[discrete]
[[monitoring]]
== APIs for monitoring {ls}

{ls} provides monitoring APIs for retrieving runtime metrics
about {ls}:

* <<node-info-api>>
* <<plugins-api>>
* <<node-stats-api>>
* <<hot-threads-api>>


You can use the root resource to retrieve general information about the Logstash instance, including
the host and version.

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/?pretty'
--------------------------------------------------

Example response:

[source,json,subs="attributes"]
--------------------------------------------------
{
   "host": "skywalker",
   "version": "{logstash_version}",
   "http_address": "127.0.0.1:9600"
}
--------------------------------------------------

NOTE: By default, the monitoring API attempts to bind to `tcp:9600`. If this port is already in use by another Logstash
instance, you need to launch Logstash with the `--api.http.port` flag specified to bind to a different port. See
<<command-line-flags>> for more information.

[discrete]
[[monitoring-api-security]]
==== Securing the Logstash API

The {ls} Monitoring APIs are not secured by default, but you can configure {ls} to secure them in one of several ways to meet your organization's needs.

You can enable SSL for the Logstash API by setting `api.ssl.enabled: true` in the `logstash.yml`, and providing the relevant keystore settings `api.ssl.keystore.path` and `api.ssl.keystore.password`:

[source]
--------------------------------------------------
api.ssl.enabled: true
api.ssl.keystore.path: /path/to/keystore.jks
api.ssl.keystore.password: "s3cUr3p4$$w0rd"
--------------------------------------------------

The keystore must be in either jks or p12 format, and must contain both a certificate and a private key.
Connecting clients receive this certificate, allowing them to authenticate the Logstash endpoint.

You can also require HTTP Basic authentication by setting `api.auth.type: basic` in the `logstash.yml`, and providing the relevant credentials `api.auth.basic.username` and `api.auth.basic.password`:

[source]
--------------------------------------------------
api.auth.type: basic
api.auth.basic.username: "logstash"
api.auth.basic.password: "s3cUreP4$$w0rD"
--------------------------------------------------

NOTE: Usage of Keystore or Environment or variable replacements is encouraged for password-type fields to avoid storing them in plain text.
      For example, specifying the value `"${HTTP_PASS}"` will resolve to the value stored in the <<keystore,secure keystore's>> `HTTP_PASS` variable if present or the same variable from the <<environment-variables,environment>>)

[discrete]
[[monitoring-common-options]]
==== Common options

The following options can be applied to all of the Logstash monitoring APIs.

[discrete]
===== Pretty results

When appending `?pretty=true` to any request made, the JSON returned
will be pretty formatted (use it for debugging only!).

[discrete]
===== Human-readable output

NOTE: For Logstash {logstash_version}, the `human` option is supported for the <<hot-threads-api>>
only. When you specify `human=true`, the results are returned in plain text instead of
JSON format. The default is false.

Statistics are returned in a format suitable for humans
(eg `"exists_time": "1h"` or `"size": "1kb"`) and for computers
(eg `"exists_time_in_millis": 3600000` or `"size_in_bytes": 1024`).
The human-readable values can be turned off by adding `?human=false`
to the query string. This makes sense when the stats results are
being consumed by a monitoring tool, rather than intended for human
consumption.  The default for the `human` flag is
`false`.


[[node-info-api]]
=== Node Info API

The node info API retrieves information about the node.

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/<types>'
--------------------------------------------------

Where `<types>` is optional and specifies the types of node info you want to return.

You can limit the info that's returned by combining any of the following types in a comma-separated list:

[horizontal]
<<node-pipeline-info,`pipelines`>>::
Gets pipeline-specific information and settings for each pipeline.
<<node-os-info,`os`>>::
Gets node-level info about the OS.
<<node-jvm-info,`jvm`>>::
Gets node-level JVM info, including info about threads.

See <<monitoring-common-options, Common Options>> for a list of options that can be applied to all
Logstash monitoring APIs.

[discrete]
[[node-pipeline-info]]
===== Pipeline info

The following request returns a JSON document that shows pipeline info, such as the number of workers,
batch size, and batch delay:

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/pipelines?pretty'
--------------------------------------------------

If you want to view additional information about a pipeline, such as stats for each configured input, filter,
or output stage, see the <<pipeline-stats>> section under the <<node-stats-api>>.

