Shard rebalancing restricted

Shard rebalancing is turned off or restricted, so the cluster cannot move shards off overloaded disks or onto newly added nodes within your allocation rules. Disk and CPU skew can persist until hot nodes saturate while others stay underused.

Note

For a complete list of insights, refer to AutoOps insights.

Insight details

Field	Value
Component	Elasticsearch
Severity	Medium
Scope	Cluster
Domains	performance, configuration, shard-allocation

Example: What you might see in AutoOps

The following is an example of what you might see when this insight is triggered. Real insights use live data and links from your deployment or cluster.

Shard rebalancing is not fully enabled

What was detected

cluster.routing.rebalance.enable is not set to all. Shard rebalancing is turned off or limited.

Recommendations

Note

AutoOps shows different recommendations depending on how their conditions match your deployment or cluster.

Condition: Always shown for this insight.

Reset cluster.routing.rebalance.enable so primary and replica shards can rebalance across nodes.

						PUT _cluster/settings
					{
  "transient": {
    "cluster.routing.rebalance.enable": null
  },
  "persistent": {
    "cluster.routing.rebalance.enable": null
  }
}
		
	

Note

Requires the manage cluster privilege. Requires Elasticsearch 8.0.0 or later. This action changes cluster or index configuration.

Background and impact

Shard rebalancing is how the master moves shards to improve balance across data nodes, for example from high disk utilization to lower utilization, or onto a newly added node.

Operators sometimes turn off rebalancing during maintenance. While it stays off, the cluster cannot correct skew from growth, node addition, or uneven indexing. Overloaded nodes keep more load than they should.

Re-enable rebalancing (all) when maintenance is done so the master can optimize placement within your allocation filters and disk watermarks.