No master to send allocate dangled request – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-7.17

Briefly, this error occurs when Elasticsearch cannot find a master node to allocate a dangled index. A dangled index is an index that exists on a node but is not part of the cluster state. This can happen due to network issues or if the master node is down. To resolve this issue, you can try restarting the master node, ensuring network connectivity between nodes, or manually adding the dangled index to the cluster state. If the problem persists, consider checking your cluster’s health and configuration.

This guide will help you check for common problems that cause the log ” no master to send allocate dangled request ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: master, request, dangled.

Log Context

Log “no master to send allocate dangled request” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 public void allocateDangled(Collection indices; ActionListener listener) {
 ClusterState clusterState = clusterService.state();
 DiscoveryNode masterNode = clusterState.nodes().getMasterNode();
 if (masterNode == null) {
 listener.onFailure(new MasterNotDiscoveredException("no master to send allocate dangled request"));
 AllocateDangledRequest request = new AllocateDangledRequest(
 indices.toArray(new IndexMetadata[indices.size()])