Example: Use Docker Machine to provision cloud hosts

Docker Machine driver plugins are available for many cloud platforms, so you can use Machine to provision cloud hosts. When you use Docker Machine for provisioning, you create cloud hosts with Docker Engine installed on them.

You’ll need to install and run Docker Machine, and create an account with the cloud provider.

Then you provide account verification, security credentials, and configuration options for the providers as flags to docker-machine create. The flags are unique for each cloud-specific driver. For instance, to pass a Digital Ocean access token, you use the --digitalocean-access-token flag.

As an example, let’s take a look at how to create a Dockerized Digital Ocean Droplet (cloud server).

Step 1. Create a Digital Ocean account and log in

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 clever name (e.g. “machine”), 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 you’ll use in the next step to create your cloud server.

Step 3. Install Docker Machine

If you have not done so already, install Docker Machine on your local host.
- How to install Docker Machine on Mac OS X
- How to install Docker Machine on Windows
- Install Docker Machine directly (e.g., on Linux)

At a command terminal, use docker-machine ls to get a list of Docker Machines and their status.

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

Run some Docker commands to make sure that Docker Engine is also up-and-running.

We’ll run docker run hello-world again, but you could try docker ps, docker run docker/whalesay cowsay boo, or another command to verify that Docker is running.
```
$ docker run hello-world

Hello from Docker.
This message shows that your installation appears to be working correctly.
...
```

Step 4. 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, we’ll call our new Droplet “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

Notice that the new cloud server is running but is not the active host. Our command shell is still connected to the default machine, which is currently the active host as indicated by the asterisk (*).

Run docker-machine env docker-sandbox to get the environment commands for the new remote host, then run eval as directed to re-configure the shell to connect to docker-sandbox.

$ docker-machine env docker-sandbox
export DOCKER_TLS_VERIFY="1"
export DOCKER_HOST="tcp://45.55.222.72:2376"
export DOCKER_CERT_PATH="/Users/victoriabialas/.docker/machine/machines/docker-sandbox"
export DOCKER_MACHINE_NAME="docker-sandbox"
# Run this command to configure your shell:
# eval "$(docker-machine env docker-sandbox)"

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

Re-run docker-machine ls to verify that our new server is the active machine, as indicated by the asterisk (*) in the ACTIVE column.

$ docker-machine ls
NAME             ACTIVE   DRIVER         STATE     URL                         SWARM
default          -        virtualbox     Running   tcp://192.168.99.100:2376   
docker-sandbox   *        digitalocean   Running   tcp://45.55.222.72:2376

Run some docker-machine commands to inspect the remote host. For example, docker-machine ip <machine> gets the host IP adddress 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.

Understand the defaults and options on the create command

For convenience, docker-machine will use sensible defaults for choosing settings such as the image that the server is based on, but you override the defaults using the respective flags (e.g. --digitalocean-image). This is useful if, for example, you want to create a cloud server with a lot of memory and CPUs (by default docker-machine creates a small server). For a full list of the flags/settings available and their defaults, see the output of docker-machine create -h at the command line. See also Driver options and operating system defaults and information about the create command in the Docker Machine documentation.

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, you will see it update 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 will lose track of the server status. So please use the docker-machine rm command for hosts you create with docker-machine --create.

Where to go next

Docker Machine driver reference
Docker Machine Overview
Use Docker Machine to provision hosts on cloud providers
Install Docker Engine
Docker User Guide

Links:

https://docs.docker.com/v1.11/engine/installation/cloud/cloud-ex-machine-ocean/

doc_docker

2017-02-04 08:23:27

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