Apache Curator: Invalid config event received

The exception looks like this:

o.a.c.framework.imps.EnsembleTracker Invalid config event received: {server.1=host1:2888:3888:participant, version=0, server.3=host3:2888:3888:participant, server.2=host2:2888:3888:participant}

We know, that in zookeeper.properties (or zoo.cfg) there is a cluster configuration of the following type:

clientPort=1236
server.1 = 125.24.43.32:1234:1235
server.2 = 125.24.43.33:1234:1235
...

From a certain version of ZooKeeper, it became like this https://zookeeper.apache.org/doc/r3.5.3-beta/zookeeperReconfig.html#ch_reconfig_format:

server.1 = 125.24.43.32:1234:1235;1236
server.2 = 125.24.43.33:1234:1235;1236
...

Apache Curator switched to a new format, discontinuing support for the old one. However, ZooKeeper kept it: on the same page in the Backward Compatibility section, there is information states that the old format can be used: https://zookeeper.apache.org/doc/r3.5.3-beta/zookeeperReconfig.html#sc_reconfig_backward.

In support of the fact that the ZK should support the old way:

1. The inability to specify the SSL port in the line 125.24.43.32:1234:1235;1236;
2. The fact that the ZK works correctly in cluster mode with the “old” configuration format.

Therefore, this is the Apache Curator bug. Curator should recognize the old way of specifying the cluster configuration. Jira bug ticket: https://issues.apache.org/jira/browse/CURATOR-526.

Solution: update the Curator version to 5.1.1, or add a client port in the ZK dynamic (cluster) configuration.

If you still have any questions, feel free to ask me in the comments under this article or write me at promark33@gmail.com.

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