Image Overview: fluentd

Overview: fluentd Chainguard Image

Fluentd: Unified Logging Layer (project under CNCF)

Download this Image

The image is available on

docker pull

Using fluentd

Run a Fluentd instance that will receive messages over TCP port 24224 through the Forward protocol, and send the messages to the STDOUT interface in JSON format

Run the fluentd container and mount the fluent.conf in examples/

docker run --rm -p -v ${PWD}/examples/basic_docker.conf:/etc/fluent/fluent.conf

In another terminal try sending some logs to fluentd with another container

docker run --rm --log-driver=fluentd --log-opt tag="docker.{{.ID}}" echo 'Hello Fluentd!'

The Fluentd container should receive the message and print it to stdout:

2023-02-24 17:06:32 +0000 [info]: starting fluentd-1.15.3 pid=1 ruby="3.2.0"
2023-02-24 17:06:32 +0000 [info]: spawn command to main:  cmdline=["/usr/bin/ruby", "-Eascii-8bit:ascii-8bit", "/usr/bin/fluentd", "--under-supervisor"]
2023-02-24 17:06:32 +0000 [info]: init supervisor logger path=nil rotate_age=nil rotate_size=nil
2023-02-24 17:06:32 +0000 [info]: #0 init worker0 logger path=nil rotate_age=nil rotate_size=nil
2023-02-24 17:06:32 +0000 [info]: adding match pattern="*.*" type="stdout"
2023-02-24 17:06:32 +0000 [info]: adding source type="forward"
2023-02-24 17:06:32 +0000 [warn]: #0 define <match fluent.**> to capture fluentd logs in top level is deprecated. Use <label @FLUENT_LOG> instead
2023-02-24 17:06:32 +0000 [info]: #0 starting fluentd worker pid=11 ppid=1 worker=0
2023-02-24 17:06:32 +0000 [info]: #0 listening port port=24224 bind=""
2023-02-24 17:06:32 +0000 [info]: #0 fluentd worker is now running worker=0
2023-02-24 17:06:32.824499403 +0000 {"pid":11,"ppid":1,"worker":0,"message":"starting fluentd worker pid=11 ppid=1 worker=0"}
2023-02-24 17:06:32.824689854 +0000 {"port":24224,"bind":"","message":"listening port port=24224 bind=\"\""}
2023-02-24 17:06:32.825323737 +0000 {"worker":0,"message":"fluentd worker is now running worker=0"}
2023-02-24 17:06:54.000000000 +0000 docker.eb2613ef91b4: {"container_id":"eb2613ef91b4fa0989b7af9f3b1310bc4de6c13aae5ee42901d553e81b575045","container_name":"/focused_fermat","source":"stdout","log":"Hello Fluentd!"}

Using the -dev variant

The -dev variant contains a shell and tools like apk to allow users to easily debug and modify the image. The -dev variant uses the same entrypoint as the regular image so if you want to get a shell make sure to override the entrypoint like so.

docker run --rm --entrypoint 'sh'

Last updated: 2024-02-16 00:30