Thomas- Encouraging news. Appreciate the response.
I've tried both non-incremental and incremental reconfigs with the same result. With 3 zk participants (quorum 2) we first add 3 observers. Non-incrementally we then remove a participant then add an observer as participant. Repeat twice, last time the current leading participant is the one removed. At this point the 3 mesos-masters all seem fine. My bespoke framework is fine too, it sees CONNECT, RECONNECT, and RECONFIG events and gets the updated list of zk participants just fine. But when we terminate the original zk servers that are now running as non-voting followers, the mesos-masters all seem to keep trying to reconnect to the now-dead former zk participants. Eventually heartbeats fail and the whole cluster shuts down. The masters log messages like: 2022-03-08 13:26:45,964:30032(0x7f25a3048700):ZOO_INFO@zookeeper_init@827: > Initiating client connection, > host=localhost:2181,localhost:2182,localhost:2183 sessionTimeout=10000 > watcher=0x7f25ba3af67e sessionId=0 sessionPasswd=<null> > context=0x7f255c000bf8 flags=0 > 2022-03-08 > 13:26:45,964:30032(0x7f25565ea700):ZOO_ERROR@handle_socket_error_msg@1758: > Socket [::1:2183] zk retcode=-4, errno=111(Connection refused): server > refused to accept the client > 2022-03-08 > 13:26:45,964:30032(0x7f25565ea700):ZOO_ERROR@handle_socket_error_msg@1758: > Socket [127.0.0.1:2182] zk retcode=-4, errno=111(Connection refused): > server refused to accept the client > 2022-03-08 > 13:26:45,964:30032(0x7f25565ea700):ZOO_ERROR@handle_socket_error_msg@1758: > Socket [::1:2181] zk retcode=-4, errno=111(Connection refused): server > refused to accept the client > 2022-03-08 > 13:26:45,965:30032(0x7f25565ea700):ZOO_ERROR@handle_socket_error_msg@1758: > Socket [127.0.0.1:2181] zk retcode=-4, errno=111(Connection refused): > server refused to accept the client > 2022-03-08 > 13:26:45,965:30032(0x7f25565ea700):ZOO_ERROR@handle_socket_error_msg@1758: > Socket [127.0.0.1:2183] zk retcode=-4, errno=111(Connection refused): > server refused to accept the client > 2022-03-08 > 13:26:45,965:30032(0x7f2557ded700):ZOO_ERROR@handle_socket_error_msg@1758: > Socket [127.0.0.1:2182] zk retcode=-4, errno=111(Connection refused): > server refused to accept the client > 2022-03-08 > 13:26:45,965:30032(0x7f2557ded700):ZOO_ERROR@handle_socket_error_msg@1758: > Socket [::1:2182] zk retcode=-4, errno=111(Connection refused): server > refused to accept the client > 2022-03-08 > 13:26:45,965:30032(0x7f2557ded700):ZOO_ERROR@handle_socket_error_msg@1758: > Socket [127.0.0.1:2181] zk retcode=-4, errno=111(Connection refused): > server refused to accept the client > 2022-03-08 > 13:26:45,965:30032(0x7f2557ded700):ZOO_ERROR@handle_socket_error_msg@1758: > Socket [::1:2181] zk retcode=-4, errno=111(Connection refused): server > refused to accept the client > 2022-03-08 > 13:26:45,965:30032(0x7f2557ded700):ZOO_ERROR@handle_socket_error_msg@1758: > Socket [::1:2183] zk retcode=-4, errno=111(Connection refused): server > refused to accept the client > 2022-03-08 > 13:26:45,965:30032(0x7f2557ded700):ZOO_ERROR@handle_socket_error_msg@1758: > Socket [127.0.0.1:2183] zk retcode=-4, errno=111(Connection refused): > server refused to accept the client > Where ports 2181, 2182, 2183 are the old participants, the new participants are on ports 2184, 2185, 2186 (single host test environment). Perhaps a mesos-master needs to be terminated and then restarted with an updated zk:// list as each zk participant gets reconfig'ed? -Dan On Thu, Mar 10, 2022 at 5:15 AM Thomas Langé <[email protected]> wrote: > Hi, > > We don't run mesos 1.11 but we use Zookeeper with dynamic reconfiguration > capability without any issue for Mesos 1.9. The only thing that should be > handled carefully is the addition/removal of Zookeeper members when using > dynamic reconf feature. > > What do you mean by "mesos-master can handle a dynamic reconfiguration of > the zk ensemble" ? To my understanding, Mesos will only connect to ZK to > elect a leader through ZK primitives; I don't think there is a correlation > with how ZK members are set in the cluster. > > How do you remove/add members to the ZK member list? The issue you > encounter might come from inconsistencies in ZK cluster. > > Regards, > > Thomas > ------------------------------ > *From:* Charles-François Natali <[email protected]> > *Sent:* Wednesday, 9 March 2022 23:44 > *To:* user <[email protected]> > *Subject:* [BULK]Re: Mesos and Zookeeper Dynamic Reconfiguration? > > Hi Dan, > > I don't think anyone has been looking at this, and i doubt we will, since > we are quite low on resources. > > > Cheers, > > > > > On Tue, Mar 8, 2022, 19:01 Dan Leary <[email protected]> wrote: > > Been doing some testing with mesos 1.11.0 and zookeeper's "dynamic > reconfiguration" capability. > https://zookeeper.apache.org/doc/r3.6.3/zookeeperReconfig.html > <https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fzookeeper.apache.org%2Fdoc%2Fr3.6.3%2FzookeeperReconfig.html&data=04%7C01%7Ct.lange%40criteo.com%7C070fc8a5cd6341e9a91008da021e7876%7C2a35d8fd574d48e3927c8c398e225a01%7C1%7C0%7C637824627127329223%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=AjPUBCzFNsu0twnGptmACWDH8%2FTUktvVYKarGBRtGJI%3D&reserved=0> > > Seems prima facie like mesos-master can handle a dynamic reconfig of the > zk ensemble up to the point > where a new set of participants has been added to the ensemble and the old > participants > have been demoted to non-voting followers. But when the non-voting > follower processes are > terminated the master logs seem to indicate that the masters keep trying > and failing to reconnect > to the old zk leader, even though they've apparently received updates with > the new ensemble participants. > > Anybody have any insight into this? > Any plans to support zk dynamic reconfiguration in the future? > Seems like it could make for easier O/S maintenance of one's master/zk > cluster hosts. > > -Dan > >
