Digital Ocean example

Estimated reading time: 5 minutes

Follow along with this example to create a Dockerized Digital Ocean Droplet (cloud host).

Step 1. Create a Digital Ocean account

If you have not done so already, go to Digital Ocean, create an account, and log in.

Step 2. Generate a personal access token

To generate your access token:

Go to the Digital Ocean administrator console and click API in the header.
Click Generate new token to get to the token generator.
Give the token a descriptive name, make sure the Write (Optional) checkbox is checked, and click Generate Token.
Grab (copy to clipboard) the generated big long hex string and store it somewhere safe.

This is the personal access token used in the next step to create your cloud server.

Step 3. Use Machine to create the Droplet

Run docker-machine create with the digitalocean driver and pass your key to the --digitalocean-access-token flag, along with a name for the new cloud server.

For this example, the new Droplet is called docker-sandbox:

$ docker-machine create --driver digitalocean --digitalocean-access-token xxxxx docker-sandbox
Running pre-create checks...
Creating machine...
(docker-sandbox) OUT | Creating SSH key...
(docker-sandbox) OUT | Creating Digital Ocean droplet...
(docker-sandbox) OUT | Waiting for IP address to be assigned to the Droplet...
Waiting for machine to be running, this may take a few minutes...
Machine is running, waiting for SSH to be available...
Detecting operating system of created instance...
Detecting the provisioner...
Provisioning created instance...
Copying certs to the local machine directory...
Copying certs to the remote machine...
Setting Docker configuration on the remote daemon...
To see how to connect Docker to this machine, run: docker-machine env docker-sandbox

When the Droplet is created, Docker generates a unique SSH key and stores it on your local system in ~/.docker/machines. Initially, this is used to provision the host. Later, it’s used under the hood to access the Droplet directly with the docker-machine ssh command. Docker Engine is installed on the cloud server and the daemon is configured to accept remote connections over TCP using TLS for authentication.

Go to the Digital Ocean console to view the new Droplet.
At the command terminal, run docker-machine ls.
```
 $ docker-machine ls
 NAME             ACTIVE   DRIVER         STATE     URL                         SWARM
 default          -        virtualbox     Running   tcp://192.168.99.100:2376
 docker-sandbox   *        digitalocean   Running   tcp://45.55.139.48:2376
```
The new docker-sandbox machine is running, and it is the active host as indicated by the asterisk (*). When you create a new machine, your command shell automatically connects to it. If for some reason your new machine is not the active host, run docker-machine env docker-sandbox, followed by eval $(docker-machine env docker-sandbox) to connect to it.

Step 4. Run Docker commands on the Droplet

Run some docker-machine commands to inspect the remote host. For example, docker-machine ip <machine> gets the host IP address and docker-machine inspect <machine> lists all the details.

 $ docker-machine ip docker-sandbox
 104.131.43.236

 $ docker-machine inspect docker-sandbox
 {
     "ConfigVersion": 3,
     "Driver": {
     "IPAddress": "104.131.43.236",
     "MachineName": "docker-sandbox",
     "SSHUser": "root",
     "SSHPort": 22,
     "SSHKeyPath": "/Users/samanthastevens/.docker/machine/machines/docker-sandbox/id_rsa",
     "StorePath": "/Users/samanthastevens/.docker/machine",
     "SwarmMaster": false,
     "SwarmHost": "tcp://0.0.0.0:3376",
     "SwarmDiscovery": "",
     ...

Verify Docker Engine is installed correctly by running docker commands.

Start with something basic like docker run hello-world, or for a more interesting test, run a Dockerized webserver on your new remote machine.

In this example, the -p option is used to expose port 80 from the nginx container and make it accessible on port 8000 of the docker-sandbox host.
```
 $ docker run -d -p 8000:80 --name webserver kitematic/hello-world-nginx
 Unable to find image 'kitematic/hello-world-nginx:latest' locally
 latest: Pulling from kitematic/hello-world-nginx
 a285d7f063ea: Pull complete
 2d7baf27389b: Pull complete
 ...
 Digest: sha256:ec0ca6dcb034916784c988b4f2432716e2e92b995ac606e080c7a54b52b87066
 Status: Downloaded newer image for kitematic/hello-world-nginx:latest
 942dfb4a0eaae75bf26c9785ade4ff47ceb2ec2a152be82b9d7960e8b5777e65
```
In a web browser, go to http://<host_ip>:8000 to bring up the webserver home page. You got the <host_ip> from the output of the docker-machine ip <machine> command you ran in a previous step. Use the port you exposed in the docker run command.

Step 5. Use Machine to remove the Droplet

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

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

$ docker-machine ls
NAME      ACTIVE   DRIVER       STATE     URL                         SWARM
default   *        virtualbox   Running   tcp:////xxx.xxx.xx.xxx:xxxx

If you monitor the Digital Ocean console while you run these commands, notice that it updates first to reflect that the Droplet was stopped, and then removed.

If you create a host with Docker Machine, but remove it through the cloud provider console, Machine loses track of the server status. Use the docker-machine rm command for hosts you create with docker-machine create.

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