How-To: Run Redis in Docker on Windows

Contents:

Summary
Walkthough
Why Docker

Summary

This is a very condensed summary.

1. Run Redis instances

From Docker command line:

$ docker run -d -p 6379:6379 redis:3.0.1
$ docker run -d -p 6380:6379 redis:2.8.20
$ docker run -d -p 6381:6379 redis:2.8.12

2. Connect to them using redis-cli

Find out Docker VM IP:

	$ boot2docker.exe ip
	192.168.59.103

Connect using redis-cli:

	# Redis 3.0.1
	redis-cli -h 192.168.59.103 -p 6379
	
	# Redis 2.8.20
	redis-cli -h 192.168.59.103 -p 6380
	
	# Redis 2.8.12
	redis-cli -h 192.168.59.103 -p 6381

Walkthrough

A more detailed version.

Assuming Docker is already installed. If not, here is How to install Docker on Windows post.

Here is what I want to do:

Run 3 instances of Redis on Linux:
- v 2.8.12
- v 2.8.20
- v 3.0.1
Use redis-cli on Windows to connect to them

Here are the steps:

1. Run Boot2Docker

This will get us the Docker command prompt.

2. Run Redis images

From the Docker command prompt, run these

$ docker run -d -p 6379:6379 redis:3.0.1
$ docker run -d -p 6380:6379 redis:2.8.20
$ docker run -d -p 6381:6379 redis:2.8.12

The -p switch is very important. It has format [external IP : internal IP] and allows us to get to things inside Docker container.

For example, "-p 6381:6379" means that Docker VM will listen on port 6381 and forward all traffic on that port to whatever is listening on port 6379 in the container.

In case of our Redis instances, all three of them listen on port 6379 inside the container. But to get to them from outside, we need to tell Docker to forward exteranl traffic to them and we do this by providing this mapping.

If you don’t specify this mapping, you won’t be able to get to the Redis instance from outside (at least I couldn’t).

The -d switch is not important. It just means “run in background”.

3. Confirm the images are running

From the Docker command prompt, run this:

$ docker ps -a

If everything is well, you should see output like this:

CONTAINER ID        IMAGE               COMMAND                CREATED             STATUS                           PORTS                    NAMES
3dcb8275035f        redis:2.8.12        "/entrypoint.sh redi   7 minutes ago       Up 7 minutes                     0.0.0.0:6381->6379/tcp   admiring_pike
bdf186ade5f3        redis:2.8.20        "/entrypoint.sh redi   7 minutes ago       Up 7 minutes                     0.0.0.0:6380->6379/tcp   serene_brattain
bb7b03c03c21        redis:3.0.1         "/entrypoint.sh redi   8 minutes ago       Up 8 minutes                     0.0.0.0:6379->6379/tcp   nostalgic_kirch

Note the columns:

IMAGE. This has the name of the image we asked Docker to run earlier, together with version.
PORTS. This is the effect of the -p switch. It shows the external->internal mapping of IP ports.
STATUS. Tells whether the image is actually running.
NAMES. These are auto-generate by Docker. You use these to control the running images with other Docker commands.

4. Get Redis client for Windows

Two options:

Using nuget from command prompt (assuming you have nuget.exe command line tool). E.g.:

  c:>cd \temp
	
  C:\Temp>nuget install Redis-64
  Installing 'Redis-64 2.8.19'.
  Successfully installed 'Redis-64 2.8.19'
	
  C:\Temp>cd Redis-64.2.8.19

From MSOpenTech github repository here: https://github.com/MSOpenTech/redis/releases.

Get the zip file or MSI.

5. Connect to Redis running in Docker

What you need to know:

The IP address of the Docker VM (see above).
The port of the Redis instance you want to connect to.

These two steps in turn.

5.1 Find out the IP address of the Docker VM

This is the IP address to which we will need to point our redis-cli client.

Two options:

from Boot2Docker command prompt run boot2docker.exe ip. This will show the IP address:
```
  $ boot2docker.exe ip
  192.168.59.103
```

Look for DOCKER-HOST string when you start Boot2Docker:

  ...
  starting...
  Waiting for VM and Docker daemon to start...
  .o
  Started.
  ...
	
  To connect the Docker client to the Docker daemon, please set:
      export DOCKER_HOST=tcp://192.168.59.103:2376

5.2 Find out the ports to use

Two options:

Remeber the -p switch we used to run Redis instance.
```
  $ docker run -d -p 6381:6379 redis:2.8.12
```
In this case we will need to use port 6381.

Use "docker ps -a" command from Docker command line and look at PORTS column.

In our case, we will need the first port.

  IMAGE               PORTS                  
  redis:2.8.12        0.0.0.0:6381->6379/tcp 
  redis:2.8.20        0.0.0.0:6380->6379/tcp 
  redis:3.0.1         0.0.0.0:6379->6379/tcp

5.3 Finally – connect

With all this information, to connect to Redis instances:

# Version 3.0.1
redis-cli -h 192.168.59.103 -p 6379

# Version 2.8.20
redis-cli -h 192.168.59.103 -p 6380

# Version 2.8.12
redis-cli -h 192.168.59.103 -p 6381

That’s it :)

Why Docker?

If all of the above sounded complicated, consider these scenarios:

I’m on Windows and want to run Redis 3.0.
I’m on Windows and want to run a Linux version of Redis.
I want to run multiple instances of different versions of Redis on Linux.

Life without Docker

Without docker those scenarios would require quite a bit more work: - building a separate Linux VM, - understanding how it works, - then getting that particular version of Redis onto it (may be not so trivial depending on the distribution of Linux).

It will require time plus knowledge of a particular Linux distribution and how to get Redis binaries onto it.

Now consider Docker.

Life with Docker

Run multiple versions of Redis (or anything really) at the same time;
No knowledge of Linux required;
No need to figure out where to get distributions and Redis from;
Takes only a few seconds to get up and running.

There are still a few things to learn but it’s still much easier than doing it yourself without Docker.