elasticsearch/docs/reference/cluster/update-settings.asciidoc

[[cluster-update-settings]]
=== Cluster Update Settings

Updates cluster-wide settings. 


[[cluster-update-settings-api-request]]
==== {api-request-title}

`PUT /_cluster/settings`


[[cluster-update-settings-api-desc]]
==== {api-description-title}

With specifications in the request body, this API call can update cluster 
settings. Updates to settings can be persistent, meaning they apply across 
restarts, or transient, where they don't survive a full cluster restart.

You can reset persistent or transient settings by assigning a `null` value. If a 
transient setting is reset, the first one of these values that is defined is 
applied:

* the persistent setting
* the setting in the configuration file
* the default value. 

The order of precedence for cluster settings is:

1. transient cluster settings 
2. persistent cluster settings
3. settings in the `elasticsearch.yml` configuration file.

It's best to set all cluster-wide settings with the `settings` API and use the
`elasticsearch.yml` file only for local configurations. This way you can be sure that
the setting is the same on all nodes. If, on the other hand, you define different
settings on different nodes by accident using the configuration file, it is very
difficult to notice these discrepancies.

You can find the list of settings that you can dynamically update in 
<<modules,Modules>>.


[[cluster-update-settings-api-query-params]]
==== {api-query-parms-title}

include::{docdir}/rest-api/common-parms.asciidoc[tag=flat-settings]

`include_defaults`::
    (Optional, boolean) If `true`, returns all default cluster settings. 
    Defaults to `false`.

include::{docdir}/rest-api/common-parms.asciidoc[tag=timeoutparms]


[[cluster-update-settings-api-example]]
==== {api-examples-title}

An example of a persistent update:

[source,js]
--------------------------------------------------
PUT /_cluster/settings
{
    "persistent" : {
        "indices.recovery.max_bytes_per_sec" : "50mb"
    }
}
--------------------------------------------------
// CONSOLE


An example of a transient update:

[source,js]
--------------------------------------------------
PUT /_cluster/settings?flat_settings=true
{
    "transient" : {
        "indices.recovery.max_bytes_per_sec" : "20mb"
    }
}
--------------------------------------------------
// CONSOLE


The response to an update returns the changed setting, as in this response to 
the transient example:

[source,js]
--------------------------------------------------
{
    ...
    "persistent" : { },
    "transient" : {
        "indices.recovery.max_bytes_per_sec" : "20mb"
    }
}
--------------------------------------------------
// TESTRESPONSE[s/\.\.\./"acknowledged": true,/]


This example resets a setting:

[source,js]
--------------------------------------------------
PUT /_cluster/settings
{
    "transient" : {
        "indices.recovery.max_bytes_per_sec" : null
    }
}
--------------------------------------------------
// CONSOLE


The response does not include settings that have been reset:

[source,js]
--------------------------------------------------
{
    ...
    "persistent" : {},
    "transient" : {}
}
--------------------------------------------------
// TESTRESPONSE[s/\.\.\./"acknowledged": true,/]


You can also reset settings using wildcards. For example, to reset
all dynamic `indices.recovery` settings:

[source,js]
--------------------------------------------------
PUT /_cluster/settings
{
    "transient" : {
        "indices.recovery.*" : null
    }
}
--------------------------------------------------
// CONSOLE