Issue

• Fluentd dropping logs and getting the 401 error message:

2018-07-24 07:45:44 -0400 [warn]: temporarily failed to flush the buffer. next_retry=2018-07-24 07:45:45 -0400 error_class="Elasticsearch::Transport::Transport::Errors::Unauthorized" error="[401] " plugin_id="object:14f34e4"

• Message in Elasticsearch with corresponding timestamp:

[2018-07-24 07:45:36,488][WARN ][rest.suppressed          ] path: /_bulk, params: {}
java.util.ConcurrentModificationException

• Also seeing in Elasticsearch could not authenticate user messages:

[2018-07-24 16:28:35,715][INFO ][io.fabric8.elasticsearch.plugin.acl.DynamicACLFilter] Could not authenticate user
[2018-07-24 16:28:47,723][INFO ][io.fabric8.elasticsearch.plugin.acl.DynamicACLFilter] Could not authenticate user
[2018-07-24 16:28:59,711][INFO ][io.fabric8.elasticsearch.plugin.acl.DynamicACLFilter] Could not authenticate user
[2018-07-24 16:29:11,713][INFO ][io.fabric8.elasticsearch.plugin.acl.DynamicACLFilter] Could not authenticate user