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Understanding the Basics of Docker Machine
The Linux Foundation | 12 June 2017
In this series, we’re taking a preview look at the new self-paced Containers for Developers and Quality Assurance (LFS254) training course from The Linux Foundation.
In the first article, we talked about installing Docker and setting up your environment. You’ll need Docker installed to work along with the examples, so be sure to get that out of the way first. The first video below provides a quick overview of terms and concepts you’ll learn.
In this part, we’ll describe how to get started with Docker Machine.
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Docker has a client server-architecture, in which the Client sends the command to the Docker Host, which runs the Docker Daemon. Both the Client and the Docker Host can be in the same machine, or the Client can communicate with any of the Docker Hosts running anywhere, as long as it can reach and access the Docker Daemon.
The Docker Client and the Docker Daemon communicate over REST APIs, even on the same system. One tool that can help you manage Docker Daemons running on different systems from our local workstation is Docker Machine.
If you are using Docker for Mac or Windows, or install Docker Toolbox, then Docker Machine will be available on your workstation automatically. With Docker Machine, we will be deploying an instance on DigitalOcean and installing Docker on that. For that, we would first create our API key from DigitalOcean, with which we can programmatically deploy an instance on DigitalOcean.
After getting the token, we will be exporting that in an environment variable called “DO_TOKEN”, which we will be using in the “docker-machine” command line, in which we are using the “digitalocean” driver and creating an instance called “dockerhost”.
Docker Machine will then create an instance on DigitalOcean, install Docker on that, and configure the secure access between the Docker Daemon running on the “dockerhost” and our client, which is on our workstation. Next, you can use the “docker-machine env” command with our installed host, “dockerhost”, to find the respective parameters with which you can connect to the remote Docker Daemon from your Docker Client.
With the “eval” command, you can export all the environment variables with respect to your “dockerhost” to your shell. After you export the environment variables, the Docker Client on your workstation will directly connect with the DigitalOcean instance and run the commands there. The videos below provide additional details.
In the next article, we will look at some Docker container operations.
This online course is presented almost entirely on video, and the material is prepared and presented by Neependra Khare (@neependra), Founder and Principal Consultant at CloudYuga, Docker Captain, and author of the Docker Cookbook.
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