/var needs to be read-write for a functioning system. Various
systemd services will fail to start if /var is read-only. After we
remount /var (or if we skip remounting /var because / is read-only),
if /var is still readonly, mount a tmpfs file system on /var.
While this isn't strictly part of ostree, keeping it here makes sense
because it keeps twiddling around with the /var mount in one place
for easier coordination and maintenance. This will likely need updating
if systemd gains better support for a readonly root filesystem.
https://bugzilla.gnome.org/show_bug.cgi?id=732979
The previous S_IMMUTABLE commit broke ostree-remount; / is now not
actually writable. All we really wanted to know though was whether it
was *mounted* writable, so check that via statvfs() which is cleaner
anyways (i.e. not via access() which kernel people hate).
https://bugzilla.gnome.org/show_bug.cgi?id=728006
The idea with this is that things like yum should be able to look for
it and determine whether or not they should assume that they can
change things on the system.
https://bugzilla.gnome.org/show_bug.cgi?id=725380
I ran into Jeremy Katz today, and he gave me permission to relicense
the small bits of switch-root.c to LGPLv2+. This combined with
permission from Peter Jones allows OSTree to become fully LGPLv2+.
Not a big deal, it's just a lot clearer to only have one license, and
it makes it easier to turn application code into library code.
Extracting the code for parse_ostree_cmdline() and running it on some
test input (on RHEL6.4 glibc), I can reproduce the odd behavior from
getline() where it apparently returns the size of the default malloc
buffer in the size output, and some non-zero value.
This behavior would be OK except that it breaks the logic for
stripping off the trailing newline, which in turn breaks booting
because we return "ostree=foo\n".
This has worked so far in gnome-ostree because syslinux apparently
injects initrd=/path/to/initrd as a final kernel argment.
Anyways, we don't handle NUL characters here in /proc/cmdline, so
let's just call strlen () to be safe.
https://bugzilla.gnome.org/show_bug.cgi?id=707192
While the systemd integration effectively requires /sysroot, it will
help people trying to use OSTree with other initramfs systems
(e.g. initramfs-tools) if we don't hardcode that requirement in this
tool.
See https://wiki.gnome.org/OSTree/DeploymentModel2
This is a major rework of the on-disk filesystem layout, and the boot
process. OSTree now explicitly supports upgrading kernels, and these
upgrades are also atomic.
The core concept of the new model is the "deployment list", which is
an ordered list of bootable operating system trees. The deployment
list is reflected in the bootloader configuration; which has a kernel
argument that tells the initramfs (dracut) which operating system root
to use.
Invidiual notable changes that come along with this:
1) Operating systems should now come with their etc in usr/etc; OSTree
will perform a 3-way merge at deployment time, and place etc in
the actual root. This avoids the need for a bind mount, and is
just a lot cleaner.
2) OSTree no longer bind mounts /root, /home, and /tmp. It is expected
that the the OS/ has these as symbolic links into /var.
At the moment, OSTree only supports managing syslinux; other
bootloader backends will follow.
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.
Rather than attempting to hack up the "switch-root" functionality of
systemd, this binary allows us to simply prepare the root before we
switch into it.
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.
Owen W. Taylor
Colin Walters
Adrian Perez