Getting Started with the pack CLI using Cloud Native Buildpacks

Bryan Friedman

pack is a command line interface (CLI) tool that builds container images locally on your developer machine using Cloud Native Buildpacks.

Before You Begin

There are a few things you need to do before getting started with pack:

Install Docker Desktop. The pack CLI requires the Docker daemon, so you’ll need to have that installed and running locally.
Check out Containers 101 on KubeAcademy, particularly if you’ve never worked with containers or Docker before.
Follow the documentation for installing pack in your local environment.

Using `pack`

Build Image from Working Directory

To generate a container image, use pack build. The following commands will clone a sample Java repository, change to the app directory, and build the container image from this working directory.

git clone https://github.com/buildpacks/samples

cd samples/apps/java-maven

pack build myapp

Build Image from Specified Path

Alternatively, you may point to the app path using the -p option:

git clone https://github.com/buildpacks/samples

pack build myapp -p samples/apps/java-maven

Run Image Locally

After you’ve built your image locally, test it out with Docker using the following command:

docker run --rm -p 8080:8080 myapp

Visit localhost:8080 in your favorite browser to see the app running.

Publish Image to Repository

If you are logged into a container registry from your local machine via Docker Desktop, you can build your image and publish to a remote registry at the same time using the --publish option. Just make sure to clarify the username before the app name:

pack build username/myapp -p samples/apps/java-maven --publish

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