/fluentd-docker-image

Docker image for Fluentd

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Fluentd Docker Image

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What is Fluentd?

Fluentd is an open source data collector, which lets you unify the data collection and consumption for a better use and understanding of data.

www.fluentd.org

Fluentd Logo

Supported tags and respective Dockerfile links

Current images

These tags have image version postfix. This updates many places so we need feedback for improve/fix the images.

Older images (before official image)

We recommend to use debian version for production because it uses jemalloc to mitigate memory fragmentation issue.

v1.x is for fluentd v1.x releases. This is current stable version. v0.12 is for fluentd v0.12.x releases. This is old stable.

You can use older versions via tag. See tag page on Docker Hub.

Using Kubernetes?

Check fluentd-kubernetes-daemonset images.

The detail of image tag

This image is based on the popular Alpine Linux project, available in the alpine official image, and Debian images.

For current images

edge

Latest version of edge Fluentd branch (currently v1.3-1).

vX.Y-A

Latest version of vX.Y Fluentd branch.

A will be incremented when image has major changes.

vX.Y.Z-A.B

Concrete vX.Y.Z version of Fluentd.

A will be incremented when image has major changes. B will be incremented when image has small changes, e.g. library update or bug fixes.

onbuild included tag

This image makes building derivative images easier. See "How to build your own image" section for more details.

debian included tag

The image based on Debian Linux image. You may use this image when you require plugins which cannot be installed on Alpine (like fluent-plugin-systemd).

armhf included tag

The armhf images use ARM base images for use on devices such as Raspberry Pis.

Furthermore, the base images enable support for cross-platform builds using the cross-build tools from resin.io.

In order to build these images natively on ARM devices, the CROSS_BUILD_START and CROSS_BUILD_END Docker build arguments must be set to the shell no-op (:), for example:

docker build --build-arg CROSS_BUILD_START=":" --build-arg CROSS_BUILD_END=":" -t fluent/fluentd:v1.3.2-onbuild v1.3/armhf/alpine-onbuild

(assuming the command is run from the root of this repository).

For older images

stable, latest

Latest version of stable Fluentd branch (currently v1.3).

vX.Y

Latest version of vX.Y Fluentd branch.

vX.Y.Z

Concrete vX.Y.Z version of Fluentd.

onbuild included tag, debian included tag, armhf included tag

Same as current images.

How to use this image

To create endpoint that collects logs on your host just run:

docker run -d -p 24224:24224 -p 24224:24224/udp -v /data:/fluentd/log fluent/fluentd:v1.3-debian-1

Default configurations are to:

  • listen port 24224 for Fluentd forward protocol
  • store logs with tag docker.** into /fluentd/log/docker.*.log (and symlink docker.log)
  • store all other logs into /fluentd/log/data.*.log (and symlink data.log)

Providing your own configuration file and additional options

fluentd arguments can be appended to the docker run line

For example, to provide a bespoke config and make fluentd verbose, then:

docker run -ti --rm -v /path/to/dir:/fluentd/etc fluentd -c /fluentd/etc/<conf> -v

The first -v tells Docker to share '/path/to/dir' as a volume and mount it at /fluentd/etc The -c after the container name (fluentd) tells fluentd where to find the config file The second -v is passed to fluentd to tell it to be verbose

Change running user

Use -u option with docker run.

docker run -p 24224:24224 -u foo -v ...

How to build your own image

You can build a customized image based on Fluentd's onbuild image. Customized image can include plugins and fluent.conf file.

1. Create a working directory

We will use this directory to build a Docker image. Type following commands on a terminal to prepare a minimal project first:

# Create project directory.
mkdir custom-fluentd
cd custom-fluentd

# Download default fluent.conf. This file will be copied to the new image.
# VERSION is v1.3 or v0.12 like fluentd version and OS is alpine or debian.
# Full example is https://raw.githubusercontent.com/fluent/fluentd-docker-image/master/v0.12/debian-onbuild/fluent.conf
curl https://raw.githubusercontent.com/fluent/fluentd-docker-image/master/VERSION/OS-onbuild/fluent.conf > fluent.conf

# Create plugins directory. plugins scripts put here will be copied to the new image.
mkdir plugins

curl https://raw.githubusercontent.com/fluent/fluentd-docker-image/master/Dockerfile.sample > Dockerfile

2. Customize fluent.conf

Documentation of fluent.conf is available at docs.fluentd.org.

