Process Log Based Metrics

The Process metrics input plugin lets you check how healthy a process is. It does so by performing service checks at specified intervals.

This plugin creates metrics that are log-based, such as JSON payloads. For Prometheus-based metrics, see the Node exporter metrics input plugin.

Configuration parameters

The plugin supports the following configuration parameters:

Key	Description	Default
Proc_Name	The name of the target process to check.	none
Interval_Sec	Specifies the interval between service checks, in seconds.	1
Interval_Nsec	Specifies the interval between service checks, in nanoseconds. This works in conjunction with Interval_Sec.	0
Alert	If enabled, the plugin will only generate messages if the target process is down.	false
Fd	If enabled, a number of fd is appended to each record.	true
Mem	If enabled, memory usage of the process is appended to each record.	true
Threaded	Specifies whether to run this input in its own thread.	false

Get started

To start performing the checks, you can run the plugin from the command line or through the configuration file:

The following example checks the health of crond process.

$ fluent-bit -i proc -p proc_name=crond -o stdout

Configuration file

In your main configuration file, append the following Input & Output sections:

fluent-bit.yaml

pipeline:
    inputs:
        - name: proc
          proc_name: crond
          interval_sec: 1
          interval_nsec: 0
          fd: true
          mem: true

    outputs:
        - name: stdout
          match: '*'

fluent-bit.conf

[INPUT]
    Name          proc
    Proc_Name     crond
    Interval_Sec  1
    Interval_NSec 0
    Fd            true
    Mem           true

[OUTPUT]
    Name   stdout
    Match  *

Testing

After Fluent Bit starts running, it outputs the health of the process:

$ fluent-bit -i proc -p proc_name=fluent-bit -o stdout

Fluent Bit v4.0.3
* Copyright (C) 2015-2025 The Fluent Bit Authors
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

______ _                  _    ______ _ _             ___  _____
|  ___| |                | |   | ___ (_) |           /   ||  _  |
| |_  | |_   _  ___ _ __ | |_  | |_/ /_| |_  __   __/ /| || |/' |
|  _| | | | | |/ _ \ '_ \| __| | ___ \ | __| \ \ / / /_| ||  /| |
| |   | | |_| |  __/ | | | |_  | |_/ / | |_   \ V /\___  |\ |_/ /
\_|   |_|\__,_|\___|_| |_|\__| \____/|_|\__|   \_/     |_(_)___/


[2025/07/01 14:44:47] [ info] [fluent bit] version=4.0.3, commit=f5f5f3c17d, pid=1
[2025/07/01 14:44:47] [ info] [storage] ver=1.5.3, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2025/07/01 14:44:47] [ info] [simd    ] disabled
[2025/07/01 14:44:47] [ info] [cmetrics] version=1.0.3
[2025/07/01 14:44:47] [ info] [ctraces ] version=0.6.6
[2025/07/01 14:44:47] [ info] [input:mem:mem.0] initializing
[2025/07/01 14:44:47] [ info] [input:mem:mem.0] storage_strategy='memory' (memory only)
[2025/07/01 14:44:47] [ info] [sp] stream processor started
[2025/07/01 14:44:47] [ info] [engine] Shutdown Grace Period=5, Shutdown Input Grace Period=2
[2025/07/01 14:44:47] [ info] [output:stdout:stdout.0] worker #0 started
[0] proc.0: [1485780297, {"alive"=>true, "proc_name"=>"fluent-bit", "pid"=>10964, "mem.VmPeak"=>14740000, "mem.VmSize"=>14740000, "mem.VmLck"=>0, "mem.VmHWM"=>1120000, "mem.VmRSS"=>1120000, "mem.VmData"=>2276000, "mem.VmStk"=>88000, "mem.VmExe"=>1768000, "mem.VmLib"=>2328000, "mem.VmPTE"=>68000, "mem.VmSwap"=>0, "fd"=>18}]
[1] proc.0: [1485780298, {"alive"=>true, "proc_name"=>"fluent-bit", "pid"=>10964, "mem.VmPeak"=>14740000, "mem.VmSize"=>14740000, "mem.VmLck"=>0, "mem.VmHWM"=>1148000, "mem.VmRSS"=>1148000, "mem.VmData"=>2276000, "mem.VmStk"=>88000, "mem.VmExe"=>1768000, "mem.VmLib"=>2328000, "mem.VmPTE"=>68000, "mem.VmSwap"=>0, "fd"=>18}]
[2] proc.0: [1485780299, {"alive"=>true, "proc_name"=>"fluent-bit", "pid"=>10964, "mem.VmPeak"=>14740000, "mem.VmSize"=>14740000, "mem.VmLck"=>0, "mem.VmHWM"=>1152000, "mem.VmRSS"=>1148000, "mem.VmData"=>2276000, "mem.VmStk"=>88000, "mem.VmExe"=>1768000, "mem.VmLib"=>2328000, "mem.VmPTE"=>68000, "mem.VmSwap"=>0, "fd"=>18}]
[3] proc.0: [1485780300, {"alive"=>true, "proc_name"=>"fluent-bit", "pid"=>10964, "mem.VmPeak"=>14740000, "mem.VmSize"=>14740000, "mem.VmLck"=>0, "mem.VmHWM"=>1152000, "mem.VmRSS"=>1148000, "mem.VmData"=>2276000, "mem.VmStk"=>88000, "mem.VmExe"=>1768000, "mem.VmLib"=>2328000, "mem.VmPTE"=>68000, "mem.VmSwap"=>0, "fd"=>18}]