Example response:

[source,json,subs="attributes"]
--------------------------------------------------
{
  "pipelines" : {
    "test" : {
      "workers" : 1,
      "batch_size" : 1,
      "batch_delay" : 5,
      "config_reload_automatic" : false,
      "config_reload_interval" : 3
    },
    "test2" : {
      "workers" : 8,
      "batch_size" : 125,
      "batch_delay" : 5,
      "config_reload_automatic" : false,
      "config_reload_interval" : 3
    }
  }
}
--------------------------------------------------

You can see the info for a specific pipeline by including the pipeline ID. In
the following example, the ID of the pipeline is `test`:

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/pipelines/test?pretty'
--------------------------------------------------

Example response:

[source,json]
----------
{
  "pipelines" : {
    "test" : {
      "workers" : 1,
      "batch_size" : 1,
      "batch_delay" : 5,
      "config_reload_automatic" : false,
      "config_reload_interval" : 3
    }
  }
}
----------

If you specify an invalid pipeline ID, the request returns a 404 Not Found error.

[discrete]
[[node-os-info]]
==== OS info

The following request returns a JSON document that shows the OS name, architecture, version, and
available processors:

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/os?pretty'
--------------------------------------------------

Example response:

[source,json]
--------------------------------------------------
{
  "os": {
    "name": "Mac OS X",
    "arch": "x86_64",
    "version": "10.12.4",
    "available_processors": 8
  }
}
--------------------------------------------------

[discrete]
[[node-jvm-info]]
==== JVM info

The following request returns a JSON document that shows node-level JVM stats, such as the JVM process id, version,
VM info, memory usage, and info about garbage collectors:

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/jvm?pretty'
--------------------------------------------------

Example response:

[source,json]
--------------------------------------------------
{
  "jvm": {
    "pid": 59616,
    "version": "1.8.0_65",
    "vm_name": "Java HotSpot(TM) 64-Bit Server VM",
    "vm_version": "1.8.0_65",
    "vm_vendor": "Oracle Corporation",
    "start_time_in_millis": 1484251185878,
    "mem": {
      "heap_init_in_bytes": 268435456,
      "heap_max_in_bytes": 1037959168,
      "non_heap_init_in_bytes": 2555904,
      "non_heap_max_in_bytes": 0
    },
    "gc_collectors": [
      "ParNew",
      "ConcurrentMarkSweep"
    ]
  }
}
--------------------------------------------------


[[plugins-api]]
=== Plugins info API

The plugins info API gets information about all Logstash plugins that are currently installed.
This API basically returns the output of running the `bin/logstash-plugin list --verbose` command.

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/plugins?pretty'
--------------------------------------------------

See <<monitoring-common-options, Common Options>> for a list of options that can be applied to all
Logstash monitoring APIs.

The output is a JSON document.

Example response:

["source","js",subs="attributes"]
--------------------------------------------------
{
  "total": 93,
  "plugins": [
    {
      "name": "logstash-codec-cef",
      "version": "4.1.2"
    },
    {
      "name": "logstash-codec-collectd",
      "version": "3.0.3"
    },
    {
      "name": "logstash-codec-dots",
      "version": "3.0.2"
    },
    {
      "name": "logstash-codec-edn",
      "version": "3.0.2"
    },
    .
    .
    .
  ]
--------------------------------------------------


[[node-stats-api]]
=== Node Stats API

The node stats API retrieves runtime stats about Logstash.

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/stats/<types>'
--------------------------------------------------

Where `<types>` is optional and specifies the types of stats you want to return.

By default, all stats are returned. You can limit the info that's returned by combining any of the following types in a comma-separated list:

[horizontal]
<<jvm-stats,`jvm`>>::
Gets JVM stats, including stats about threads, memory usage, garbage collectors,
and uptime.
<<process-stats,`process`>>::
Gets process stats, including stats about file descriptors, memory consumption, and CPU usage.
<<event-stats,`events`>>::
Gets event-related statistics for the Logstash instance (regardless of how many
pipelines were created and destroyed).
<<flow-stats,`flow`>>::
Gets flow-related statistics for the Logstash instance (regardless of how many
pipelines were created and destroyed).
<<pipeline-stats,`pipelines`>>::
Gets runtime stats about each Logstash pipeline.
<<reload-stats,`reloads`>>::
Gets runtime stats about config reload successes and failures.
<<os-stats,`os`>>::
Gets runtime stats about cgroups when Logstash is running in a container.
<<geoip-database-stats,`geoip_download_manager`>>::
Gets stats for databases used with the <<plugins-filters-geoip, Geoip filter plugin>>.

