Health

The Health input plugin lets you check how healthy a TCP server is. It checks by issuing a TCP connection at regular intervals.

Configuration parameters

The plugin supports the following configuration parameters:

Key	Description	Default
Host	Name of the target host or IP address.	none
Port	TCP port where to perform the connection request.	none
Interval_Sec	Interval in seconds between the service checks.	1
Internal_Nsec	Specify a nanoseconds interval for service checks. Works in conjunction with the Interval_Sec configuration key.	0
Alert	If enabled, it generates messages if the target TCP service is down.	false
Add_Host	If enabled, hostname is appended to each records.	false
Add_Port	If enabled, port number is appended to each records.	false
Threaded	Indicates 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:

Command line

From the command line you can let Fluent Bit generate the checks with the following options:

$ fluent-bit -i health -p host=127.0.0.1 -p port=80 -o stdout

Configuration file

In your main configuration file append the following:

fluent-bit.yaml

pipeline:
    inputs:
        - name: health
          host: 127.0.0.1
          port: 80
          interval_sec: 1
          interval_nsec: 0
          
    outputs:
        - name: stdout
          match: '*'

fluent-bit.conf

[INPUT]
    Name          health
    Host          127.0.0.1
    Port          80
    Interval_Sec  1
    Interval_NSec 0

[OUTPUT]
    Name   stdout
    Match  *

Testing

Once Fluent Bit is running, you will see some random values in the output interface similar to this:

$ fluent-bit -i health -p host=127.0.0.1 -p port=80 -o stdout

Fluent Bit v4.0.0
* Copyright (C) 2015-2025 The Fluent Bit Authors
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

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


[2025/06/30 16:12:06] [ info] [fluent bit] version=4.0.0, commit=3a91b155d6, pid=91577
[2025/06/30 16:12:06] [ info] [storage] ver=1.5.2, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2025/06/30 16:12:06] [ info] [simd    ] disabled
[2025/06/30 16:12:06] [ info] [cmetrics] version=0.9.9
[2025/06/30 16:12:06] [ info] [ctraces ] version=0.6.2
[2025/06/30 16:12:06] [ info] [input:health:health.0] initializing
[2025/06/30 16:12:06] [ info] [input:health:health.0] storage_strategy='memory' (memory only)
[2025/06/30 16:12:06] [ info] [sp] stream processor started
[2025/06/30 16:12:06] [ info] [output:stdout:stdout.0] worker #0 started
[0] health.0: [1624145988.305640385, {"alive"=>true}]
[1] health.0: [1624145989.305575360, {"alive"=>true}]
[2] health.0: [1624145990.306498573, {"alive"=>true}]
[3] health.0: [1624145991.305595498, {"alive"=>true}]