Node discovery

When you start your Elasticsearch node, one of the first things to occur is that the node starts looking for a master node that has the same cluster name and is visible. If a master is found, the node joins a cluster that is already formed. If no master is found, the node itself is selected as a master (of course, if the configuration allows such a behavior). The process of forming a cluster and finding nodes is called discovery. The module that is responsible for discovery has two main purposes—to elect a master and to discover new nodes within a cluster. In this section, we will discuss how we can configure and tune the discovery module.

Discovery types

By default, without installing additional plugins, Elasticsearch allows us to use the zen discovery, which provides us with multicast and unicast discovery. In computer networking terminology, multicast (http://en.wikipedia.org/wiki/Multicast) is the delivery of a message to a group of computers in a single transmission. On...