How to use docker buildx stop command to manage builder instances

Introduction

In this lab, you will learn how to manage Docker builder instances using the docker buildx stop command. We will cover the essential steps to effectively control the lifecycle of your builder environments.

Specifically, you will learn how to create a new builder instance, stop the default builder instance, and stop a specific builder instance by its name. This hands-on experience will equip you with the skills to manage different build configurations and optimize your Docker image building process.

Skills Graph

Create a new builder instance

In this step, we will learn how to create a new builder instance in Docker. A builder instance is a backend for building Docker images. By default, Docker uses a single builder instance, but you can create new instances with different configurations, such as using a different build driver or connecting to a remote builder.

To create a new builder instance, we use the docker buildx create command. This command allows us to specify various options for the new instance, such as the name, driver, and endpoint.

Let's create a new builder instance named mybuilder. We will use the default docker driver, which uses the Docker daemon to build images.

docker buildx create --name mybuilder

After running this command, Docker will create a new builder instance with the specified name. You should see output similar to this:

mybuilder

This output confirms that the mybuilder instance has been created.

Now, let's verify that the new builder instance has been created successfully. We can use the docker buildx ls command to list all available builder instances.

docker buildx ls

The output of this command will show a list of builder instances, including the default one and the new mybuilder instance we just created. Look for the mybuilder entry in the list.

NAME/NODE       DRIVER/ENDPOINT STATUS  BUILDKIT
default         docker
  default       default         running v0.10.5
mybuilder       docker
  mybuilder     default         running v0.10.5

In the output, you can see that mybuilder is listed with the docker driver and a status of running. This indicates that the new builder instance is ready to be used.

Stop the default builder instance

In this step, we will learn how to stop the default builder instance in Docker. The default builder instance is the one that Docker uses by default for building images. Sometimes, you might need to stop it, for example, if you want to switch to a different builder instance or troubleshoot issues.

To stop a builder instance, we use the docker buildx stop command followed by the name of the instance. The default builder instance is typically named default.

Let's stop the default builder instance.

docker buildx stop default

After running this command, Docker will attempt to stop the default builder instance. If the instance is running, it will be stopped. You might not see any output if the command is successful.

Now, let's verify that the default builder instance has been stopped. We can use the docker buildx ls command again to list the builder instances and check their status.

docker buildx ls

Look at the output of the docker buildx ls command. The status of the default builder instance should now be stopped or it might not appear in the list of running instances.

NAME/NODE       DRIVER/ENDPOINT STATUS  BUILDKIT
default         docker
  default       default         stopped
mybuilder       docker
  mybuilder     default         running v0.10.5

In the output above, you can see that the status for the default node under the default builder is now stopped. This confirms that the default builder instance has been successfully stopped.

Stop a specific builder instance by name

In this step, we will learn how to stop a specific builder instance by its name. In the previous steps, we created a new builder instance named mybuilder. Now, we will stop this specific instance.

Similar to stopping the default instance, we use the docker buildx stop command, but this time we provide the name of the specific instance we want to stop.

Let's stop the mybuilder instance.

docker buildx stop mybuilder

After executing this command, Docker will stop the mybuilder instance. Again, you might not see any output if the command is successful.

To confirm that the mybuilder instance has been stopped, we can use the docker buildx ls command to list the builder instances and check their status.

docker buildx ls

Examine the output of the docker buildx ls command. The status of the mybuilder instance should now be stopped.

NAME/NODE       DRIVER/ENDPOINT STATUS  BUILDKIT
default         docker
  default       default         stopped
mybuilder       docker
  mybuilder     default         stopped

As you can see in the output, the status for the mybuilder node under the mybuilder builder is now stopped. This confirms that we have successfully stopped the specific builder instance by its name.

Summary

In this lab, we learned how to manage Docker builder instances using the docker buildx command. We started by creating a new builder instance named mybuilder using docker buildx create --name mybuilder and verified its creation with docker buildx ls.

We then explored how to stop builder instances. The lab demonstrated how to stop the default builder instance and how to stop a specific builder instance by its name. These steps are crucial for managing the lifecycle of your Docker build environments.