I recently upgraded a few clusters from version 5.2.2 -> 5.5.2. Since the upgrade I'm seeing a lot of InternalReplicaShardAllocator warnings in the Elasticsearch logs that seem to indicate a failing node. I'm not seeing nodes drop out of the cluster though or the cluster status go yellow/red. This seems to be happening in bursts every ~7-8 hours. Has anyone else run into this?
An example of the warning messages from the logs: