In this chapter, we covered most of the topics related to the administration of Elasticsearch. We started with describing different types of nodes and how to configure them and then looked into Elasticsearch discovery and recovery modules in detail. Next, we covered the cat API of Elasticsearch, which is very useful in finding out node/cluster/index stats in a very readable format. Finally, we discussed snapshot and restore APIs, which allow you to perform an incremental backup of various repositories, such as shared filesystems or clouds, and to restore the snapshots back into the cluster.
In the next chapter, we will cover one of the most exciting features introduced in Elasticsearch: the ingest node, which allows us to preprocess the data into the Elasticsearch cluster itself before indexing. We will also look into how a federated search works with different clusters using tribe nodes.