Join target is a follower – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 7-8.9

Briefly, this error occurs when you attempt to perform a join operation on a follower index in Elasticsearch. Follower indices are used in cross-cluster replication and are read-only, hence they cannot be used for join operations. To resolve this issue, you can either perform the join operation on the leader index instead, or pause the replication, make the follower index into a regular index, perform the join operation, and then resume the replication. Alternatively, you can create a new regular index, copy the data from the follower index to the new index, and then perform the join operation.

This guide will help you check for common problems that cause the log ” join target is a follower ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: join, cluster.

Log Context

Log “join target is a follower” class name is JoinHelper.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 }  static class FollowerJoinAccumulator implements JoinAccumulator {
 @Override
 public void handleJoinRequest(DiscoveryNode sender; TransportVersion transportVersion; ActionListener joinListener) {
 joinListener.onFailure(new CoordinationStateRejectedException("join target is a follower"));
 }  @Override
 public String toString() {
 return "FollowerJoinAccumulator";

 

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