed in how ZK works internally, and don't have access any more to systems I can check, but I seem to remember when looking at a live ensemble that not every ZK instance will bind to all three ports (2181, 2888, and 3888 if using the example configs). Surprised me when I noticed it, but I didn't worry about it too much since ZK seemed to be working correctly. Thanks, Shawn
Re: Port 3888 closed on Leader
Hi, I don't fully understand the events here, but as I see: - Leader election port should not just disappear, maybe some config issue? - If a follower is unable to join back in the quorum, but there is still n/2 + 1 nodes functioning (in case of 3 nodes - 2 functioning nodes), the quorum will work without a problem, and leader will not come out of the cluster. Regards, Norbert On Wed, Aug 15, 2018 at 3:46 PM harish lohar wrote: > Hi, > > In a deployment of 3 Node Zk Cluster we have seen that sometime port 3888 > is absent after the cluster is formed , this causes Follower node to not > able to connect to leader if they restart. > > Don't leader itself should come out of clustering if this happens ?? > > Thanks > Harish >
