What is Redis?

Redis is an advanced key-value cache and store. It is often referred to as a data structure server since keys can contain strings, hashes, lists, sets, sorted sets, bitmaps and hyperloglogs.

redis.io

TL;DR;

$ docker run --name redis -e ALLOW_EMPTY_PASSWORD=yes bitnami/redis:latest

Docker Compose

$ curl -sSL https://raw.githubusercontent.com/bitnami/bitnami-docker-redis/master/docker-compose.yml > docker-compose.yml
$ docker-compose up -d

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.
• Bitnami images are built on CircleCI and automatically pushed to the Docker Hub.
• 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.

Get this image

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

$ docker pull bitnami/redis: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/redis:[TAG]

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

$ docker build -t bitnami/redis:latest https://github.com/bitnami/bitnami-docker-redis.git

Persisting your database

If you remove the container all your data and configurations will be lost, and the next time you run the image the database will be reinitialized. To avoid this loss of data, you should mount a volume that will persist even after the container is removed.

For persistence you should mount a directory at the /bitnami path. If the mounted directory is empty, it will be initialized on the first run.

$ docker run \
    -e ALLOW_EMPTY_PASSWORD=yes \
    -v /path/to/redis-persistence:/bitnami \
    bitnami/redis:latest

or using Docker Compose:

version: '2'

services:
  redis:
    image: 'bitnami/redis:latest'
    environment:
      - ALLOW_EMPTY_PASSWORD=yes
    ports:
      - '6379:6379'
    volumes:
      - /path/to/redis-persistence:/bitnami

Connecting to other containers

Using Docker container networking, a Redis server running inside a container can easily be accessed by your application containers.

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

Using the Command Line

In this example, we will create a Redis client instance that will connect to the server instance that is running on the same docker network as the client.

Step 1: Create a network

$ docker network create app-tier --driver bridge

Step 2: Launch the Redis server instance

Use the --network app-tier argument to the docker run command to attach the Redis container to the app-tier network.

$ docker run -d --name redis-server \
    -e ALLOW_EMPTY_PASSWORD=yes \
    --network app-tier \
    bitnami/redis:latest

Step 3: Launch your Redis client instance

Finally we create a new container instance to launch the Redis client and connect to the server created in the previous step:

$ docker run -it --rm \
    --network app-tier \
    bitnami/redis:latest redis-cli -h redis-server

Using Docker Compose

When not specified, Docker Compose automatically sets up a new network and attaches all deployed services to that network. However, we will explicitly define a new bridge network named app-tier. In this example we assume that you want to connect to the Redis server from your own custom application image which is identified in the following snippet by the service name myapp.

version: '2'

networks:
  app-tier:
    driver: bridge

services:
  redis:
    image: 'bitnami/redis:latest'
    environment:
      - ALLOW_EMPTY_PASSWORD=yes
    networks:
      - app-tier
  myapp:
    image: 'YOUR_APPLICATION_IMAGE'
    networks:
      - app-tier

IMPORTANT:

1. Please update the YOUR_APPLICATION_IMAGE_ placeholder in the above snippet with your application image
2. In your application container, use the hostname redis to connect to the Redis server

Launch the containers using:

$ docker-compose up -d

Configuration

Passing extra command-line flags to redis-server startup

Passing extra command-line flags to the redis service command is possible through the following env var:

• REDIS_EXTRA_FLAGS: Flags to be appended to the startup command. No defaults

$ docker run --name redis -e ALLOW_EMPTY_PASSWORD=yes -e REDIS_EXTRA_FLAGS='--maxmemory 100mb' bitnami/redis:latest

or using Docker Compose:

version: '2'

services:
  redis:
    image: 'bitnami/redis:latest'
    ports:
      - '6379:6379'
    environment:
      - ALLOW_EMPTY_PASSWORD=yes
      - REDIS_EXTRA_FLAGS=--maxmemory 100mb

Setting the server password on first run

Passing the REDIS_PASSWORD environment variable when running the image for the first time will set the Redis server password to the value of REDIS_PASSWORD.

$ docker run --name redis -e REDIS_PASSWORD=password123 bitnami/redis:latest

or using Docker Compose:

version: '2'

services:
  redis:
    image: 'bitnami/redis:latest'
    ports:
      - '6379:6379'
    environment:
      - REDIS_PASSWORD=password123

Warning The Redis database is always configured with remote access enabled. It's suggested that the REDIS_PASSWORD env variable is always specified to set a password. In case you want to access the database without a password set the environment variable ALLOW_EMPTY_PASSWORD=yes. This is recommended only for development.

Allowing empty passwords

By default the Redis image expects all the available passwords to be set. In order to allow empty passwords, it is necessary to set the ALLOW_EMPTY_PASSWORD=yes env variable. This env variable is only recommended for testing or development purposes. We strongly recommend specifying the REDIS_PASSWORD for any other scenario.

$ docker run --name redis -e ALLOW_EMPTY_PASSWORD=yes bitnami/redis:latest

or using Docker Compose:

version: '2'

services:
  redis:
    image: 'bitnami/redis:latest'
    ports:
      - '6379:6379'
    environment:
      - ALLOW_EMPTY_PASSWORD=yes

Setting up a replication

A replication cluster can easily be setup with the Bitnami Redis Docker Image using the following environment variables:

• REDIS_REPLICATION_MODE: The replication mode. Possible values master/slave. No defaults.
• REDIS_MASTER_HOST: Hostname/IP of replication master (slave parameter). No defaults.
• REDIS_MASTER_PORT_NUMBER: Server port of the replication master (slave parameter). Defaults to 6379.
• REDIS_MASTER_PASSWORD: Password to authenticate with the master (slave parameter). No defaults.

