Re: is it possible to disable the 3-way merge feature?

["Will Manley" <will williammanley net>]

On Mon, 16 Dec 2019, at 21:22, Davis Roman via ostree-list wrote:

I've often wondered if it is possible to completely disable ostree's 3 way merge feature.

I understand how value this can be for Desktop users however as someone that works on embedded Linux devices, it doesn't provided me much benefit.

I would much rather /etc be slammed to the defaults upon changing to a new ostree commit ( instead of holding on to any previous modifications).

Is there a path available to disable this feature?

I think this would probably involve modifications to ostree sources.  Alternatively you could try replacing /etc with a symlink to a directory under /usr.

You could use `ostree admin diff` to list the local changes and then reset them after doing a deploy.

Like you I use ostree in embedded, but I find the /etc merge feature useful.  Some files are genuinely host-specific, like /etc/machine-id, SSL client certificates, SSH keys, hostname, etc.  The /etc merge feature ensures that these files are preserved across deploys.  Generally I would avoid modifying files in /etc on embedded on a host-by-host basis, but I think adding them won't suffer from the same issues.

As an aside, I've had some ideas about how the /etc merge could be sped up, but I haven't had time to implement them.  On our device a significant proportion of the deploy time is taken up with /etc updates.

Thanks

Will