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Your First Docker Container

·2 mins

Everyone is talking about Docker these days. Why another virtualization-thing? Why should I bother, am happy with Bento and Vagrant?

I needed answers. The best way to get them is to get a feel for the tool by installing and playing around with it.

This post will bring you up-to-speed in using Docker as fast as possible and provide you some further pointers.

Before your first installation I recommend doing this interactive tutorial.

Installation #

On my Mac, I basically had two options installing Docker, either with boot2docker or in any other virtual machine, because there is no native way to install it on Mac OS X.

At first, I have tried boot2docker but soon ran into limitations (no volumes) and switched to a Vagrant box that I have build as described here.

When the Vagrant box was up I did the following:

{% highlight none %} yum -y install docker service docker start chkconfig docker on docker run -i -t centos /bin/bash {% endhighlight %}

Congratulations! You are now in a shell of your first docker container.

That was all? Yes!

What’s Next? #

Visit Docker Hub to find the docker image that fits your needs.

As an alternative start building your own docker images. Watch this blog, I have already drafted the next blog post that will explain how to build a custom image.

Take Aways #

Key take-aways while surfing the web for information and specific use-cases:

  • A container does not get configured during run-time. A new image will be build reflecting that configuration change and the current container will be replaced with a new container from that image.
  • A container does just one thing and not more, e.g. provides a database, is a web server, but not being a database and a web server at the same time.

The very most-important key-point which made my virtualization universe whole again:

  • When to use what? - When abstracting a machine, use Vagrant. When abstracting an application, use Docker. Yay!

Further Reading #

Done for today!