A quick one:
I have a number of Elasticsearch clusters that we monitor.
We set some configuration settings in the elasticsearch.yml file, e.g. minimum_master_nodes and thread-pools.
Is there a way to read the current value of these settings via the REST interface? _cluster/settings only contains what was set via REST (see https://www.elastic.co/guide/en/elasticsearch/reference/2.3/cluster-update-settings.html), but not things that were read via the config-files so I did not find a way to check which value a cluster currently actually uses...