osbuildbootc

Usage

This tool can be invoked as a pre-built container image, and it can also be installed as a standalone tool inside another environment. The implementation uses qemu+KVM.

Example invocation for the container image:

podman run --rm -ti --security-opt label=disable --device /dev/kvm -v $(pwd):/srv -w /srv ghcr.io/cgwalters/osbuildbootc:latest build-qcow2 -I quay.io/cgwalters/ostest example.qcow2

Explanation of podman arguments:

• --security-opt label=disable: This is necessary to bind mount in host paths at all
• --device /dev/kvm: Pass the KVM device into the container image
• -v $(pwd):/srv -w /srv: Pass the current directory as /srv into the container

Note that by default KVM is required. You can set the OSBUILD_NO_KVM environment variable to use full qemu emulation if necessary.

Take a container image from remote registry, output a qcow2

osbuildbootc build-qcow2 quay.io/centos-bootc/fedora-bootc-cloud:eln fedora-boot-cloud.qcow2

Take a container image stored in local OCI directory

In some scenarios it may be desirable to have local disk caches of container images, instead of fetching from a registry every time.

Note here we need to specify the target image after installtion to ensure that the machine will fetch updates from the registry.

osbuildbootc build-qcow2 --transport oci oci:cgwalters-ostest -I -t quay.io/cgwalters/ostest foo.qcow2

Development

This project is mostly in Go. However, it also has some shell script because some nontrivial code was inherited from coreos-assembler.

It's recommended to use e.g. a toolbox for development:

make && sudo make install

Then you can run osbuildbootc.