How to use docker buildx rm command to remove builder instances

Introduction

In this lab, we will learn how to manage Docker builder instances using the docker buildx rm command. We will begin by creating a new builder instance to work with.

Following the creation, we will verify its successful creation by listing all available builder instances. Finally, we will demonstrate how to remove a specific builder instance and also how to remove all inactive builder instances efficiently.

Skills Graph

Create a new builder instance

In this step, we will learn how to create a new builder instance using the docker buildx create command. A builder instance is a Docker object that allows you to build images using BuildKit, which provides enhanced performance and features compared to the traditional Docker builder.

First, let's check if you have any existing builder instances. You can do this by listing them:

docker buildx ls

If this is your first time using buildx, you likely won't see any custom builder instances listed, only the default one.

Now, let's create a new builder instance named mybuilder. We will use the default driver, which is docker-container.

docker buildx create --name mybuilder

This command creates a new builder instance with the specified name. You should see output indicating that the builder instance has been created.

List builder instances to confirm creation

In the previous step, we created a new builder instance named mybuilder. Now, let's verify that the builder instance was successfully created by listing all available builder instances.

We can use the docker buildx ls command again to list the builder instances.

docker buildx ls

You should now see mybuilder listed in the output, along with the default builder instance. The output will show the name, driver, and status of each builder instance. The status of mybuilder should be running or inactive.

This command is useful for seeing all your configured builder instances and their current state.

Remove the newly created builder instance

In this step, we will remove the builder instance named mybuilder that we created in the previous steps. This is useful for cleaning up builder instances that are no longer needed.

To remove a builder instance, we use the docker buildx rm command followed by the name of the builder instance.

docker buildx rm mybuilder

You should see output confirming that the builder instance has been removed.

After removing the builder instance, you can list the builder instances again to confirm that mybuilder is no longer present in the list.

docker buildx ls

This command should now only show the default builder instance.

Remove all inactive builder instances without confirmation

In this final step, we will learn how to remove all inactive builder instances without being prompted for confirmation. This is a quick way to clean up any builder instances that are not currently in use.

To remove all inactive builder instances, we use the docker buildx prune command. By default, this command will ask for confirmation before removing anything. To skip the confirmation prompt, we can use the -f or --force flag.

docker buildx prune -f

This command will remove all builder instances that are currently in an inactive state. You should see output indicating which builder instances were removed.

After running the prune command, you can list the builder instances again to confirm that all inactive instances have been removed.

docker buildx ls

You should now only see the default builder instance, unless you have other active builder instances.

Summary

In this lab, we learned how to manage Docker builder instances using the docker buildx command. We began by creating a new builder instance named mybuilder using docker buildx create, which allows for enhanced image building capabilities with BuildKit. We then confirmed the successful creation of this instance by listing all available builders with docker buildx ls, observing mybuilder in the output alongside the default builder.

Finally, we practiced removing builder instances. We first removed the specific mybuilder instance using docker buildx rm mybuilder. The lab also introduced the concept of removing all inactive builder instances without confirmation, although the full steps for this were not provided in the provided content. This lab provided practical experience in the lifecycle management of Docker builder instances.