3. Customize Dockerfile to install plugins (optional)

You can install Fluentd plugins using Dockerfile. Sample Dockerfile installs fluent-plugin-elasticsearch. To add plugins, edit Dockerfile as following:

3.1 For current images

Alpine version

FROM fluent/fluentd:v1.3-onbuild-1

# Use root account to use apk
USER root

# below RUN includes plugin as examples elasticsearch is not required
# you may customize including plugins as you wish
RUN apk add --no-cache --update --virtual .build-deps \
        sudo build-base ruby-dev \
 && sudo gem install \
        fluent-plugin-elasticsearch \
 && sudo gem sources --clear-all \
 && apk del .build-deps \
 && rm -rf /home/fluent/.gem/ruby/2.5.0/cache/*.gem

USER fluent

Debian version

FROM fluent/fluentd:v1.3-debian-onbuild-1

# Use root account to use apt
USER root

# below RUN includes plugin as examples elasticsearch is not required
# you may customize including plugins as you wish
RUN buildDeps="sudo make gcc g++ libc-dev ruby-dev" \
 && apt-get update \
 && apt-get install -y --no-install-recommends $buildDeps \
 && sudo gem install \
        fluent-plugin-elasticsearch \
 && sudo gem sources --clear-all \
 && SUDO_FORCE_REMOVE=yes \
    apt-get purge -y --auto-remove \
                  -o APT::AutoRemove::RecommendsImportant=false \
                  $buildDeps \
 && rm -rf /var/lib/apt/lists/* \
           /home/fluent/.gem/ruby/2.3.0/cache/*.gem

USER fluent

Note

These example run apk add/apt-get install to be able to install Fluentd plugins which require native extensions (they are removed immediately after plugin installation). If you're sure that plugins don't include native extensions, you can omit it to make image build faster.

3.2 For older images

Alpine version

FROM fluent/fluentd:v1.3.2-onbuild

# below RUN includes plugin as examples elasticsearch is not required
# you may customize including plugins as you wish

RUN apk add --no-cache --update --virtual .build-deps \
        sudo build-base ruby-dev \
 && sudo gem install \
        fluent-plugin-elasticsearch \
 && sudo gem sources --clear-all \
 && apk del .build-deps \
 && rm -rf /home/fluent/.gem/ruby/2.5.0/cache/*.gem

Debian version

FROM fluent/fluentd:v1.3.2-debian-onbuild

# below RUN includes plugin as examples elasticsearch is not required
# you may customize including plugins as you wish

RUN buildDeps="sudo make gcc g++ libc-dev ruby-dev" \
 && apt-get update \
 && apt-get install -y --no-install-recommends $buildDeps \
 && sudo gem install \
        fluent-plugin-elasticsearch \
 && sudo gem sources --clear-all \
 && SUDO_FORCE_REMOVE=yes \
    apt-get purge -y --auto-remove \
                  -o APT::AutoRemove::RecommendsImportant=false \
                  $buildDeps \
 && rm -rf /var/lib/apt/lists/* \
           /home/fluent/.gem/ruby/2.3.0/cache/*.gem

4. Build image

Use docker build command to build the image. This example names the image as custom-fluentd:latest:

docker build -t custom-fluentd:latest ./

5. Test it

Once the image is built, it's ready to run. Following commands run Fluentd sharing ./log directory with the host machine:

mkdir -p log
docker run -it --rm --name custom-docker-fluent-logger -v $(pwd)/log:/fluentd/log custom-fluentd:latest

Open another terminal and type following command to inspect IP address. Fluentd is running on this IP address:

docker inspect -f '{{.NetworkSettings.IPAddress}}' custom-docker-fluent-logger

Let's try to use another docker container to send its logs to Fluentd.

docker run --log-driver=fluentd --log-opt tag="docker.{{.ID}}" --log-opt fluentd-address=FLUENTD.ADD.RE.SS:24224 python:alpine echo Hello
# and force flush buffered logs
docker kill -s USR1 custom-docker-fluent-logger

(replace FLUENTD.ADD.RE.SS with actual IP address you inspected at the previous step)

You will see some logs sent to Fluentd.

References

Docker Logging | fluentd.org

Fluentd logging driver - Docker Docs

Issues

We can't notice comments in the DockerHub so don't use them for reporting issue or asking question.

If you have any problems with or questions about this image, please contact us through a GitHub issue.