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. https://www.fluentd.org

TL;DR

$ docker run --name fluentd bitnami/fluentd:latest

You can find the available configuration options in the Environment Variables section.

Why use Bitnami Images?

• Bitnami closely tracks upstream source changes and promptly publishes new versions of this image using our automated systems.
• With Bitnami images the latest bug fixes and features are available as soon as possible.
• Bitnami containers, virtual machines and cloud images use the same components and configuration approach - making it easy to switch between formats based on your project needs.
• All our images are based on minideb a minimalist Debian based container image which gives you a small base container image and the familiarity of a leading Linux distribution.
• All Bitnami images available in Docker Hub are signed with Docker Content Trust (DCT). You can use DOCKER_CONTENT_TRUST=1 to verify the integrity of the images.
• Bitnami container images are released daily with the latest distribution packages available.

This CVE scan report contains a security report with all open CVEs. To get the list of actionable security issues, find the "latest" tag, click the vulnerability report link under the corresponding "Security scan" field and then select the "Only show fixable" filter on the next page.

Why use a non-root container?

Non-root container images add an extra layer of security and are generally recommended for production environments. However, because they run as a non-root user, privileged tasks are typically off-limits. Learn more about non-root containers in our docs.

Supported tags and respective Dockerfile links

Learn more about the Bitnami tagging policy and the difference between rolling tags and immutable tags in our documentation page.

• 1, 1-debian-10, 1.12.0, 1.12.0-debian-10-r11, latest (1/debian-10/Dockerfile)

Subscribe to project updates by watching the bitnami/fluentd GitHub repo.

Get this image

The recommended way to get the Bitnami Fluentd Docker Image is to pull the prebuilt image from the Docker Hub Registry.

$ docker pull bitnami/fluentd:latest

To use a specific version, you can pull a versioned tag. You can view the list of available versions in the Docker Hub Registry.

$ docker pull bitnami/fluentd:[TAG]

If you wish, you can also build the image yourself.

$ docker build -t bitnami/fluentd:latest 'https://github.com/bitnami/bitnami-docker-fluentd.git#master:1/debian-10'

Connecting to other containers

Using Docker container networking, a different server running inside a container can easily be accessed by your application containers and vice-versa.

Containers attached to the same network can communicate with each other using the container name as the hostname.

Using the Command Line

Step 1: Create a network

$ docker network create fluentd-network --driver bridge

Step 2: Launch the Blacbox_exporter container within your network

Use the --network <NETWORK> argument to the docker run command to attach the container to the fluentd-network network.

$ docker run --name fluentd-node1 --network fluentd-network bitnami/fluentd:latest

Step 3: Run another containers

We can launch another containers using the same flag (--network NETWORK) in the docker run command. If you also set a name to your container, you will be able to use it as hostname in your network.

Configuration

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

$ docker run -d -p 24224:24224 -p 24224:24224/udp -v /data:/opt/bitnami/fluentd/log fluentd

Default configurations are:

• configuration file at /opt/bitnami/fluentd/conf/fluentd.conf
• listen port 24224 for Fluentd forward protocol
• store logs with tag docker.** into /opt/bitnami/fluentd/log/docker.*.log
• store all other logs into /opt/bitnami/fluentd/log/data.*.log

You can overwrite the default configuration file by mounting your own configuration file on the directory /opt/bitnami/fluentd/conf:

$ docker run --name fluentd -v /path/to/fluentd.conf:/opt/bitnami/fluentd/conf/fluentd.conf bitnami/fluentd:latest

You can also do this by changing the docker-compose.yml file present in this repository:

fluentd:
  ...
  volumes:
    - /path/to/fluentd.conf:/opt/bitnami/fluentd/conf/fluentd.conf
  ...

You can also extend the default configuration by importing your custom configuration with the "@include" directive. It is a simple as creating a directory with you custom config files and mount it on the directory /opt/bitnami/fluentd/conf/conf.d:

$ docker run --name fluentd -v /path/to/custom-conf-directory:/opt/bitnami/fluentd/conf/conf.d bitnami/fluentd:latest

You can also do this by changing the docker-compose.yml file present in this repository:

fluentd:
  ...
  volumes:
    - /path/to/custom-conf-directory:/opt/bitnami/fluentd/conf/conf.d
  ...

