[[cluster-nodes-stats]]
== Nodes Stats

[float]
=== Nodes statistics

The cluster nodes stats API allows to retrieve one or more (or all) of
the cluster nodes statistics.

[source,js]
--------------------------------------------------
GET /_nodes/stats
GET /_nodes/nodeId1,nodeId2/stats
--------------------------------------------------
// CONSOLE

The first command retrieves stats of all the nodes in the cluster. The
second command selectively retrieves nodes stats of only `nodeId1` and
`nodeId2`. All the nodes selective options are explained
<<cluster-nodes,here>>.

By default, all stats are returned. You can limit this by combining any
of `indices`, `os`, `process`, `jvm`, `transport`, `http`,
`fs`, `breaker` and `thread_pool`. For example:

[horizontal]
`indices`::
  Indices stats about size, document count, indexing and
  deletion times, search times, field cache size, merges and flushes

`fs`::
  File system information, data path, free disk space, read/write
  stats (see <<fs-info,FS information>>)

`http`::
  HTTP connection information

`jvm`::
  JVM stats, memory pool information, garbage collection, buffer
  pools, number of loaded/unloaded classes

`os`::
  Operating system stats, load average, mem, swap
  (see <<os-stats,OS statistics>>)

`process`::
  Process statistics, memory consumption, cpu usage, open
  file descriptors (see <<process-stats,Process statistics>>)

`thread_pool`::
  Statistics about each thread pool, including current
  size, queue and rejected tasks

`transport`::
  Transport statistics about sent and received bytes in
  cluster communication

`breaker`::
  Statistics about the field data circuit breaker

`discovery`::
  Statistics about the discovery

`ingest`::
  Statistics about ingest preprocessing

`adaptive_selection`::
  Statistics about <<search-adaptive-replica,adaptive replica selection>>. See
  <<adaptive-selection-stats,adaptive selection statistics>>.

[source,js]
--------------------------------------------------
# return just indices
GET /_nodes/stats/indices

# return just os and process
GET /_nodes/stats/os,process

# return just process for node with IP address 10.0.0.1
GET /_nodes/10.0.0.1/stats/process
--------------------------------------------------
// CONSOLE

All stats can be explicitly requested via `/_nodes/stats/_all` or `/_nodes/stats?metric=_all`.

[float]
[[fs-info]]
==== FS information

The `fs` flag can be set to retrieve
information that concern the file system:

`fs.timestamp`::
  Last time the file stores statistics have been refreshed

`fs.total.total_in_bytes`::
  Total size (in bytes) of all file stores

`fs.total.free_in_bytes`::
  Total number of unallocated bytes in all file stores

`fs.total.available_in_bytes`::
  Total number of bytes available to this Java virtual machine on all file stores.
  Depending on OS or process level restrictions, this might appear less than `fs.total.free_in_bytes`.
  This is the actual amount of free disk space the Elasticsearch node can utilise.

`fs.data`::
  List of all file stores

`fs.data.path`::
  Path to the file store

`fs.data.mount`::
  Mount point of the file store (ex: /dev/sda2)

`fs.data.type`::
  Type of the file store (ex: ext4)

`fs.data.total_in_bytes`::
  Total size (in bytes) of the file store

`fs.data.free_in_bytes`::
  Total number of unallocated bytes in the file store

`fs.data.available_in_bytes`::
  Total number of bytes available to this Java virtual machine on this file store

`fs.io_stats.devices` (Linux only)::
    Array of disk metrics for each device that is backing an
    Elasticsearch data path. These disk metrics are probed periodically
    and averages between the last probe and the current probe are
    computed.

`fs.io_stats.devices.device_name` (Linux only)::
    The Linux device name.

`fs.io_stats.devices.operations` (Linux only)::
    The total number of read and write operations for the device
    completed since starting Elasticsearch.

`fs.io_stats.devices.read_operations` (Linux only)::
    The total number of read operations for the device completed since
    starting Elasticsearch.

`fs.io_stats.devices.write_operations` (Linux only)::
    The total number of write operations for the device completed since
    starting Elasticsearch.

