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

Allows to update cluster wide specific settings. Settings updated can
either be persistent (applied cross restarts) or transient (will not
survive a full cluster restart). Here is an example:

[source,js]
--------------------------------------------------
curl -XPUT localhost:9200/_cluster/settings -d '{
    "persistent" : {
        "discovery.zen.minimum_master_nodes" : 2
    } 
}' 
--------------------------------------------------

Or:

[source,js]
--------------------------------------------------
curl -XPUT localhost:9200/_cluster/settings -d '{
    "transient" : {
        "discovery.zen.minimum_master_nodes" : 2
    } 
}' 
--------------------------------------------------

The cluster responds with the settings updated. So the response for the
last example will be:

[source,js]
--------------------------------------------------
{
    "persistent" : {},
    "transient" : {
        "discovery.zen.minimum_master_nodes" : "2"
    } 
}' 
--------------------------------------------------

Cluster wide settings can be returned using:

[source,js]
--------------------------------------------------
curl -XGET localhost:9200/_cluster/settings
--------------------------------------------------

There is a specific list of settings that can be updated, those include:

[float]
[[cluster-settings]]
=== Cluster settings

[float]
==== Routing allocation

[float]
===== Awareness

`cluster.routing.allocation.awareness.attributes`::
     See <<modules-cluster>>.

`cluster.routing.allocation.awareness.force.*`::
     See <<modules-cluster>>.

[float]
===== Balanced Shards
All these values are relative to one another.  The first three are used to
compose a three separate weighting functions into one.  The cluster is balanced
when no allowed action can bring the weights of each node closer together by
more then the fourth setting.  Actions might not be allowed, for instance,
due to forced awareness or allocation filtering.

`cluster.routing.allocation.balance.shard`::
     Defines the weight factor for shards allocated on a node
     (float). Defaults to `0.45f`.  Raising this raises the tendency to
     equalize the number of shards across all nodes in the cluster.

`cluster.routing.allocation.balance.index`::
     Defines a factor to the number of shards per index allocated
      on a specific node (float). Defaults to `0.55f`.  Raising this raises the
      tendency to equalize the number of shards per index across all nodes in
      the cluster.

`cluster.routing.allocation.balance.threshold`::
     Minimal optimization value of operations that should be performed (non
      negative float). Defaults to `1.0f`.  Raising this will cause the cluster
      to be less aggressive about optimizing the shard balance.

[float]
===== Concurrent Rebalance

`cluster.routing.allocation.cluster_concurrent_rebalance`::
       Allow to control how many concurrent rebalancing of shards are 
       allowed cluster wide, and default it to `2` (integer). `-1` for 
       unlimited. See also <<modules-cluster>>.

[float]
===== Enable allocation

`cluster.routing.allocation.enable`::
     See <<modules-cluster>>.

[float]
===== Throttling allocation

`cluster.routing.allocation.node_initial_primaries_recoveries`::
     See <<modules-cluster>>.

`cluster.routing.allocation.node_concurrent_recoveries`::
     See <<modules-cluster>>.

[float]
===== Filter allocation

`cluster.routing.allocation.include.*`::
     See <<modules-cluster>>.

`cluster.routing.allocation.exclude.*`::
     See <<modules-cluster>>.

`cluster.routing.allocation.require.*` 
     See <<modules-cluster>>.

[float]
==== Metadata

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

[float]
==== Discovery

`discovery.zen.minimum_master_nodes`::
     See <<modules-discovery-zen>>

`discovery.zen.publish_timeout`::
     See <<modules-discovery-zen>>

[float]
==== Threadpools

`threadpool.*`::
     See <<modules-threadpool>>

[float]
[[cluster-index-settings]]
=== Index settings

[float]
==== Index filter cache

`indices.cache.filter.size`::
     See <<index-modules-cache>>

`indices.cache.filter.expire` (time)::
     See <<index-modules-cache>>

[float]
==== TTL interval

`indices.ttl.interval` (time):: 
    See <<mapping-ttl-field>>

[float]
==== Recovery

`indices.recovery.concurrent_streams`::
     See <<modules-indices>>

`indices.recovery.file_chunk_size`::
     See <<modules-indices>>

`indices.recovery.translog_ops`::
     See <<modules-indices>>

`indices.recovery.translog_size`::
     See <<modules-indices>>

`indices.recovery.compress`::
     See <<modules-indices>>

`indices.recovery.max_bytes_per_sec`::
     See <<modules-indices>>

[float]
[[logger]]
=== Logger

Logger values can also be updated by setting `logger.` prefix. More
settings will be allowed to be updated.

[float]
=== Field data circuit breaker

`indices.breaker.fielddata.limit`::
     See <<index-modules-fielddata>>

`indices.breaker.fielddata.overhead`::
     See <<index-modules-fielddata>>