Docker Machine, Compose & Swarm

Since I last properly [wrote about Docker](/2014/08/31/docker-fig-nginx-reverse-proxies-and-centos-7/“Docker, Fig, NGINX Reverse Proxies and CentOS 7”) a lot has changed. Docker have introduced some new command line tools which allow for easy orchestration of Docker instances, clusters and container management. These are;

• Docker Machine↗  — Allows you to easily deploy Docker instances to a lot of different platforms.
• Docker Compose↗  — A replacement for Fig↗ .
• Docker Swarm↗  — Native clustering for your Docker instances.

Out of these three technologies, Swarm is not really suitable for production use so I won’t go into it in too much detail in this post.

Docker Machine

Rather than downloading the pre-compiled binary I decided to use the Homebrew↗ formula (this assumes you have Cask installed);

This will install docker-machine;

I already have VirtualBox↗ installed so lets create a machine called “Testing”;

docker-machine comes with a few commands which will help you connect using the locally installed docker client;

Thats it, I now have a Virtual Machine launched and ready for me to start using Docker;

As with any new installation, lets run a “Hello World”↗ ;

Finally you can SSH to the Virtual Machine using docker-machine ssh machine-name;

Great, so I now have a Virtual Machine running on my local computer, what more is there?

docker-machine is designed to be used with the following public and private cloud providers (more are being added all of the time);

• Amazon EC2
• Microsoft Azure
• Digital Ocean
• Google Compute Engine
• Rackspace
• SoftLayer
• OpenStack
• VMWare vCloud Air
• VMWare vSphere

Lets use docker-machine to launch aDigital Ocean↗droplet. To do this you will need to generate a Personal Access Token, you can do this byfollowing these instructions↗. Once have the token launch the droplet as follows;

(and no, that is not my Digital Ocean Personal Access Token, it’s just a random string)

So what just happened? docker-machine accessed my Digital Ocean account via the API and launched the following Droplet;

• OS = Ubuntu 14.04 x64
• RAM = 512MB
• HDD = 20GB SSD
• Region = NYC3

These defaults can be over-ridden by providing more options, run docker-machine create — help for a full break down of the options along with example arguments.

Once the droplet had finished booting, docker-machine connected to the droplet via SSH installed, configured and started the latest version of Docker.

So, we now have two machines launched, one locally and one in Digital Ocean;

lets run the “hello world” again, but this time use the droplet which has just been launched;

and finally SSH into the machine;

Finally, you can stop and remove machines using docker-machine stop machine-name and docker-machine rm machine-name, be careful when using rm as it does not prompt you if you are sure;

So thats a quick overview of docker-machine. As you can see, it is a a really convenient way to bootstrap Docker server instances across many different providers and tear them down all using a single command from your local machine.

Docker Compose

Docker Compose started life as Fig which is something [I have written about before in a previous post](/2014/08/31/docker-fig-nginx-reverse-proxies-and-centos-7/“Docker, Fig, NGINX Reverse Proxies and CentOS 7”), the currently release doesn’t add too much in the way of new functionality, but it does start laying the foundations for working with docker-swam,click here↗for the full release notes.

Like docker-machine I installed it using aHomebrew↗formula;

So using docker-machine lets create a Docker server instance to use docker-compose with;

as docker-compose doesn’t interact directly with docker-machine we need to tell the main docker client the details of the server instance which has just been launched;

this command injects the environment variables needed for the docker client to connect to the server instance, to see these you can just run docker-machine env machine-name on it’s own;

From here, it is just like Fig, apart from fig.yml file should now be called docker-compose.yml, I had a fig.yml file from a previous post still on my machine;

It launches two containers and links them together along with mounting the ./web folder in the NGINX container. The directory structure of the folder I am going to be running docker-compose from looks like;

To start with I pulled the images which are going to be launched, you can ignore this part, it just makes showing whats going on in this post more straight forward;

Now the images have been pulled down it’s time to launch the containers;

We now have two running containers;

You can also open your browser using;

In my example I see aphpinfo()↗page.

Once the containers are running you can connect to them using docker exec;

Finally you can stop and remove the containers, and the Docker instance;

Docker Swarm

Before going any further, the documentation warns ….

Note: Swarm is currently in beta, so things are likely to change. We don’t recommend you use it in production yet.

Now that’s out of the way lets useHomebrew↗to install docker-swarm;

As we already have docker-machine installed I will be using it to locally create the cluster, first of all we need to launch an instance and run the swarm container;