Create a MongoDB Docker Container

This tip will assist you setting up a mongodb container using docker. If you have not yet setup docker, follow my previous tip on getting started with docker.

First, lets take a look at what docker images we have.

dock@saas:~$ sudo docker images
REPOSITORY          TAG                 ID                  CREATED             SIZE
ubuntu              12.04               8dbd9e392a96        4 months ago        131.5 MB (virtual 131.5 MB)
ubuntu              12.10               b750fe79269d        5 months ago        24.65 kB (virtual 180.1 MB)
ubuntu              latest              8dbd9e392a96        4 months ago        131.5 MB (virtual 131.5 MB)
ubuntu              precise             8dbd9e392a96        4 months ago        131.5 MB (virtual 131.5 MB)
ubuntu              quantal             b750fe79269d        5 months ago        24.65 kB (virtual 180.1 MB)

Notice we have the images locally, so if we run the hello world the command runs instantly, without the need to download images again.

Now, lets check if we have and docker containers running:

dock@saas:~$ sudo docker ps
ID                  IMAGE               COMMAND             CREATED             STATUS              PORTS

As expected, we do not have any containers currently running.

Install MongoDB

Start an interactive shell in a container with: sudo docker run -i -t ubuntu /bin/bash

root@f9d75a04ce10:/# apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10

root@f9d75a04ce10:/# echo 'deb http://downloads-distro.mongodb.org/repo/ubuntu-upstart dist 10gen' | tee /etc/apt/sources.list.d/10gen.list

root@f9d75a04ce10:/# apt-get update

# initctl fix
root@a1f0680f8458:/# dpkg-divert --local --rename --add /sbin/initctl

root@a1f0680f8458:/# ln -s /bin/true /sbin/initctl

root@a1f0680f8458:/# apt-get install mongodb-10gen

root@a1f0680f8458:/# mkdir -p /data/db

root@a1f0680f8458:/# mongod
mongod --help for help and startup options
Tue Sep  3 14:10:36.469 [initandlisten] MongoDB starting : pid=125 port=27017 dbpath=/data/db/ 64-bit host=a1f0680f8458

exit

MongoDB starts succesfully in the container. Now we need to commit the container, to save the state and push to the docker index.

sudo docker commit a1f0680f8458 codiez/mongodb

Remember to replace your container id, mine was a1f0680f8458 which you can see at the prompt, and your <username>/<container_name>

dock@saas:~$ sudo docker commit a1f0680f8458 codiez/mongodb

dock@saas:~$ sudo docker login
Username: codiez
Password: 
Email: ismail@codiez.co.za
Login Succeeded
dock@saas:~$ sudo docker push codiez/mongodb
The push refers to a repository [codiez/mongodb] (len: 1)
Processing checksums
Sending image list
Pushing repository codiez/mongodb (1 tags)
Pushing 8dbd9e392a964056420e5d58ca5cc376ef18e2de93b5cc90e868a1bbc8318c1c
Image 8dbd9e392a964056420e5d58ca5cc376ef18e2de93b5cc90e868a1bbc8318c1c already pushed, skipping
Pushing tags for rev [8dbd9e392a964056420e5d58ca5cc376ef18e2de93b5cc90e868a1bbc8318c1c] on {https://registry-1.docker.io/v1/repositories/codiez/mongodb/tags/latest}
Pushing f0ab8043e4e8135379d35410a4847769efb9245d8d4817cb24a2196c434c8506

Once that completes, we can start MongoDB in the container, and map it to a port by running:

sudo docker run -d -p 27017 codiez/mongodb /usr/bin/mongod --smallfiles

This basically runs the container, based on the codiez/mongodb image, with the command /usr/bin/mongod and maps the default mongodb port 27017 to an external port.

Check that the container is running and get the port:

dock@saas:~$ sudo docker ps
ID                  IMAGE                   COMMAND             CREATED             STATUS              PORTS
a02d24fed142        codiez/mongodb:latest   /usr/bin/mongod     5 seconds ago       Up 4 seconds        49157->27017  

$ mongo 192.168.0.21:49157
MongoDB shell version: 2.4.5
connecting to: 192.168.0.21:49157/test
> db
test
> db.posts.insert({title:"Hello MongoDB in Docker"})
> db.posts.find()
{ "_id" : ObjectId("5227058d112c68baaa3b94d9"), "title" : "Hello MongoDB in Docker" }
> 

One final commit to save the command and port mapping. Also notice you do not have to enter in the entire container id when running commands, just the first few characters.

dock@saas:~$ sudo docker ps
ID                  IMAGE                   COMMAND                CREATED             STATUS              PORTS
298a43e2f98e        codiez/mongodb:latest   /usr/bin/mongod --sm   35 seconds ago      Up 34 seconds       49164->27017        
dock@saas:~$ sudo docker commit -run '{"Cmd": ["/usr/bin/mongod", "--smallfiles"], "PortSpecs": [":27017"]}' 298a4 codiez/mongodb

Now that we have an image, we can run docker pull codiez/mongodb to grab the container and run it with docker run -d codiez/mongodb

The next post will discuss automating the creation of a container with a dockerfile.

Originally posted to: http://blog.codiez.co.za/2013/09/setup-a-docker-container-with-mongodb/