Our Marvel monitoring tab in the Kibana UI disappeared today. Our setup is as follows
/etc/kibana/kibana.yml
xpack.security.enabled: false
xpack.monitoring.enabled: true
And to collect data from particular indices, we configured the xpack.monitoring.collection.indices setting as described here.
/etc/elasticsearch/elasticsearch.yml
xpack.monitoring.collection.indices: +test-*
I verified these configs are being used and we restarted kibana and elasticsearch.