---
description: Installing and running a redis service
keywords: docker, example, package installation, networking,  redis
title: Dockerize a Redis service
---

Very simple, no frills, Redis service attached to a web application
using a link.

## Create a Docker container for Redis

Firstly, we create a `Dockerfile` for our new Redis
image.

```dockerfile
FROM        ubuntu:14.04
RUN         apt-get update && apt-get install -y redis-server
EXPOSE      6379
ENTRYPOINT  ["/usr/bin/redis-server"]
```

Next we build an image from our `Dockerfile`.
Replace `<your username>` with your own user name.

```bash
$ docker build -t <your username>/redis .
```

## Run the service

Use the image we've just created and name your container `redis`.

Running the service with `-d` runs the container in detached mode, leaving
the container running in the background.

Importantly, we're not exposing any ports on our container. Instead
we're going to use a container link to provide access to our Redis
database.

```bash
$ docker run --name redis -d <your username>/redis
```

## Create your web application container

Next we can create a container for our application. We're going to use
the `-link` flag to create a link to the `redis` container we've just
created with an alias of `db`. This will create a secure tunnel to the
`redis` container and expose the Redis instance running inside that
container to only this container.

```bash
$ docker run --link redis:db -i -t ubuntu:14.04 /bin/bash
```

Once inside our freshly created container we need to install Redis to
get the `redis-cli` binary to test our connection.

```bash
$ sudo apt-get update
$ sudo apt-get install redis-server
$ sudo service redis-server stop
```

As we've used the `--link redis:db` option, Docker
has created some environment variables in our web application container.

```bash
$ env | grep DB_

# Should return something similar to this with your values
DB_NAME=/violet_wolf/db
DB_PORT_6379_TCP_PORT=6379
DB_PORT=tcp://172.17.0.33:6379
DB_PORT_6379_TCP=tcp://172.17.0.33:6379
DB_PORT_6379_TCP_ADDR=172.17.0.33
DB_PORT_6379_TCP_PROTO=tcp
```

We can see that we've got a small list of environment variables prefixed
with `DB`. The `DB` comes from the link alias specified when we launched
the container. Let's use the `DB_PORT_6379_TCP_ADDR` variable to connect to
our Redis container.

```bash
$ redis-cli -h $DB_PORT_6379_TCP_ADDR

$ redis 172.17.0.33:6379>
$ redis 172.17.0.33:6379> set docker awesome

OK

$ redis 172.17.0.33:6379> get docker

"awesome"

$ redis 172.17.0.33:6379> exit
```
We could easily use this or other environment variables in our web
application to make a connection to our `redis`
container.