docs/docs/get-started-cloud.md

Using Docker Machine with a cloud provider

Creating a local virtual machine running Docker is useful and fun, but it is not the only thing Docker Machine is capable of. Docker Machine supports several “drivers” which let you use the same interface to create hosts on many different cloud or local virtualization platforms. This is accomplished by using the docker-machine create command with the --driver flag. Here we will be demonstrating the Digital Ocean driver (called digitalocean), but there are drivers included for several providers including Amazon Web Services, Google Compute Engine, and Microsoft Azure.

Usually it is required that you pass account verification credentials for these providers as flags to docker-machine create. These flags are unique for each driver. For instance, to pass a Digital Ocean access token you use the --digitalocean-access-token flag.

Let's take a look at how to do this.

To generate your access token:

1. Go to the Digital Ocean administrator console and click on "API" in the header.
2. Click on "Generate New Token".
3. Give the token a clever name (e.g. "machine"), make sure the "Write" checkbox is checked, and click on "Generate Token".
4. Grab the big long hex string that is generated (this is your token) and store it somewhere safe.

Now, run docker-machine create with the digitalocean driver and pass your key to the --digitalocean-access-token flag.

Example:

$ docker-machine create \
    --driver digitalocean \
    --digitalocean-access-token 0ab77166d407f479c6701652cee3a46830fef88b8199722b87821621736ab2d4 \
    staging
Creating SSH key...
Creating Digital Ocean droplet...
To see how to connect Docker to this machine, run: docker-machine env staging

For convenience, docker-machine will use sensible defaults for choosing settings such as the image that the VPS is based on, but they can also be overridden using their respective flags (e.g. --digitalocean-image). This is useful if, for instance, you want to create a nice large instance with a lot of memory and CPUs (by default docker-machine creates a small VPS). For a full list of the flags/settings available and their defaults, see the output of docker-machine create -h.

When the creation of a host is initiated, a unique SSH key for accessing the host (initially for provisioning, then directly later if the user runs the docker-machine ssh command) will be created automatically and stored in the client's directory in ~/.docker/machines. After the creation of the SSH key, Docker will be installed on the remote machine and the daemon will be configured to accept remote connections over TCP using TLS for authentication. Once this is finished, the host is ready for connection.

To prepare the Docker client to send commands to the remote server we have created, we can use the subshell method again:

$ eval "$(docker-machine env staging)"

From this point, the remote host behaves much like the local host we created in the last section. If we look at docker-machine ls, we'll see it is now the "active" host, indicated by an asterisk (*) in that column:

$ docker-machine ls
NAME      ACTIVE   DRIVER         STATE     URL
dev       -        virtualbox     Running   tcp://192.168.99.103:2376
staging   *        digitalocean   Running   tcp://104.236.50.118:2376

To remove a host and all of its containers and images, use docker-machine rm:

$ docker-machine rm dev staging
Do you really want to remove "dev"? (y/n): y
Successfully removed dev
Do you really want to remove "staging"? (y/n): y
Successfully removed staging

$ docker-machine ls
NAME      ACTIVE   DRIVER       STATE     URL

Adding a host without a driver

You can add a host to Docker which only has a URL and no driver. Therefore it can be used an alias for an existing host so you don’t have to type out the URL every time you run a Docker command.

$ docker-machine create --url=tcp://50.134.234.20:2376 custombox
$ docker-machine ls
NAME        ACTIVE   DRIVER    STATE     URL
custombox   *        none      Running   tcp://50.134.234.20:2376

Using Docker Machine with Docker Swarm

Docker Machine can also provision Swarm clusters. This can be used with any driver and will be secured with TLS.

First, create a Swarm token. Optionally, you can use another discovery service. See the Swarm docs for details.

To create the token, first create a Machine. This example will use VirtualBox.

$ docker-machine create -d virtualbox local

Load the Machine configuration into your shell:

$ eval "$(docker-machine env local)"

Then run generate the token using the Swarm Docker image:

$ docker run swarm create
1257e0f0bbb499b5cd04b4c9bdb2dab3

Once you have the token, you can create the cluster.

Swarm master

Create the Swarm master:

docker-machine create \
    -d virtualbox \
    --swarm \
    --swarm-master \
    --swarm-discovery token://<TOKEN-FROM-ABOVE> \
    swarm-master

Replace <TOKEN-FROM-ABOVE> with your random token. This will create the Swarm master and add itself as a Swarm node.

Swarm nodes

Now, create more Swarm nodes:

docker-machine create \
    -d virtualbox \
    --swarm \
    --swarm-discovery token://<TOKEN-FROM-ABOVE> \
    swarm-node-00

You now have a Swarm cluster across two nodes. To connect to the Swarm master, use eval $(docker-machine env --swarm swarm-master)

For example:

$ docker-machine env --swarm swarm-master
export DOCKER_TLS_VERIFY=1
export DOCKER_CERT_PATH="/home/ehazlett/.docker/machines/.client"
export DOCKER_HOST=tcp://192.168.99.100:3376

You can load this into your environment using eval "$(docker-machine env --swarm swarm-master)".

Now you can use the Docker CLI to query:

$ docker info
Containers: 1
Nodes: 1
 swarm-master: 192.168.99.100:2376
  └ Containers: 2
  └ Reserved CPUs: 0 / 4
  └ Reserved Memory: 0 B / 999.9 MiB