See <<monitoring-common-options, Common Options>> for a list of options that can be applied to all
Logstash monitoring APIs.

[discrete]
[[jvm-stats]]
==== JVM stats

The following request returns a JSON document containing JVM stats:

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/stats/jvm?pretty'
--------------------------------------------------

Example response:

[source,json]
--------------------------------------------------
{
  "jvm" : {
    "threads" : {
      "count" : 49,
      "peak_count" : 50
    },
    "mem" : {
      "heap_used_percent" : 14,
      "heap_committed_in_bytes" : 309866496,
      "heap_max_in_bytes" : 1037959168,
      "heap_used_in_bytes" : 151686096,
      "non_heap_used_in_bytes" : 122486176,
      "non_heap_committed_in_bytes" : 133222400,
      "pools" : {
        "survivor" : {
          "peak_used_in_bytes" : 8912896,
          "used_in_bytes" : 288776,
          "peak_max_in_bytes" : 35782656,
          "max_in_bytes" : 35782656,
          "committed_in_bytes" : 8912896
        },
        "old" : {
          "peak_used_in_bytes" : 148656848,
          "used_in_bytes" : 148656848,
          "peak_max_in_bytes" : 715849728,
          "max_in_bytes" : 715849728,
          "committed_in_bytes" : 229322752
        },
        "young" : {
          "peak_used_in_bytes" : 71630848,
          "used_in_bytes" : 2740472,
          "peak_max_in_bytes" : 286326784,
          "max_in_bytes" : 286326784,
          "committed_in_bytes" : 71630848
        }
      }
    },
    "gc" : {
      "collectors" : {
        "old" : {
          "collection_time_in_millis" : 607,
          "collection_count" : 12
        },
        "young" : {
          "collection_time_in_millis" : 4904,
          "collection_count" : 1033
        }
      }
    },
    "uptime_in_millis" : 1809643
  }
}
--------------------------------------------------

[discrete]
[[process-stats]]
==== Process stats

The following request returns a JSON document containing process stats:

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/stats/process?pretty'
--------------------------------------------------

Example response:

[source,json]
--------------------------------------------------
{
  "process" : {
    "open_file_descriptors" : 184,
    "peak_open_file_descriptors" : 185,
    "max_file_descriptors" : 10240,
    "mem" : {
      "total_virtual_in_bytes" : 5486125056
    },
    "cpu" : {
      "total_in_millis" : 657136,
      "percent" : 2,
      "load_average" : {
        "1m" : 2.38134765625
      }
    }
  }
}
--------------------------------------------------

[discrete]
[[event-stats]]
==== Event stats

The following request returns a JSON document containing event-related statistics
for the Logstash instance:

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/stats/events?pretty'
--------------------------------------------------

Example response:

[source,json]
--------------------------------------------------
{
  "events" : {
    "in" : 293658,
    "filtered" : 293658,
    "out" : 293658,
    "duration_in_millis" : 2324391,
    "queue_push_duration_in_millis" : 343816
  }
--------------------------------------------------

[discrete]
[[flow-stats]]
==== Flow stats

The following request returns a JSON document containing flow-rates
for the Logstash instance:

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/stats/flow?pretty'
--------------------------------------------------

Example response:

[source,json]
--------------------------------------------------
{
  "flow" : {
    "input_throughput" : {
      "current": 189.720,
      "lifetime": 201.841
    },
    "filter_throughput" : {
      "current": 187.810,
      "lifetime": 201.799
    },
    "output_throughput" : {
      "current": 191.087,
      "lifetime": 201.761
    },
    "queue_backpressure" : {
      "current": 0.277,
      "lifetime": 0.031
    },
    "worker_concurrency" : {
      "current": 1.973,
      "lifetime": 1.721
    },
    "worker_utilization" : {
      "current": 49.32,
      "lifetime": 43.02
    }
  }
}
--------------------------------------------------

NOTE: When the rate for a given flow metric window is infinite, it is presented as a string (either `"Infinity"` or  `"-Infinity"`).
      This occurs when the numerator metric has changed during the window without a change in the rate's denominator metric.

Flow rates provide visibility into how a Logstash instance or an individual pipeline is _currently_ performing relative to _itself_ over time.
This allows us to attach _meaning_ to the cumulative-value metrics that are also presented by this API, and to determine whether an instance or pipeline is behaving better or worse than it has in the past.

