At the moment, there are three primary commands to be familiar with on
an rpm-ostree based system. Remember that atomic is an alias for
rpm-ostree. The author tends to use the former on client systems,
and the latter on compose servers.
# atomic status
Will show you your deployments, in the order in which they will appear
in the bootloader. The * shows the currently booted deployment.
# atomic upgrade
Will perform a system upgrade, creating a new chroot, and set it as
the default for the next boot. You should use systemctl reboot
shortly afterwards.
# atomic rollback
By default, the atomic upgrade will keep at most two bootable
"deployments", though the underlying technology supports more.
The only writable directories are /etc and /var. In particular,
/usr has a read-only bind mount at all times. Any data in /var is
never touched, and is shared across upgrades.
At upgrade time, the process takes the new default /etc, and adds
your changes on top. This means that upgrades will receive new
default files in /etc, which is quite a critical feature.
- The RPM database is stored in
/usr/share/rpm, and is immutable. - A package nss-altfiles is required,
and the system password database is stored in
/usr/lib/passwd. Similar for the group database.