Monitoring a Solr Cluster

A couple of days ago I got asked, how do we monitor our cluster? Well, there are professional ways and other for the budget conscious deployment. Here are a few options that came to my mind:

• You have the ping request handler which can be used to determine if a node is up and running – this is useful if you want to configure the load balancer to determine which nodes are responding
• Additionally I’ve seen environments where a monitoring service uses several predefined queries that are issued at a predefined interval and will notify if no response is received. Something like http://www.site24x7.com/ but behind the firewall. I do not know which/if monitoring services you might have.
• And there are more specialized tools, for example Sematext although some of them are more Linux friendly, so it is necessary to look for Windows counterparts if you don’t have Linux.
• Also you can use the clusterstate.json (this would be the one from prod https:///solr/zookeeper?detail=true&path=/clusterstate.json) from Zookeepr which will tell you the state of the nodes. You just need to do a bit of parsing which can be done pretty easily with a bit of Json.Net which is easy to learn.
• And regarding monitoring your cluster’s use in terms of queries done, you can definitively use the Solr logs and analyze queries.

Just a few thoughts I wanted to share.