The following flow rates are available for the logstash process as a whole and for each of its pipelines individually.
In addition, pipelines may have <<pipeline-flow-rates, additional flow rates>> depending on their configuration.


[%autowidth.stretch, cols="1m,4"]
|===
|Flow Rate | Definition

| input_throughput |
This metric is expressed in events-per-second, and is the rate of events being pushed into the pipeline(s) queue(s) relative to wall-clock time (`events.in` / second).
It includes events that are blocked by the queue and have not yet been accepted.

| filter_throughput |
This metric is expressed in events-per-second, and is the rate of events flowing through the filter phase of the pipeline(s) relative to wall-clock time (`events.filtered` / second).

| output_throughput |
This metric is expressed in events-per-second, and is the rate of events flowing through the output phase of the pipeline(s) relative to wall-clock time (`events.out` / second).

| worker_concurrency |
This is a unitless metric representing the cumulative time spent by all workers relative to wall-clock time (`duration_in_millis` / millisecond).

A _pipeline_ is considered "saturated" when its `worker_concurrency` flow metric approaches its available `pipeline.workers`, because it indicates that all of its available workers are being kept busy.
Tuning a saturated pipeline to have more workers can often work to increase that pipeline's throughput and decrease back-pressure to its queue, unless the pipeline is experiencing back-pressure from its outputs.

A _process_ is also considered "saturated" when its top-level `worker_concurrency` flow metric approaches the _cumulative_ `pipeline.workers` across _all_ pipelines, and similarly can be addressed by tuning the <<pipeline-stats,individual pipelines>> that are saturated.

| worker_utilization |

This is a unitless metric that indicates the percentage of available worker time being used by all plugins in a given pipeline (`duration` / (`uptime` * `pipeline.workers`).
It is useful for determining whether the pipeline has consistently-idle resources or is under resource contention.

A _pipeline_ is considered "saturated" when its `worker_utilization` flow metric approaches 100, because it indicates that all of its workers are being kept busy.
This is typically an indication of either downstream back-pressure or insufficient resources allocated to the pipeline.
Tuning a saturated pipeline to have more workers can often work to increase that pipeline's throughput and decrease back-pressure to its queue, unless the pipeline is experiencing back-pressure from its outputs.

A _pipeline_ is considered "starved" when its `worker_utilization` flow metric approaches 0, because it indicates that none of its workers are being kept busy.
This is typically an indication that the inputs are not receiving or retrieving enough volume to keep the pipeline workers busy.
Tuning a starved pipeline to have fewer workers can help it to consume less memory and CPU, freeing up resources for other pipelines.

| queue_backpressure |
This is a unitless metric representing the cumulative time spent by all inputs blocked pushing events into their pipeline's queue, relative to wall-clock time (`queue_push_duration_in_millis` / millisecond).
It is typically most useful when looking at the stats for an <<pipeline-stats,individual pipeline>>.

While a "zero" value indicates no back-pressure to the queue, the magnitude of this metric is highly dependent on the _shape_ of the pipelines and their inputs.
It cannot be used to compare one pipeline to another or even one process to _itself_ if the quantity or shape of its pipelines changes.
A pipeline with only one single-threaded input may contribute up to 1.00, a pipeline whose inputs have hundreds of inbound connections may contribute much higher numbers to this combined value.

Additionally, some amount of back-pressure is both _normal_ and _expected_ for pipelines that are _pulling_ data, as this back-pressure allows them to slow down and pull data at a rate its downstream pipeline can tolerate.
|===

Each flow stat includes rates for one or more recent windows of time:

// Templates for short-hand notes in the table below
:flow-stable: pass:quotes[*Stable*]
:flow-preview: pass:quotes[_Technology Preview_]

[%autowidth.stretch, cols="1m,2,4"]
|===
| Flow Window     | Availability   | Definition

| current         | {flow-stable}  | the most recent ~10s
| lifetime        | {flow-stable}  | the lifetime of the relevant pipeline or process
| last_1_minute   | {flow-preview} | the most recent ~1 minute
| last_5_minutes  | {flow-preview} | the most recent ~5 minutes
| last_15_minutes | {flow-preview} | the most recent ~15 minutes
| last_1_hour     | {flow-preview} | the most recent ~1 hour
| last_24_hours   | {flow-preview} | the most recent ~24 hours

|===

NOTE: The flow rate windows marked as "Technology Preview" are subject to change without notice.
      Future releases of {ls} may include more, fewer, or different windows for each rate in response to community feedback.