In a replication cluster you can have one master and zero or more slaves. When replication is enabled the master node is in read-write mode, while the slaves are in read-only mode. For best performance its advisable to limit the reads to the slaves.

Step 1: Create the replication master

The first step is to start the Redis master.

$ docker run --name redis-master \
  -e REDIS_REPLICATION_MODE=master \
  -e REDIS_PASSWORD=masterpassword123 \
  bitnami/redis:latest

In the above command the container is configured as the master using the REDIS_REPLICATION_MODE parameter. The REDIS_PASSWORD parameter enables authentication on the Redis master.

Step 2: Create the replication slave

Next we start a Redis slave container.

$ docker run --name redis-slave \
  --link redis-master:master \
  -e REDIS_REPLICATION_MODE=slave \
  -e REDIS_MASTER_HOST=master \
  -e REDIS_MASTER_PORT_NUMBER=6379 \
  -e REDIS_MASTER_PASSWORD=masterpassword123 \
  -e REDIS_PASSWORD=password123 \
  bitnami/redis:latest

In the above command the container is configured as a slave using the REDIS_REPLICATION_MODE parameter. The REDIS_MASTER_HOST, REDIS_MASTER_PORT_NUMBER and REDIS_MASTER_PASSWORD parameters are used connect and authenticate with the Redis master. The REDIS_PASSWORD parameter enables authentication on the Redis slave.

You now have a two node Redis master/slave replication cluster up and running which can be scaled by adding/removing slaves.

If the Redis master goes down you can reconfigure a slave to become a master using:

$ docker exec redis-slave redis-cli -a password123 SLAVEOF NO ONE

Note: The configuration of the other slaves in the cluster needs to be updated so that they are aware of the new master. In our example, this would involve restarting the other slaves with --link redis-slave:master.

With Docker Compose the master/slave replication can be setup using:

version: '2'

services:
  redis-master:
    image: 'bitnami/redis:latest'
    ports:
      - '6379'
    environment:
      - REDIS_REPLICATION_MODE=master
      - REDIS_PASSWORD=my_master_password
    volumes:
      - '/path/to/redis-persistence:/bitnami'

  redis-slave:
    image: 'bitnami/redis:latest'
    ports:
      - '6379'
    depends_on:
      - redis-master
    environment:
      - REDIS_REPLICATION_MODE=slave
      - REDIS_MASTER_HOST=redis-primary
      - REDIS_MASTER_PORT_NUMBER=6379
      - REDIS_MASTER_PASSWORD=my_master_password
      - REDIS_PASSWORD=my_slave_password

Scale the number of slaves using:

$ docker-compose scale redis-primary=1 redis-secondary=3

The above command scales up the number of slaves to 3. You can scale down in the same way.

Note: You should not scale up/down the number of master nodes. Always have only one master node running.

Configuration file

The image looks for configurations in /bitnami/redis/conf/. As mentioned in Persisting your database you can mount a volume at /bitnami and copy/edit the configurations in the /path/to/redis-persistence/redis/conf/. The default configurations will be populated to the conf/ directory if it's empty.

Step 1: Run the Redis image

Run the Redis image, mounting a directory from your host.

$ docker run --name redis \
    -e ALLOW_EMPTY_PASSWORD=yes \
    -v /path/to/redis-persistence:/bitnami \
    bitnami/redis:latest

or using Docker Compose:

version: '2'

services:
  redis:
    image: 'bitnami/redis:latest'
    environment:
      - ALLOW_EMPTY_PASSWORD=yes
    ports:
      - '6379:6379'
    volumes:
      - /path/to/redis-persistence:/bitnami

Step 2: Edit the configuration

Edit the configuration on your host using your favorite editor.

$ vi /path/to/redis-persistence/redis/conf/redis.conf

Step 3: Restart Redis

After changing the configuration, restart your Redis container for changes to take effect.

$ docker restart redis

or using Docker Compose:

$ docker-compose restart redis

Refer to the Redis configuration manual for the complete list of configuration options.

Logging

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

$ docker logs redis

or using Docker Compose:

$ docker-compose logs redis

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.

Maintenance

Upgrade this image

Bitnami provides up-to-date versions of Redis, 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/redis:latest

or if you're using Docker Compose, update the value of the image property to bitnami/redis:latest.

Step 2: Stop and backup the currently running container

Stop the currently running container using the command

$ docker stop redis

or using Docker Compose:

$ docker-compose stop redis

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

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

Step 3: Remove the currently running container

$ docker rm -v redis

or using Docker Compose:

$ docker-compose rm -v redis

Step 4: Run the new image

Re-create your container from the new image.

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

or using Docker Compose:

$ docker-compose start redis

Notable Changes

4.0.1-r1

• The redis container has been migrated to a non-root container approach. Previously the container run as root user and the redis daemon was started as redis user. From now own, both the container and the redis daemon run as user 1001. As a consequence, the configuration files are writable by the user running the redis process.

3.2.0-r0

• All volumes have been merged at /bitnami/redis. Now you only need to mount a single volume at /bitnami/redis for persistence.
• The logs are always sent to the stdout and are no longer collected in the volume.

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 (echo $BITNAMI_IMAGE_VERSION inside the container)
• The command you used to run the container, and any relevant output you saw (masking any sensitive information)

Community

Most real time communication happens in the #containers channel at bitnami-oss.slack.com; you can sign up at slack.oss.bitnami.com.

Discussions are archived at bitnami-oss.slackarchive.io.

License

Copyright (c) 2015-2018 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.