Simplifying Docker Interactions with BASH Aliases

Posted in: DevOps, Technical Track
Landing a Docker Whale

Docker has been consuming my life in the last few weeks. I have half a dozen projects in progress that use containers in some fashion, including my Visualizing MySQL’s Performance Schema project.

Since I prefer to work from a Mac laptop, I have to utilize a Linux Virtual Machine (VM) which runs the Docker daemon. Luckily, Docker Machine makes this a very simple process.

However, interacting both with Docker and Docker Machine does introduce some additional commands that I would rather simplify for the repeatable use-cases I’ve come across. With BASH aliases, this is not a problem.

Is My Docker Environment Setup?

When working with Docker through Docker Machine, you first have to set up your environment with various DOCKER_* variables, such as these:

The first alias is an easy way to check that the Docker environment is setup.

Now, all I have to type is de, and I get the Docker environment output:

Setting up My Docker Environment

But how do you set up the environment with Docker Machine? The docker-machine command provides the details:

Notice that the comments indicate you have to run the command through eval to get the terminal setup correctly. I don’t want to type that out each time I open a new terminal.

The docker-machine command requires the name of the VM to set up as an argument, so I’ve created a function to accept the argument:

Each time I open a terminal I can setup the environment:

If you only use one Docker VM for local development, you can hardcode the name of it to execute the command to automatically setup the docker environment when a new terminal is created.

Cleaning Out Docker Images

The last helpful alias I have comes from building and re-building containers that have left old images on my VM.

The docker-clean command cleans up all dangling images:

And running the docker-clean command yields:

I put all of these aliases and functions together in my ~/.bash_profile* script, which is executed anytime I open a terminal window:

*Note: Instead of putting these aliases and functions in ~/.bash_profile, other distributions would look for them in ~/.bashrc or ~/.bash_aliases to ensure they are available for all types of interactive shells.

If you have any other commands to simplify Docker interactions, please share them in the comments!

 

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2 Comments. Leave new

Glenn Jackman
October 9, 2015 10:09 am

The `dm-env` function can be modified to use a default value:

function dm-env() {
eval “$(docker-machine env “${1:-default}”)”
}

If you do not provide an argument to the function, the string “default” will be used instead. Also, adding quotes as per shell scripting best practices.

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Thanks Glenn, updated!

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