[discrete]
[[pipeline-stats]]
==== Pipeline stats

The following request returns a JSON document containing pipeline stats,
including:

* the number of events that were input, filtered, or output by each pipeline
* the current and lifetime <<flow-stats,_flow_ rates>> for each pipeline
* stats for each configured filter or output stage
* info about config reload successes and failures
(when <<reloading-config,config reload>> is enabled)
* info about the persistent queue (when <<persistent-queues,persistent queues>> are enabled)

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/stats/pipelines?pretty'
--------------------------------------------------

Example response:

[source,json]
--------------------------------------------------
{
  "pipelines" : {
    "test" : {
      "events" : {
        "duration_in_millis" : 365495,
        "in" : 216610,
        "filtered" : 216485,
        "out" : 216485,
        "queue_push_duration_in_millis" : 342466
      },
      "flow" : {
        "input_throughput" : {
          "current" : 603.1,
          "lifetime" : 575.4
        },
        "filter_throughput" : {
          "current" : 604.2,
          "lifetime" : 575.1
        },
        "output_throughput" : {
          "current" : 604.8,
          "lifetime" : 575.1
        },
        "queue_backpressure" : {
          "current" : 0.214,
          "lifetime" : 0.937
        },
        "worker_concurrency" : {
          "current" : 0.941,
          "lifetime" : 0.9709
        },
        "worker_utilization" : {
          "current" : 93.092,
          "lifetime" : 92.187
        }
      },
      "plugins" : {
        "inputs" : [ {
          "id" : "35131f351e2dc5ed13ee04265a8a5a1f95292165-1",
          "events" : {
            "out" : 216485,
            "queue_push_duration_in_millis" : 342466
          },
          "flow" : {
            "throughput" : {
              "current" : 603.1,
              "lifetime" : 590.7
            }
          },
          "name" : "beats"
        } ],
        "filters" : [ {
          "id" : "35131f351e2dc5ed13ee04265a8a5a1f95292165-2",
          "events" : {
            "duration_in_millis" : 55969,
            "in" : 216485,
            "out" : 216485
          },
          "failures" : 216485,
          "patterns_per_field" : {
            "message" : 1
          },
          "flow" : {
            "worker_utilization" : {
              "current" : 16.71,
              "lifetime" : 15.27
            },
            "worker_millis_per_event" : {
              "current" : 2829,
              "lifetime" : 0.2585
            }
          },
          "name" : "grok"
        }, {
          "id" : "35131f351e2dc5ed13ee04265a8a5a1f95292165-3",
          "events" : {
            "duration_in_millis" : 3326,
            "in" : 216485,
            "out" : 216485
          },
          "flow" : {
            "worker_utilization" : {
              "current" : 1.042,
              "lifetime" : 0.9076
            },
            "worker_millis_per_event" : {
              "current" : 0.01763,
              "lifetime" : 0.01536
            }
          },
          "name" : "geoip"
        } ],
        "outputs" : [ {
          "id" : "35131f351e2dc5ed13ee04265a8a5a1f95292165-4",
          "events" : {
            "duration_in_millis" : 278557,
            "in" : 216485,
            "out" : 216485
          },
          "flow" : {
            "worker_utilization" : {
              "current" : 75.34,
              "lifetime" : 76.01
            },
            "worker_millis_per_event" : {
              "current" : 1.276,
              "lifetime" : 1.287
            }
          },
          "name" : "elasticsearch"
        } ]
      },
      "reloads" : {
        "last_error" : null,
        "successes" : 0,
        "last_success_timestamp" : null,
        "last_failure_timestamp" : null,
        "failures" : 0
      },
      "queue" : {
        "type" : "memory"
      }
    },
    "test2" : {
      "events" : {
        "duration_in_millis" : 2222229,
        "in" : 87247,
        "filtered" : 87247,
        "out" : 87247,
        "queue_push_duration_in_millis" : 1532
      },
      "flow" : {
        "input_throughput" : {
          "current" : 301.7,
          "lifetime" : 231.8
        },
        "filter_throughput" : {
          "current" : 207.2,
          "lifetime" : 231.8
        },
        "output_throughput" : {
          "current" : 207.2,
          "lifetime" : 231.8
        },
        "queue_backpressure" : {
          "current" : 0.735,
          "lifetime" : 0.0006894
        },
        "worker_concurrency" : {
          "current" : 8.0,
          "lifetime" : 5.903
        },
        "worker_utilization" : {
          "current" : 100,
          "lifetime" : 75.8
        }
      },
      "plugins" : {
        "inputs" : [ {
          "id" : "d7ea8941c0fc48ac58f89c84a9da482107472b82-1",
          "events" : {
            "out" : 87247,
            "queue_push_duration_in_millis" : 1532
          },
          "flow" : {
            "throughput" : {
              "current" : 301.7,
              "lifetime" : 238.1
            }
          },
          "name" : "twitter"
        } ],
        "filters" : [ ],
        "outputs" : [ {
          "id" : "d7ea8941c0fc48ac58f89c84a9da482107472b82-2",
          "events" : {
            "duration_in_millis" : 2222229,
            "in" : 87247,
            "out" : 87247
          },
          "flow" : {
            "worker_utilization" : {
              "current" : 100,
              "lifetime" : 75.8
            },
            "worker_millis_per_event" : {
              "current" : 33.6,
              "lifetime" : 25.47
            }
          },
          "name" : "elasticsearch"
        } ]
      },
      "reloads" : {
        "last_error" : null,
        "successes" : 0,
        "last_success_timestamp" : null,
        "last_failure_timestamp" : null,
        "failures" : 0
      },
      "queue" : {
        "type" : "memory"
      }
    }
  }
}
--------------------------------------------------

