Apko is a command-line tool used to build container images using a declarative language based on YAML. It is inspired by the ko build tool and uses the APK package format. Apko is part of the open-source toolkit developed by Chainguard to build Wolfi and Chainguard Images. Melange is another tool in the same ecosystem that interacts with apko for building apk-based images, using either Alpine or Wolfi as base systems.
To install and manage packages using apko, follow these steps:
- First, you need to define your packages and repositories in a YAML file. Here’s an example:
contents:
repositories:
- https://dl-cdn.alpinelinux.org/alpine/edge/main
packages:
- alpine-base
Save this YAML file in a new file named
Dockerfile.apkoorapko.ymlin your project directory.Install apko by following the getting started guide:
a. If you’re using Debian or Ubuntu, run:
sudo apt-get install apko
b. If you’re using Alpine, run:
apk add apko
- Build your image using apko:
apko build
This command will install all the packages listed in your YAML file and create a new container image.
- To verify the signature of the built image, you can use Sigstore’s cosign tool. First, you need to obtain the image’s certificate:
apko export <image-name> > image.tar.gz
cosign export image.tar.gz > image.tar.gz.crt
Then, you can verify the signature using the following command:
cosign verify-blob <image.tar.gz> --cert image.tar.gz.crt
For more information, you can refer to the official documentation:
- Getting started with apko: https://edu.chainguard.dev/open-source/apko/getting-started-with-apko
- Apko YAML reference: https://edu.chainguard.dev/open-source/apko/reference
- Melange overview: https://edu.chainguard.dev/open-source/melange/overview
- Chainguard Images reference: https://edu.chainguard.dev/chainguard/chainguard-images/reference/apko/image_specs
These resources provide detailed information about using apko, including examples and best practices.
