Book Image

Mastering Elasticsearch - Second Edition

Book Image

Mastering Elasticsearch - Second Edition

Overview of this book

Table of Contents (19 chapters)
Mastering Elasticsearch Second Edition
Credits
About the Author
Acknowledgments
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Discovery and recovery modules


When starting your Elasticsearch node, one of the first things that Elasticsearch does is look for a master node that has the same cluster name and is visible in the network. If a master node is found, the starting node gets joined into an already formed cluster. If no master is found, then the node itself is selected as a master (of course, if the configuration allows such behavior). The process of forming a cluster and finding nodes is called discovery. The module responsible for discovery has two main purposes—electing a master and discovering new nodes within a cluster.

After the cluster is formed, a process called recovery is started. During the recovery process, Elasticsearch reads the metadata and the indices from the gateway, and prepares the shards that are stored there to be used. After the recovery of the primary shards is done, Elasticsearch should be ready for work and should continue with the recovery of all the replicas (if they are present...