You can see the stats for a specific pipeline by including the pipeline ID. In
the following example, the ID of the pipeline is `test`:

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/stats/pipelines/test?pretty'
--------------------------------------------------

Example response:

[source,json]
--------------------------------------------------
{
  "pipelines" : {
    "test" : {
      "events" : {
        "duration_in_millis" : 365495,
        "in" : 216485,
        "filtered" : 216485,
        "out" : 216485,
        "queue_push_duration_in_millis" : 2283
      },
      "flow" : {
        "input_throughput" : {
          "current" : 871.3,
          "lifetime" : 575.1
        },
        "filter_throughput" : {
          "current" : 874.8,
          "lifetime" : 575.1
        },
        "output_throughput" : {
          "current" : 874.8,
          "lifetime" : 575.1
        },
        "queue_backpressure" : {
          "current" : 0,
          "lifetime" : 0.006246
        },
        "worker_concurrency" : {
          "current" : 1.471,
          "lifetime" : 0.9709
        },
        "worker_utilization" : {
          "current" : 74.54,
          "lifetime" : 46.10
        },
        "queue_persisted_growth_bytes" : {
          "current" : 8731,
          "lifetime" : 0.0106
        },
        "queue_persisted_growth_events" : {
          "current" : 0.0,
          "lifetime" : 0.0
        }
      },
      "plugins" : {
        "inputs" : [ {
          "id" : "35131f351e2dc5ed13ee04265a8a5a1f95292165-1",
          "events" : {
            "out" : 216485,
            "queue_push_duration_in_millis" : 2283
          },
          "flow" : {
            "throughput" : {
              "current" : 871.3,
              "lifetime" : 590.7
            }
          },
          "name" : "beats"
        } ],
        "filters" : [ {
          "id" : "35131f351e2dc5ed13ee04265a8a5a1f95292165-2",
          "events" : {
            "duration_in_millis" : 55969,
            "in" : 216485,
            "out" : 216485
          },
          "failures" : 216485,
          "patterns_per_field" : {
            "message" : 1
          },
          "flow" : {
            "worker_utilization" : {
              "current" : 10.53,
              "lifetime" : 7.636
            },
            "worker_millis_per_event" : {
              "current" : 0.3565,
              "lifetime" : 0.2585
            }
          },
          "name" : "grok"
        }, {
          "id" : "35131f351e2dc5ed13ee04265a8a5a1f95292165-3",
          "events" : {
            "duration_in_millis" : 3326,
            "in" : 216485,
            "out" : 216485
          },
          "name" : "geoip",
          "flow" : {
            "worker_utilization" : {
              "current" : 1.743,
              "lifetime" : 0.4538
            },
            "worker_millis_per_event" : {
              "current" : 0.0590,
              "lifetime" : 0.01536
            }
          }
        } ],
        "outputs" : [ {
          "id" : "35131f351e2dc5ed13ee04265a8a5a1f95292165-4",
          "events" : {
            "duration_in_millis" : 278557,
            "in" : 216485,
            "out" : 216485
          },
          "flow" : {
            "worker_utilization" : {
              "current" : 62.27,
              "lifetime" : 38.01
            },
            "worker_millis_per_event" : {
              "current" : 2.109,
              "lifetime" : 1.287
            }
          },
          "name" : "elasticsearch"
        } ]
      },
      "reloads" : {
        "last_error" : null,
        "successes" : 0,
        "last_success_timestamp" : null,
        "last_failure_timestamp" : null,
        "failures" : 0
      },
      "queue": {
        "type" : "persisted",
        "capacity": {
          "max_unread_events": 0,
          "page_capacity_in_bytes": 67108864,
          "max_queue_size_in_bytes": 1073741824,
          "queue_size_in_bytes": 3885
        },
        "data": {
          "path": "/pipeline/queue/path",
          "free_space_in_bytes": 936886480896,
          "storage_type": "apfs"
        },
        "events": 0,
        "events_count": 0,
        "queue_size_in_bytes": 3885,
        "max_queue_size_in_bytes": 1073741824
      }
    }
  }
}
--------------------------------------------------

