Run Redis with Docker

Why run Redis with Docker?

To use Redis you need Redis running somewhere. The easiest way to run Redis on your machine is Docker: you install nothing system-wide, and you can throw the whole thing away cleanly when you are done.

This lesson assumes you have Docker installed and running. If you can run docker --version and see a number, you are ready.

Start Redis with one command

Open a terminal and run:

docker run -d --name redis -p 6379:6379 redis:7

That is the whole thing. Redis is now running. Let's break down each part:

• docker run starts a new container.
• -d runs it detached, in the background, so your terminal stays free.
• --name redis gives the container the name redis so you can refer to it later.
• -p 6379:6379 maps port 6379 inside the container to port 6379 on your machine. 6379 is the default Redis port.
• redis:7 is the image to run: official Redis, version 7.

Check that it is running:

docker ps

You should see a container named redis in the list.

Run Redis with docker-compose instead

If you prefer a file you can commit to your project, use a minimal docker-compose.yml:

services:
  redis:
    image: redis:7
    ports:
      - "6379:6379"

Then, from the folder with that file, start it:

docker compose up -d

This does the same job as the docker run command above. The advantage is that the setup lives in a file, so your teammates get the exact same Redis with one command.

Get a shell into Redis

Redis ships with a built-in command-line tool called redis-cli. It lets you type commands to Redis directly. Because Redis is running inside the container, we run the tool inside the container too:

docker exec -it redis redis-cli

Breaking it down:

• docker exec runs a command inside a running container.
• -it makes it interactive so you can type and see responses.
• redis is the container name from earlier.
• redis-cli is the tool we want to run.

Your prompt changes to something like this:

127.0.0.1:6379>

That prompt means you are talking to Redis. We will use it constantly in the next lesson.

Verify it works with PING

The simplest way to confirm Redis is alive is the PING command. At the redis-cli prompt, type:

PING

Redis replies:

PONG

PONG means Redis heard you and is healthy. That is the "hello world" of Redis.

To leave the prompt, type exit or press Ctrl+D. The container keeps running in the background.

Common mistake

If docker run fails with a message about port 6379 being already in use, something else (often a Redis you installed earlier, or another container) is using that port. Stop the other one, or map a different local port like -p 6380:6379.

A second snag catches people the day after: you docker stop redis, come back later, run the exact same docker run command, and Docker complains the name redis is already in use. Stopping a container does not delete it, so the name is still taken. Either start the existing one again with docker start redis, or remove it first with docker rm redis and then run fresh.

FAQ

Do I have to install Redis to follow this course?

No. Docker runs it for you. That is why we start here instead of installing Redis directly.

How do I stop and remove the container?

Run docker stop redis to stop it and docker rm redis to remove it. With compose, use docker compose down.

Why version 7?

redis:7 pins a stable, widely used major version so everyone in this course runs the same Redis and sees the same behavior.

The container is running but PING does nothing. What now?

Make sure you are actually at the redis-cli prompt (it shows 127.0.0.1:6379>). PING is a Redis command, not a shell command, so it only works inside redis-cli.