Class JoinValidationService

java.lang.Object
org.elasticsearch.cluster.coordination.JoinValidationService

public class JoinValidationService extends Object
Coordinates the join validation process.

When a node requests to join an existing cluster, the master first sends it a copy of a recent cluster state to ensure that the new node can make sense of it (e.g. it has all the plugins it needs to even deserialize the state). Cluster states can be expensive to serialize: they are large, so we compress them, but the compression takes extra CPU. Also there may be many nodes all joining at once (e.g. after a full cluster restart or the healing of a large network partition). This component caches the serialized and compressed state that was sent to one joining node and reuses it to validate other join requests that arrive within the cache timeout, avoiding the need to allocate memory for each request and repeat all that serialization and compression work each time.