[discrete]
[[pipeline-flow-rates]]
===== Pipeline flow rates

Each pipeline's entry in the API response includes a number of pipeline-scoped <<flow-stats,_flow_ rates>> such as `input_throughput`, `worker_concurrency`, and `queue_backpressure` to provide visibility into the flow of events through the pipeline.

When configured with a <<persistent-queues,persistent queue>>, the pipeline's `flow` will include additional rates to provide visibility into the health of the pipeline's persistent queue:

[%autowidth.stretch, cols="1m,4"]
|===
|Flow Rate | Definition

| queue_persisted_growth_events |
This metric is expressed in events-per-second, and is the rate of change of the number of unacknowleged events in the queue, relative to wall-clock time (`queue.events_count` / second).
A positive number indicates that the queue's event-count is growing, and a negative number indicates that the queue is shrinking.

| queue_persisted_growth_bytes |
This metric is expressed in bytes-per-second, and is the rate of change of the size of the persistent queue on disk, relative to wall-clock time (`queue.queue_size_in_bytes` / second).
A positive number indicates that the queue size-on-disk is growing, and a negative number indicates that the queue is shrinking.

NOTE: The size of a PQ on disk includes both unacknowledged events and previously-acknowledged events from pages that contain one or more unprocessed events.
      This means it grows gradually as individual events are added, but shrinks in large chunks each time a whole page of processed events is reclaimed (read more: <<garbage-collection, PQ disk garbage collection>>).
|===

[discrete]
[[plugin-flow-rates]]
===== Plugin flow rates

Several additional plugin-level flow rates are available, and can be helpful for identifying problems with individual plugins:

[%autowidth.stretch, cols="2m,1,4"]
|===
| Flow Rate | Plugin Types | Definition

| throughput | Inputs |
This metric is expressed in events-per-second, and is the rate of events this input plugin is pushing into the pipeline's queue relative to wall-clock time (`events.in` / `second`).
It includes events that are blocked by the queue and have not yet been accepted.

| worker_utilization | Filters, Outputs |
This is a unitless metric that indicates the percentage of available worker time being used by this individual plugin (`duration` / (`uptime` * `pipeline.workers`).
It is useful for identifying which plugins in a pipeline are using the available worker resources.

| worker_millis_per_event | Filters, Outputs |
This metric is expressed in worker-millis-spent-per-event (`duration_in_millis` / `events.in`) with higher scores indicating more resources spent per event.
It is especially useful for identifying issues with plugins that operate on a small subset of events.
An `"Infinity"` value for a given flow window indicates that worker millis have been spent without any events completing processing; this can indicate a plugin that is either stuck or handling only empty batches.

|===
[discrete]
[[reload-stats]]
==== Reload stats

The following request returns a JSON document that shows info about config reload successes and failures.

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/stats/reloads?pretty'
--------------------------------------------------

Example response:

[source,js]
--------------------------------------------------
{
  "reloads": {
    "successes": 0,
    "failures": 0
  }
}
--------------------------------------------------

[discrete]
[[os-stats]]
==== OS stats

When Logstash is running in a container, the following request returns a JSON document that
contains cgroup information to give you a more accurate view of CPU load, including whether
the container is being throttled.

