We want to support extending the read-only state to cover `/sysroot`
and `/boot`, since conceptually all of the data there should only
be written via libostree. Or at least for `/boot` should *mostly*
just be written by ostree.
This change needs to be opt-in though to avoid breaking anyone.
Add a `sysroot/readonly` key to the repository config which instructs
`ostree-remount.service` to ensure `/sysroot` is read-only. This
requires a bit of a dance because `/sysroot` is actually the same
filesystem as `/`; so we make `/etc` a writable bind mount in this case.
We also need to handle `/var` in the "OSTree default" case of a bind
mount; the systemd generator now looks at the writability state of
`/sysroot` and uses that to determine whether it should have the
`var.mount` unit happen before or after `ostree-remount.service.`
Also add an API to instruct the libostree shared library
that the caller has created a new mount namespace. This way
we can freely remount read-write.
This approach extends upon in a much better way previous work
we did to support remounting `/boot` read-write.
Closes: https://github.com/ostreedev/ostree/issues/1265
It's a neat way to point folks to the documentation (of course, better
would be to have man pages for each of those services). Also
consistently use Title Case everywhere.
Closes: #1750
Approved by: cgwalters
This is standard practice for units like this; e.g. it's what
`systemd-remount-fs.service` does. I think it may be part of
or the whole cause for
https://github.com/projectatomic/rpm-ostree/issues/1471
I haven't reproduced the problem exactly but it seems to me that
if the unit starts and is GC'd, then when systemd goes to execute
a later unit it might end up restarting it.
A noticeable side effect of this is that `systemctl status ostree-remount`
exits with code `0` as expected.
Closes: #1697
Approved by: jlebon
Follow systemd units in using emergency.target, not emergency.service
(which is the sole unit, by default, in emergency.target) so we can
easily reconfigure the units which are actived when entering
emergency mode.
Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
Closes: #1665
Approved by: cgwalters
Why not to use libexecdir?
Because this directory does not exist on some distros or paths
between distros varies. There are several reasons why a well
known path is prefered, for example when generating a kernel
command line:
init=${ostree}/usr/lib/ostree-boot/ostree-prepare-root
In addition this saves us some typing in a console when wanting
to access the "ostree" cmd line.
Closes: #449
Approved by: cgwalters
tmpfiles.d configurations generally require write access to some places
that are read-only until ostree-remount runs.
Make sure ostree-remount has run first.
Thanks to Cosimo Cecchi for finding and diagnosing this problem.
https://bugzilla.gnome.org/show_bug.cgi?id=724183
Joseph Marrero
Jonathan Lebon
Simon McVittie
Colin Walters
Alex Kiernan
Gatis Paeglis
Daniel Drake
Daniel Narvaez