Finally I got a chance to play with Docker and was pretty satisfied with the experience. There are some rough edges, but it didn’t lessen my excitement. Docker is stable for a few months, currently the latest version is 1.2.
I will try to use Docker to run different versions of MySQL and PostgreSQL for testing purposes at Datazenit. Docker was pretty easy to setup both on my development MacBook and on a Linux server. Docker offers a nice, official package for OSX that installs all dependencies, including, VirtualBox. An interactive tutorial can be found on Docker website, and it covers all core aspects of Docker.
I found out that there are pre-made repositories for MySQL and PostgreSQL images. I started with MySQL and got a working container within 10 minutes. Most of the time was spent to download the image, so I can say that the process was really simple. Sadly only the latest version worked flawlessly. I haven’t yet looked carefully enough, but each of the older versions had some random errors. Maybe it could be related to the fact that I run all containers on a single host, but that would be strange and it would also defeat the whole point of Docker containers.
Another unexpected thing was that you need to configure a separate volume container if you want a persistant and stable storage for your containers. Link to official docs regarding this – Managing Data in Containers. However one sentence from docs was confusing: “Volumes persist until no containers use them” So is the special volume container really persistent or not? If I reboot my host will the volume container lose all its data? But this is probably just a confusement caused by not RTFM. Will learn more and report back.