Miscellaneous cluster settings

Metadata

An entire cluster may be set to read-only with the following dynamic setting:

cluster.blocks.read_only
Make the whole cluster read only (indices do not accept write operations), metadata is not allowed to be modified (create or delete indices).

Don’t rely on this setting to prevent changes to your cluster. Any user with access to the cluster-update-settings API can make the cluster read-write again.

Logger

The settings which control logging can be updated dynamically with the logger. prefix. For instance, to increase the logging level of the indices.recovery module to DEBUG, issue this request:

PUT /_cluster/settings
{
  "transient": {
    "logger.indices.recovery": "DEBUG"
  }
}