Unfortunately there are more than one Plugin that was named check_elasticsearch.
The one that has a corresponding CheckCommand in the ITL only works for Elasticsearch version < 5.
What works is the following:
But there is still no way to add CheckCommands with conflicting plugin names to the ITL. As far as I know there’s a way coming up.
You might want to use check_logfiles or a dedicated Elastic Stack to monitor the logs of Elasticsearch. Reading the logs with a beat instance that sends in the same cluster might lead to a loop and lots of pain.