Find more information about this feature, consult official documentation

Environment Variables

Environment variable below are configurable to control how to execute fluentd process:

• FLUENTD_CONF: This variable allows you to specify configuration file name that will be used in -c Fluentd command line option. If you want to use your own configuration file (without any optional plugins), you can do it with this environment variable and Docker volumes (-v option of docker run).
• FLUENTD_OPT: Use this variable to specify other Fluentd command line options, like -v or -q.
• FLUENTD_DAEMON_USER: The user that will run the fluentd process when the container is run as root.
• FLUENTD_DAEMON_GROUP: The group of the user that will run the fluentd process when the container is run as root.

Logging

The Bitnami fluentd Docker image sends the container logs to the stdout. To view the logs:

$ docker logs fluentd

You can configure the containers logging driver using the --log-driver option if you wish to consume the container logs differently. In the default configuration docker uses the json-file driver.

Understand the structure of this image

The Bitnami Fluentd Open Source Docker image is built using a Dockerfile with the structure below:

FROM bitnami/minideb:buster
...
COPY prebuildfs /
# Install required system packages and dependencies
RUN install_packages xxx yyy zzz
RUN . /opt/bitnami/scripts/libcomponent.sh && component_unpack "ruby" "a.b.c-0"
RUN . /opt/bitnami/scripts/libcomponent.sh && component_unpack "fluentd" "d.e.f-0"
...
COPY rootfs /
RUN /opt/bitnami/scripts/fluentd/postunpack.sh
...
ENV BITNAMI_APP_NAME="fluentd" ...
EXPOSE 24224 5140
WORKDIR /opt/bitnami/fluentd
USER 1001
...
ENTRYPOINT [ "/opt/bitnami/scripts/fluentd/entrypoint.sh" ]
CMD [ "/opt/bitnami/scripts/fluentd/run.sh" ]

The Dockerfile has several sections related to:

• Components installation
• Components static configuration
• Environment variables
• Ports to be exposed
• Working directory and user
  • Note that once the user is set to 1001, unprivileged commands cannot be executed any longer.
• Entrypoint and command
  • Take into account that these actions are not executed until the container is started.

Customize this image

The Bitnami Fluentd Open Source Docker image is designed to be extended so it can be used as the base image for your custom Fluentd containers.

Note: Read the previous section to understand the Dockerfile structure before extending this image.

Extend this image

Before extending this image, please note there are certain configuration settings you can modify using the original image:

• Settings that can be adapted using environment variables. For instance, you can modify the Fluentd command-line options setting the environment variable FLUENTD_OPT.
• Replacing the default configuration file by mounting your own configuration file .

If your desired customizations cannot be covered using the methods mentioned above, extend the image. To do so, create your own image using a Dockerfile with the format below:

FROM bitnami/fluentd
## Put your customizations below
...

Here is an example of extending the image installing custom Fluentd plugins:

FROM bitnami/fluentd
LABEL maintainer "Bitnami <containers@bitnami.com>"

## Install custom Fluentd plugins
RUN fluent-gem install 'fluent-plugin-docker_metadata_filter'

Maintenance

Upgrade this image

Bitnami provides up-to-date versions of fluentd, including security patches, soon after they are made upstream. We recommend that you follow these steps to upgrade your container.

Step 1: Get the updated image

$ docker pull bitnami/fluentd:latest

Step 2: Stop and backup the currently running container

Stop the currently running container using the command

$ docker stop fluentd

Next, take a snapshot of the persistent volume /path/to/fluentd-persistence using:

$ rsync -a /path/to/fluentd-persistence /path/to/fluentd-persistence.bkp.$(date +%Y%m%d-%H.%M.%S)

You can use this snapshot to restore the database state should the upgrade fail.

Step 3: Remove the currently running container

$ docker rm -v fluentd

Step 4: Run the new image

Re-create your container from the new image, restoring your backup if necessary.

$ docker run --name fluentd bitnami/fluentd:latest

Contributing

We'd love for you to contribute to this container. You can request new features by creating an issue, or submit a pull request with your contribution.

Issues

If you encountered a problem running this container, you can file an issue. For us to provide better support, be sure to include the following information in your issue:

• Host OS and version
• Docker version (docker version)
• Output of docker info
• Version of this container
• The command you used to run the container, and any relevant output you saw (masking any sensitive information)

License

Copyright (c) 2021 Bitnami

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.