Linux creates a copy of the soure mount flags when creating a bind
mount; if the source is read-only, then the bind mount is.
The problem is that systemd will remount the rootfs read/write, but
each mount (/home, /var etc.) will still be read-only. We need to
remount every bind mount except for /usr to read-write too.
This only "worked" with the old ostree-switch-root because it
effectively force mounted the rootfs read-write always, ignoring the
"ro" flag.
The real vision of OSTree is to "multiple versions of multiple
operating systems". Up until now, it's worked to install gnome-ostree
inside a host distribution, but several things don't work quite right
if you try to do completely different systems.
In the new model, there's the concept of an "osname" which encompasses
a few properties:
1) Its own /var
2) A set of trees deployed in /ostree/deploy/OSNAME/
3) Its own "current" and "previous" links.
Now it no longer really makes sense to boot with "ostree=current".
Instead, you specify e.g. "ostree=gnome/current".
This is an incompatible change to the deployment code - you will need
to run init-os gnome and redeploy.
All "ostree admin" subcommands now take an OSNAME argument.
First, move deployments to /ostree/deploy. Having them in the
toplevel clutters the filesystem layout too much.
When we deploy a tree like /ostree/deploy/NAME, there is now also a
writable directory /ostree/deploy/NAME-etc. This is mounted as
read-write inside the system.
On an initial install, that directory is copied from
/ostree/deploy/NAME/etc. On subsequent deployments, we find any
changes made in the current deployment's /etc, and apply that set of
changes to the new deployment's /etc.
See https://live.gnome.org/OSTree/EverythingInEtcIsABug
The ostree-switch-root tool expects three arguments (argc=4): new root, OS
tree target, and init(8) binary to launch inside it. Also, the error message
when not enough arguments are passed now tells about the second argument
being the target OS tree.
Reviewed-by: Colin Walters <walters@verbum.org>
Merge the code from ostree-init; now that we're back to targeting an
initramfs (dracut), we don't need to statically link the binary, so
there's no strong reason to have a separate module.
Colin Walters
Adrian Perez