v9.0.4
======
+Upgrading
+---------
+
+* Ceph daemons now run as user and group ceph by default. During upgrade,
+ administrators have two options:
+
+ #. Add the following line to ``ceph.conf`` on all hosts::
+
+ setuser match path = /var/lib/ceph/$type/$cluster-$id
+
+ This will make the daemon remain root (i.e., not drop privileges and
+ switch to user ceph) if the daemon's data directory is still owned by
+ root. Newly deployed daemons will be created with data owned by user
+ ceph and will run with reduced privileges, but upgraded daemons will
+ continue to run as root.
+
+ #. Fix the data ownership during the upgrade. This is the preferred option,
+ but is more work. The process for each host would be to:
+
+ #. Upgrade the ceph package. This creates the ceph user and group.
+ #. Stop the daemon(s)
+ #. Fix the ownership. E.g.,::
+
+ chown -R ceph:ceph /var/lib/ceph/mon/ceph-foo
+ ceph-disk chown /dev/sdb1
+
+ #. Restart the daemon(s)
+
* The on-disk format for the experimental KeyValueStore OSD backend has
changed. You will need to remove any OSDs using that backend before you
upgrade any test clusters that use it.