Using Docker Machine

In this workshop we'll run through what the docker-machine command line tool, what it is and how to use it to provision a machine with the Docker Engine installed automatically. Our tutorial will be in the context of deploying a VM in Microsoft Azure.

Requirements

• Docker tools:
  • Docker for Mac (includes docker, docker-machine and docker-compose)
  • Docker for Windows (includes docker, docker-machine and docker-compose)
  • Azure Cloud Shell
    • If you have an Azure Account, you can access a free Ubuntu Bash Shell from the Azure Portal in a web browser
    • Includes the require docker tooling, Azure-CLI and other tools
• Optional
  • Azure-CLI to view/create/modify Azure Specific Resources

What is docker-machine

Docker provides various command line tools. The docker command (aka "docker client") is the most utilized one, and is used to deploy containers to your target docker host environment. You can consider docker-machine a docker host provisioning tool. It helps you to provision a machine (Azure VM in our examples) and install docker onto it with one command line tool. You can remotely connect to the provisioned Docker host using docker-machine ssh <docker_host_name> command to directly performing administrative tasks on that target host. See below for additional commands.

Basic commands

Create VM and install Docker

docker-machine create \
    --driver azure \
    --azure-subscription-id <azure_subscription_id> \
    --azure-image <azure_image> \
    --azure-vm-size <azure_vm_size> \
    --azure-resource-group <azure_resource_group> \
    --azure-location <azure_datacentre_location> \
    <new_vm_name>

Parameter flags explained

• --driver or -d specifies the provider driver to use (Azure in our case)
• --azure-subscription-id specifiy the azure subscription/account id you wish to deploy to (you may have multiple billing subscription/accounts associated to you)
• --azure-image specifiy the type of OS Image you wish to deploy. Follows the same naming format ("Urn" format) as Azure-CLI/ARM template e.g. "Canonical:UbuntuServer:14.04.5-LTS:latest"
• --azure-vm-size specify the size of the VM you wish to deploy including quotes. Follows the same naming format as Azure-CLI/ARM template e.g. "Standard_D1_v2"
• --azure-resource-group OPTIONALLY specify the azure resource group to deploy your VM to. This vm can be an existing one or a new one. If left out, defaults to "docker-machine" as the resource group to deploy or create.
• --azure-location specifiy the Azure datacentre location to deploy to e.g. "canadacentral"
• <vm_name> specify the name of the new VM to be deployed. This will be used as the name to connect to the vm and the VM's hostname.

List all created docker-machine host machines

docker-machine ls

Connect (SSH) to new VM

docker-machine ssh <vm_name>

The docker-machine command creates and saves a new ssh-key pair for each new VM you create via the command. This helps to not pollute/expose any other keys you may have and keeps it organized.

Use your VM as the default target of the docker command

eval $(docker-machine env <vm_name>)

This will export the required environment variables into your current shell session that the docker command needs to connect to the remote VM. To see the output simply run the command without the "eval $()" i.e. docker-machine env <vm_name>.

Other resources

• Blog Post ORCHESTRATING DOCKER WITH MACHINE, SWARM AND COMPOSE by Ben Firshman