Briefly, this error occurs when a node tries to join an Elasticsearch cluster but fails the validation process. This could be due to version mismatch, different cluster names, or network issues. To resolve this, ensure all nodes have the same Elasticsearch version and cluster name. Check your network settings and firewall rules to ensure nodes can communicate. Also, verify the node’s configuration files for any discrepancies.
To understand why Elasticsearch failed to validate incoming join requests from certain nodes, and what impact this will have on your system, you should run the Elasticsearch Error Check-Up. It’ll give you a better grasp of what is happening in your system and assist you in resolving issues.
This guide will help you check for common problems that cause the log “Failed to validate incoming join request from node” to appear. It’s important to understand the issues related to it, so to get started, read the general overview on common issues and tips related to the Elasticsearch concepts: discovery, join, node and request.
Overview
To put it simply, a node is a single server that is part of a cluster. Each node is assigned one or more roles, which describe the node’s responsibility and operations. Data nodes store the data, and participate in the cluster’s indexing and search capabilities, while master nodes are responsible for managing the cluster’s activities and storing the cluster state, including the metadata.
While it is possible to run several node instances of Elasticsearch on the same hardware, it’s considered a best practice to limit a server to a single running instance of Elasticsearch.
Nodes connect to each other and form a cluster by using a discovery method.
Roles
Master node
Master nodes are in charge of cluster-wide settings and changes – deleting or creating indices and fields, adding or removing nodes and allocating shards to nodes. Each cluster has a single master node that is elected from the master eligible nodes using a distributed consensus algorithm and is reelected if the current master node fails.
Coordinating (client) node
There is some confusion in the use of coordinating node terminology. Client nodes were removed from Elasticsearch after version 2.4 and became coordinating nodes.
Coordinating nodes are nodes that do not hold any configured role. They don’t hold data and are not part of the master eligible group nor execute ingest pipelines. Coordinating nodes serve incoming search requests and act as the query coordinator running query and fetch phases, sending requests to every node that holds a shard being queried. The coordinating node also distributes bulk indexing operations and route queries to shards based on the node’s responsiveness.
Log Context
Log “failed to validate incoming join request from node [{}]” classname is Coordinator.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
discoveryNode;
JoinHelper.JOIN_VALIDATE_ACTION_NAME;
new ValidateJoinRequest(clusterState);
TransportRequestOptions.of(null; TransportRequestOptions.Type.STATE);
new ActionListenerResponseHandler(listener.delegateResponse((l; e) -> {
logger.warn(() -> new ParameterizedMessage("failed to validate incoming join request from node [{}]"; discoveryNode); e);
listener.onFailure(
new IllegalStateException(
String.format(
Locale.ROOT;
"failure when sending a join validation request from [%s] to [%s]";
