Working with Docker Machine

Docker Machine is a tool used to create and manage Docker hosts on local machines, cloud providers, or remote servers. Docker Machine allows you to automate the process of setting up Docker on various systems, either locally or remotely. It creates Docker hosts that can be run on different environments like VirtualBox, AWS, Azure, and other cloud platforms.

However, note that Docker Machine is no longer actively maintained, and Docker now recommends using Docker Desktop (for macOS and Windows) or Docker Engine on Linux for managing local Docker environments. That being said, Docker Machine can still be useful for certain use cases, especially for managing remote Docker hosts.

Key Features of Docker Machine:

Provision Docker Hosts: You can create new Docker hosts on local systems, virtual machines, or cloud providers.
Manage Multiple Hosts: Docker Machine allows you to manage multiple Docker hosts with a single CLI.
Run Docker on Virtual Machines: Docker Machine can provision and run Docker inside virtual machines.
Remote Access to Hosts: Once Docker is set up on a remote machine, you can manage it as if it were local.

Installation of Docker Machine

1. Install Docker Machine

If you don't have Docker Machine installed, follow these steps to install it:

macOS and Linux:

curl -L https://github.com/docker/machine/releases/download/v0.16.2/docker-machine-$(uname -s)-$(uname -m) > /usr/local/bin/docker-machine
chmod +x /usr/local/bin/docker-machine

Windows: On Windows, you can use the Docker Toolbox, which includes Docker Machine, or install it through chocolatey If you have it:
```
choco install docker-machine
```

Basic Docker Machine Commands

1. Create a Docker Host (VM)

To create a Docker host (a virtual machine with Docker installed) using Docker Machine, you can specify the provider (e.g., VirtualBox, AWS, etc.). For example:

Create a Docker host using VirtualBox:
```
docker-machine create --driver virtualbox my-docker-host
```
This command will:
- Create a new VM using the VirtualBox driver.
- Install Docker on that VM.
- Name the machine my-docker-host.

Create a Docker host on AWS:

docker-machine create --driver amazonec2 --amazonec2-access-key <AWS_ACCESS_KEY> --amazonec2-secret-key <AWS_SECRET_KEY> --amazonec2-region us-east-1 my-aws-host

Replace <AWS_ACCESS_KEY> and <AWS_SECRET_KEY> With your AWS credentials.

2. List Docker Machines

Once Docker hosts are created, you can list all the available Docker machines:

docker-machine ls

This will display a table with information about each machine, including:

Name: The name of the machine.
Active: Whether the machine is running or stopped.
Driver: The provider (e.g., VirtualBox, AWS).
State: Whether the machine is running, stopped, etc.
URL: The URL to connect to the machine.

3. SSH into a Docker Host

To access the machine via SSH and manage the Docker daemon directly, you can use the following command:

docker-machine ssh my-docker-host

This opens an SSH session into the virtual machine. From here, you can run Docker commands on the remote host.

4. Set Docker Environment Variables for a Machine

To manage the Docker daemon running on a specific machine from your local machine, you need to set the Docker environment variables:

eval $(docker-machine env my-docker-host)

This sets the correct environment variables for the docker CLI to interact with the remote machine, allowing you to run Docker commands on the remote host instead of your local machine.

To verify if the environment is set up correctly, run:

docker info

This will show the Docker information for the remote host (e.g., my-docker-host).

5. Stop and Start Docker Hosts

You can stop and start Docker hosts at any time:

Stop a Docker host:
```
docker-machine stop my-docker-host
```
Start a Docker host:
```
docker-machine start my-docker-host
```

6. Remove a Docker Machine

Once you're done with a Docker machine and no longer need it, you can remove it:

docker-machine rm my-docker-host

This will remove the machine from the Docker Machine inventory and delete the associated virtual machine.

7. Inspect a Docker Machine

You can inspect the machine for details like IP address, Docker version, etc.:

docker-machine inspect my-docker-host

This provides detailed JSON output with information about the machine, including environment variables and its configuration.

Using Docker Machine with Cloud Providers

Docker Machine can provision Docker hosts on various cloud providers like AWS, DigitalOcean, and Azure. You need to have the appropriate API keys and permissions set up.

1. Create a Docker Host on AWS

Here’s an example of creating a Docker host on AWS using Docker Machine:

docker-machine create --driver amazonec2 \
  --amazonec2-access-key <AWS_ACCESS_KEY> \
  --amazonec2-secret-key <AWS_SECRET_KEY> \
  --amazonec2-region us-east-1 \
  my-aws-docker-host

This command will create a Docker machine on AWS using the amazonec2 driver.
Make sure to replace <AWS_ACCESS_KEY> and <AWS_SECRET_KEY> with your actual AWS credentials.

2. Create a Docker Host on DigitalOcean

Docker Machine also supports cloud providers like DigitalOcean. Here’s how you can create a Docker host on DigitalOcean:

docker-machine create --driver digitalocean \
  --digitalocean-access-token <DO_ACCESS_TOKEN> \
  my-do-docker-host

Replace <DO_ACCESS_TOKEN> With your DigitalOcean access token.

3. Create a Docker Host on Azure

You can create a Docker host on Azure by using the Azure driver:

docker-machine create --driver azure \
  --azure-subscription-id <SUBSCRIPTION_ID> \
  --azure-client-id <CLIENT_ID> \
  --azure-client-secret <CLIENT_SECRET> \
  --azure-tenant-id <TENANT_ID> \
  my-azure-docker-host

Replace the placeholders with your actual Azure credentials.

Example: Using Docker Machine with VirtualBox

1. Create a Docker Machine (VM) Using VirtualBox

docker-machine create --driver virtualbox my-docker-vm

2. Set Environment Variables for Remote Docker Host

Once the machine is created, run the following to set up the environment variables for your docker CLI:

eval $(docker-machine env my-docker-vm)

3. Verify the Docker Machine

You can verify the Docker host is accessible by running:

docker info

This will show the information of the Docker daemon running on the my-docker-vm.

4. Access the Docker Machine via SSH

To access the machine via SSH:

docker-machine ssh my-docker-vm

This opens a shell session in the virtual machine running Docker.

Summary of Common Docker Machine Commands

Create a Docker host: docker-machine create --driver <provider> <machine-name>
List Docker hosts: docker-machine ls
SSH into a host: docker-machine ssh <machine-name>
Set Docker environment variables: eval $(docker-machine env <machine-name>)
Stop a Docker host: docker-machine stop <machine-name>
Start a Docker host: docker-machine start <machine-name>
Remove a Docker machine: docker-machine rm <machine-name>
Inspect a Docker machine: docker-machine inspect <machine-name>

Conclusion

While Docker Machine is not actively maintained, it can still be useful for creating and managing Docker hosts across various environments, especially in cloud-based scenarios. For local Docker setups, Docker Desktop or Docker Engine is recommended. However, Docker Machine allows you to manage remote Docker environments easily, whether on VirtualBox, cloud providers, or even your own servers.

Souy Soeng

Working with Docker Machine