The X-Pack monitoring components enable you to easily monitor the Elastic Stack from Kibana. You can view health and performance data for Elasticsearch, Logstash, and Kibana in real time, as well as analyze past performance.
When you install X-Pack, a monitoring agent runs on each Elasticsearch, Kibana, and Logstash instance to collect and index metrics.
By default, metrics are indexed within the cluster you are monitoring. Setting up a dedicated monitoring cluster ensures you can access historical monitoring data even if the cluster you’re monitoring goes down. It also enables you to monitor multiple clusters from a central location.
When you use a dedicated monitoring cluster, the metrics collected by the Logstash and Kibana monitoring agents are shipped to the Elasticsearch cluster you’re monitoring, which then forwards all of the metrics to the monitoring cluster.