`fs.io_stats.devices.read_kilobytes` (Linux only)::
    The total number of kilobytes read for the device since starting
    Elasticsearch.

`fs.io_stats.devices.write_kilobytes` (Linux only)::
    The total number of kilobytes written for the device since
    starting Elasticsearch.

`fs.io_stats.operations` (Linux only)::
    The total number of read and write operations across all devices
    used by Elasticsearch completed since starting Elasticsearch.

`fs.io_stats.read_operations` (Linux only)::
    The total number of read operations for across all devices used by
    Elasticsearch completed since starting Elasticsearch.

`fs.io_stats.write_operations` (Linux only)::
    The total number of write operations across all devices used by
    Elasticsearch completed since starting Elasticsearch.

`fs.io_stats.read_kilobytes` (Linux only)::
    The total number of kilobytes read across all devices used by
    Elasticsearch since starting Elasticsearch.

`fs.io_stats.write_kilobytes` (Linux only)::
    The total number of kilobytes written across all devices used by
    Elasticsearch since starting Elasticsearch.

[float]
[[os-stats]]
==== Operating System statistics

The `os` flag can be set to retrieve statistics that concern
the operating system:

`os.timestamp`::
  Last time the operating system statistics have been refreshed

`os.cpu.percent`::
    Recent CPU usage for the whole system, or -1 if not supported

`os.cpu.load_average.1m`::
    One-minute load average on the system (field is not present if
    one-minute load average is not available)
`os.cpu.load_average.5m`::
    Five-minute load average on the system (field is not present if
    five-minute load average is not available)
`os.cpu.load_average.15m`::
    Fifteen-minute load average on the system (field is not present if
    fifteen-minute load average is not available)

`os.mem.total_in_bytes`::
  Total amount of physical memory in bytes

`os.mem.free_in_bytes`::
  Amount of free physical memory in bytes

`os.mem.free_percent`::
  Percentage of free memory

`os.mem.used_in_bytes`::
  Amount of used physical memory in bytes

`os.mem.used_percent`::
  Percentage of used memory

`os.swap.total_in_bytes`::
  Total amount of swap space in bytes

`os.swap.free_in_bytes`::
  Amount of free swap space in bytes

`os.swap.used_in_bytes`::
  Amount of used swap space in bytes

`os.cgroup.cpuacct.control_group` (Linux only)::
    The `cpuacct` control group to which the Elasticsearch process
    belongs

`os.cgroup.cpuacct.usage_nanos` (Linux only)::
    The total CPU time (in nanoseconds) consumed by all tasks in the
    same cgroup as the Elasticsearch process

`os.cgroup.cpu.control_group` (Linux only)::
    The `cpu` control group to which the Elasticsearch process belongs

`os.cgroup.cpu.cfs_period_micros` (Linux only)::
    The period of time (in microseconds) for how regularly all tasks in
    the same cgroup as the Elasticsearch process should have their
    access to CPU resources reallocated.

`os.cgroup.cpu.cfs_quota_micros` (Linux only)::
    The total amount of time (in microseconds) for which all tasks in
    the same cgroup as the Elasticsearch process can run during one
    period `os.cgroup.cpu.cfs_period_micros`

`os.cgroup.cpu.stat.number_of_elapsed_periods` (Linux only)::
    The number of reporting periods (as specified by
    `os.cgroup.cpu.cfs_period_micros`) that have elapsed

`os.cgroup.cpu.stat.number_of_times_throttled` (Linux only)::
    The number of times all tasks in the same cgroup as the
    Elasticsearch process have been throttled.

`os.cgroup.cpu.stat.time_throttled_nanos` (Linux only)::
    The total amount of time (in nanoseconds) for which all tasks in
    the same cgroup as the Elasticsearch process have been throttled.

`os.cgroup.memory.control_group` (Linux only)::
    The `memory` control group to which the Elasticsearch process
    belongs

`os.cgroup.memory.limit_in_bytes` (Linux only)::
    The maximum amount of user memory (including file cache) allowed
    for all tasks in the same cgroup as the Elasticsearch process.
    This value can be too big to store in a `long`, so is returned as
    a string so that the value returned can exactly match what the
    underlying operating system interface returns. Any value that is
    too large to parse into a `long` almost certainly means no limit
    has been set for the cgroup.