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/stats/os?pretty'
--------------------------------------------------

Example response:

[source,json]
--------------------------------------------------
{
  "os" : {
    "cgroup" : {
      "cpuacct" : {
        "control_group" : "/elastic1",
        "usage_nanos" : 378477588075
                },
      "cpu" : {
        "control_group" : "/elastic1",
        "cfs_period_micros" : 1000000,
        "cfs_quota_micros" : 800000,
        "stat" : {
          "number_of_elapsed_periods" : 4157,
          "number_of_times_throttled" : 460,
          "time_throttled_nanos" : 581617440755
        }
      }
    }
  }
}
--------------------------------------------------

[discrete]
[[geoip-database-stats]]
==== Geoip database stats

You can monitor stats for the geoip databases used with the <<plugins-filters-geoip, Geoip filter plugin>>.

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/stats/geoip_download_manager?pretty'
--------------------------------------------------

For more info, see <<plugins-filters-geoip-metrics,Database Metrics>> in the Geoip filter plugin docs. 

[[hot-threads-api]]
=== Hot Threads API

The hot threads API gets the current hot threads for Logstash. A hot thread is a
Java thread that has high CPU usage and executes for a longer than normal period
of time.

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/hot_threads?pretty'
--------------------------------------------------

The output is a JSON document that contains a breakdown of the top hot threads for
Logstash.

Example response:

[source,json,subs="attributes"]
--------------------------------------------------
{
  "hot_threads" : {
    "time" : "2017-06-06T18:25:28-07:00",
    "busiest_threads" : 3,
    "threads" : [ {
      "name" : "Ruby-0-Thread-7",
      "percent_of_cpu_time" : 0.0,
      "state" : "timed_waiting",
      "path" : "/path/to/logstash-{logstash_version}/vendor/bundle/jruby/1.9/gems/puma-2.16.0-java/lib/puma/thread_pool.rb:187",
      "traces" : [ "java.lang.Object.wait(Native Method)", "org.jruby.RubyThread.sleep(RubyThread.java:1002)", "org.jruby.RubyKernel.sleep(RubyKernel.java:803)" ]
    }, {
      "name" : "[test2]>worker3",
      "percent_of_cpu_time" : 0.85,
      "state" : "waiting",
      "traces" : [ "sun.misc.Unsafe.park(Native Method)", "java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)", "java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836)" ]
    }, {
      "name" : "[test2]>worker2",
      "percent_of_cpu_time" : 0.85,
      "state" : "runnable",
      "traces" : [ "org.jruby.RubyClass.allocate(RubyClass.java:225)", "org.jruby.RubyClass.newInstance(RubyClass.java:856)", "org.jruby.RubyClass$INVOKER$i$newInstance.call(RubyClass$INVOKER$i$newInstance.gen)" ]
    } ]
  }
}
--------------------------------------------------

The parameters allowed are:

[horizontal]
`threads`:: 	        The number of hot threads to return. The default is 10.
`stacktrace_size`::     The depth of the stack trace to report for each thread. The default is 50.
`human`:: 	            If true, returns plain text instead of JSON format. The default is false.
`ignore_idle_threads`:: If true, does not return idle threads. The default is true.

See <<monitoring-common-options, Common Options>> for a list of options that can be applied to all
Logstash monitoring APIs.

You can use the `?human` parameter to return the document in a human-readable format.

[source,js]
--------------------------------------------------
curl -XGET 'localhost:9600/_node/hot_threads?human=true'
--------------------------------------------------

Example of a human-readable response:

[source%nowrap,text,subs="attributes"]
--------------------------------------------------
 ::: {}
 Hot threads at 2017-06-06T18:31:17-07:00, busiestThreads=3:
 ================================================================================
 0.0 % of cpu usage, state: timed_waiting, thread name: 'Ruby-0-Thread-7'
 /path/to/logstash-{logstash_version}/vendor/bundle/jruby/1.9/gems/puma-2.16.0-java/lib/puma/thread_pool.rb:187
	 java.lang.Object.wait(Native Method)
	 org.jruby.RubyThread.sleep(RubyThread.java:1002)
	 org.jruby.RubyKernel.sleep(RubyKernel.java:803)
 --------------------------------------------------------------------------------
 0.0 % of cpu usage, state: waiting, thread name: 'defaultEventExecutorGroup-5-4'
	 sun.misc.Unsafe.park(Native Method)
	 java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
	 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
 --------------------------------------------------------------------------------
 0.05 % of cpu usage, state: timed_waiting, thread name: '[test]-pipeline-manager'
	 java.lang.Object.wait(Native Method)
	 java.lang.Thread.join(Thread.java:1253)
	 org.jruby.internal.runtime.NativeThread.join(NativeThread.java:75)

--------------------------------------------------
