More fun with Docker: creating a Drupal site

Cloud computing is enabling some really cool stuff. I just provisioned my Mac laptop for running MySQL and Drupal, and these are provisioned in a way that when I am satisfied with my work (locally), I can fix the relevant containers into uploadable images to be used on Amazon EC2.

Here's how it happens:

Over the weekend, I decided that I wanted to setup a new website for the Boy Scout troop that I serve. I decided to give Drupal a look, and after some searching, discovered that there are already canned images at Dockerhub for just my use case. The image I decided to use is centurylink/drupal:latest. CenturyLink Research also has created a centurylink/mysql image that combines nicely to create a runnable web site on my Mac in very few steps:

[Prerequisite, I already have boot2docker and docker installed on my Mac via homebrew; also, I am registered with Dockerhub and logged in using boot2docker login].

Just to prove that I've managed to truly capture all prerequisites for this blog post,

tk-mbp:~ tommy$ boot2docker destroy; boot2docker init; boot2docker up

That initializes a VirtualBox VM and eventually asks me a few times for the password:

Waiting for VM and Docker daemon to start...
.................................docker@localhost's password: 
.docker@localhost's password: 
docker@localhost's password: 
Started.
docker@localhost's password: 
To connect the Docker client to the Docker daemon, please set:
    export DOCKER_HOST=tcp://192.168.59.103:2375

(docker's password is 'tcuser'). (Also, note for later the Docker VM's IP address).

Next, I obey the "To connect..." instructions:

tk-mbp:~ tommy$ export DOCKER_HOST=tcp://192.168.59.103:2375

And pull the first of 2 needed images:

tk-mbp:~ tommy$ docker pull centurylink/mysql:latest

Pulling repository centurylink/mysql

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Then pulling the second required image:

tk-mbp:~ tommy$ docker pull centurylink/drupal:latest

Pulling repository centurylink/drupal

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The next step is to fire up the mysql image in a container and then link that container when firing up the drupal image:

tk-mbp:~ tommy$ docker run -d -p 3306:3306 --name MYSQL -e MYSQL_ROOT_PASSWORD=pass@word01 -e MYSQL_DATABASE=troop1691 -e MYSQL_USER=troop1691 -e MYSQL_PASSWORD=troop1691 centurylink/mysql:latest

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That one's probably worth picking apart. I'm telling docker to run an image in "detached" (background) mode; mapping the host (not the real Mac OS X host, but the boot2docker VirtualBox host) port 3306 to the container port 3306, giving the container the name "MYSQL", and setting some environment variables.

Next, I tell Docker to fire up the drupal image in another container (on the same VirtualBox VM) and link to the MYSQL container as "DB":

tk-mbp:~ tommy$ docker run -d --name DRUPAL -P --link MYSQL:DB centurylink/drupal:latest

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At this point, all that's left is to connect my web browser to the running Drupal and get to work on the real problem that I wanted to work on. To facilitate that, I just have to figure out what port is listening on the VirtualBox VM:

tk-mbp:~ tommy$ docker ps

CONTAINER ID        IMAGE                       COMMAND                CREATED             STATUS              PORTS                    NAMES

a6e2eccb3d45        centurylink/drupal:latest   "/bin/sh -c 'exec su   2 minutes ago       Up 2 minutes        0.0.0.0:49153->80/tcp    DRUPAL              

7d78f4ec98a0        centurylink/mysql:latest    "/usr/local/bin/run"   8 minutes ago       Up 8 minutes        0.0.0.0:3306->3306/tcp   DRUPAL/DB,MYSQL     

This shows that the "DRUPAL" container is listening on host (VM) port 49153. Putting the VM's IP address into /etc/hosts with the name 'drupal', and firing up my web browser, I'm ready to complete Drupal setup and begin work on my site, which was the real task I wanted to be working on anyway.

(there's actually one more minor thing, enabled by the container linking, that ends up being useful: I told Drupal to use the hostname "db" since that was the link name given for the MYSQL container at the time I instantiated the DRUPAL container: