How to add an environment variable to a container in Docker Desktop?

Question

On my first use of Docker Desktop on my Mac, I pulled MySQL from search bar (for Docker Hub presumably), and hit Run. A dialog appeared asking me for configuration options such as port number. I clicked Run to start the container.

I received an error message, saying:

You need to specify one of the following as an environment variable:
- MYSQL_ROOT_PASSWORD
- MYSQL_ALLOW_EMPTY_PASSWORD
- MYSQL_RANDOM_ROOT_PASSWORD

Unfortunately, being new to Docker in general and to Docker Desktop app specifically, I do not know how to set an environment variable after having already established this container within Docker Desktop app.

• I cannot find a way back to that initial configuration dialog where I vaguely recall seeing options for setting environment variables.
• I cannot find any other settings for my now-existing container.

How does one establish environment variables for an existing container within Docker Desktop?

Answer 1

Docker Desktop (or Docker for that matter) doesn't provide an option to add environment variable once your container is up and running, and any additions/changes to environment variables via the docker exec command are limited to that specific session.

I'd recommend you stop and run a new container again, specifically since the error happens when MySQL starts up.

You can set the environment variables when you click on the Images section and click "Run"

Answer 2

In docker desktop there's an option "copy docker run" which will regenerate the command used to run your container:

Then it's easy to add an environment variable by adding --env=NewVaraiable=ItsValue . Just don't add to the end of the generated command since that would run that part as a command inside the new container.