`os.cgroup.memory.usage_in_bytes` (Linux only)::
    The total current memory usage by processes in the cgroup (in bytes)
    by all tasks in the same cgroup as the Elasticsearch process.
    This value is stored as a string for consistency with
    `os.cgroup.memory.limit_in_bytes`.

NOTE: For the cgroup stats to be visible, cgroups must be compiled into
the kernel, the `cpu` and `cpuacct` cgroup subsystems must be
configured and stats must be readable from `/sys/fs/cgroup/cpu`
and `/sys/fs/cgroup/cpuacct`.

[float]
[[process-stats]]
==== Process statistics

The `process` flag can be set to retrieve statistics that concern
the current running process:

`process.timestamp`::
  Last time the process statistics have been refreshed

`process.open_file_descriptors`::
  Number of opened file descriptors associated with the current process, or -1 if not supported

`process.max_file_descriptors`::
  Maximum number of file descriptors allowed on the system, or -1 if not supported

`process.cpu.percent`::
  CPU usage in percent, or -1 if not known at the time the stats are computed

`process.cpu.total_in_millis`::
  CPU time (in milliseconds) used by the process on which the Java virtual machine is running, or -1 if not supported

`process.mem.total_virtual_in_bytes`::
  Size in bytes of virtual memory that is guaranteed to be available to the running process

[float]
[[node-indices-stats]]
=== Indices statistics

You can get information about indices stats on `node`, `indices`, or `shards` level.

[source,js]
--------------------------------------------------
# Fielddata summarised by node
GET /_nodes/stats/indices/fielddata?fields=field1,field2

# Fielddata summarised by node and index
GET /_nodes/stats/indices/fielddata?level=indices&fields=field1,field2

# Fielddata summarised by node, index, and shard
GET /_nodes/stats/indices/fielddata?level=shards&fields=field1,field2

# You can use wildcards for field names
GET /_nodes/stats/indices/fielddata?fields=field*
--------------------------------------------------
// CONSOLE

Supported metrics are:

* `completion`
* `docs`
* `fielddata`
* `flush`
* `get`
* `indexing`
* `merge`
* `query_cache`
* `recovery`
* `refresh`
* `request_cache`
* `search`
* `segments`
* `store`
* `translog`
* `warmer`

[float]
[[search-groups]]
=== Search groups

You can get statistics about search groups for searches executed
on this node.

[source,js]
--------------------------------------------------
# All groups with all stats
GET /_nodes/stats?groups=_all

# Some groups from just the indices stats
GET /_nodes/stats/indices?groups=foo,bar
--------------------------------------------------
// CONSOLE

[float]
[[ingest-stats]]
=== Ingest statistics

The `ingest` flag can be set to retrieve statistics that concern ingest:

`ingest.total.count`::
  The total number of document ingested during the lifetime of this node

`ingest.total.time_in_millis`::
  The total time spent on ingest preprocessing documents during the lifetime of this node

`ingest.total.current`::
  The total number of documents currently being ingested.

`ingest.total.failed`::
  The total number ingest preprocessing operations failed during the lifetime of this node

On top of these overall ingest statistics, these statistics are also provided on a per pipeline basis.

[float]
[[adaptive-selection-stats]]
=== Adaptive selection statistics

The `adaptive_selection` flag can be set to retrieve statistics that concern
<<search-adaptive-replica,adaptive replica selection>>. These statistics are
keyed by node. For each node:

`adaptive_selection.outgoing_searches`::
  The number of outstanding search requests from the node these stats are for to
  the keyed node.

`avg_queue_size`::
  The exponentially weighted moving average queue size of search requests on the
  keyed node.

`avg_service_time_ns`::
  The exponentially weighted moving average service time of search requests on
  the keyed node.

`avg_response_time_ns`::
  The exponentially weighted moving average response time of search requests on
  the keyed node.

`rank`::
  The rank of this node; used for shard selection when routing search requests.

