Comment 0 for bug 1716825

Steve Langasek (vorlon) wrote :

[SRU Justification]
plymouth declares a dependency on initramfs-tools | dracut. Plymouth does not require that the system use an initramfs, it only hooks into the initramfs if it's present and if plymouth is needed for prompting prior to mounting the root filesystem.

We should drop this dependency, to support building of images with initramfs-tools removed for systems that we know don't require an initramfs.

[Test case]
1. On a default cloud image install, try to run 'sudo apt purge initramfs-tools'.
2. Verify that this tries to remove plymouth.
3. Cancel the removal.
4. Install plymouth from xenial-proposed.
5. Run 'sudo apt purge initramfs-tools' again.
6. Verify that plymouth is not removed.
7. Run 'sudo apt install --reinstall plymouth' and confirm that the package can be installed successfully without initramfs-tools installed.

[Regression Potential]
If a user needs an initramfs in order to mount their root device (whether or not it's on RAID), and plymouth is the only package on their system which depends on initramfs-tools, it is possible that the user may remove initramfs-tools and render their system unbootable.

This is unlikely because initramfs-tools is still part of the 'minimal' seed and is therefore a dependency of ubuntu-minimal; and it remains a dependency of the generic kernel image.

So long as initramfs-tools is installed, plymouth's initramfs hooks will continue to function as intended when required.