Container-storage BTRFS loopback

Author: Zeglius

Description: Mount container-storage in a btrfs loopback for space restrained environments

Inputs

target-dir

• Description: Path to the container-storage directory. Defaults to the user container-storage (~/.local/share/containers)
• Required: No
• Default: ""
• Note: Set to /var/lib/containers in case of using rootful podman, /var/lib/docker if using docker.

mount-opts

• Description: Mount options for the BTRFS loopback, separated by commas
• Required: No
• Default: ""

loopback-free

• Description: Percentage of the total space to use for the loopback. Max: 1.0, Min: 0.0
• Required: No
• Default: "0.8"

Usage

To use this action, add the following to your workflow file:

- name: Mount BTRFS loopback
  uses: zeglius/container-storage-action@v1 # Replace v1 with the desired tag or commit hash
  with:
    target-dir: /var/lib/containers
    mount-opts: compress-force=zstd:2
    loopback-free: 0.5

How it works

This action executes the mount_btrfs.sh script, which performs the following steps:

1. Determines Target Directory: It first determines the target-dir for the container storage. If not provided, it defaults to the podman system info's graph root.
2. Installs btrfs-progs: Ensures that the btrfs-progs package is installed on the system.
3. Creates Loopback File: A loopback file is created based on the available free space in the directory where the loopback file will reside. The size is determined by the loopback-free input.
4. Formats Loopback File: The created loopback file is then formatted as a BTRFS filesystem.
5. Mounts Loopback: Finally, the BTRFS loopback file is mounted to the target-dir using systemd-mount, applying any specified mount-opts.

License

This project is licensed under the Apache License, Version 2.0 - see the LICENSE file for details.