Error Message "maximum shards open" Is Displayed When Users Try to Create an Index

Symptom

When users try to create an index, an error message is displayed: "this action would add [2] total shards, but this cluster currently has [1000]/[1000] maximum shards open".

Possible Cause

By default, each node can support a maximum of 1000 shards. An error is reported when this limit is exceeded.

Solution

• Solution 1: Disable or delete unused indexes to reduce the number of shards.
• Solution 2: Change the limit on the maximum number of shards per node. For details, see max_shards_per_node.

  PUT _cluster/settings
  {
    "persistent": {
      "cluster": {
        "max_shards_per_node": 2000
      }
    }
  }

Changing the limit on the maximum number of shards per node is just a temporary fix. To solve this issue in the long term, aim for 20 shards or fewer per GB of JVM heap memory (each node should have a heap memory size that is 50% of the node's available memory, up to 31 GB). For more information, see shard count recommendation.