Silverblue - Modifying a file in etc in another deployment

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1

Hello,

I have installed nVidia drivers following the rpmfusion manual. I’m currently playing with config files in /etc/udev/rules.d

The issue is that sometimes, I break the system (e.g not bootable anymore) because I changed a file in /etc and rebooted.

So instead of booting on ostree:0. I switch to ostree:1. From there, I use rpm-ostree rollback. The issue is that I lost all the modifications (packages, stuff in /etc) I’ve done so far (normal as it’s a rollback!).

However what I need is only modifying the offending config file in /etc to make ostree:0 boot again. So the question is:

Given that I booted on ostree:1, can I modify the content of /etc in ostree:0 to go back in a stable state?

Thanks

3

Before I change a file in /etc/udev/rules.d, I make a backup suffixed with _ORG. That way I can quickly roll back any change that causes problems after booting a LiveCD, deleting the bad file and renaming the backup by removing the _ORG suffix.

Although this info does not address your current challenge it may prevent similar ones in the future.

4

Hi,

Unfortunately I’m running Fedora Silverblue and the liveCD trick won’t apply.

Cheers

5

A workaround would be to take your stable deployment, pin it, then perform a minimal change on that deployment, e.g.:

  • layer a small package with rpm-ostree install
    or
  • append a non-impacting kernel argument with rpm-ostree kargs --append.

Either of these actions would create a new deployment similar to the existing one, which you could then tweak to your liking.

The same procedure could be applied to perform modifications incrementally.

sysroot is mounted read-only, so the files from non-booted deployments stored under /sysroot/ostree/deploy/fedora/deploy/ cannot be altered, and that’s a good think.

6

You can look for the copy of /etc for the other deployment in /sysroot/ostree/deploy/fedora/deploy/<long hash>.0/etc (get the hashes from rpm-ostree status). If you want to edit it there, you can remount /sysroot read-write (sudo mount -o remout,rw /sysroot) and do the edits there directly.

1 Like
7

Additionally, if you cannot boot the installed system, you can always boot from a LiveCD, regardless of whether the installation on the disk is in package mode or image mode, i.e. Fedora Workstation or Silverblue.