Mandi! Alwin Antreich
In chel di` si favelave...
not a ceph expert, but solution iii) seems decent for me, with a
little overhead (a readlinkk and a stat for every osd start).
However you like it.
But to note that in Ceph Nautilus the udev rules
aren't shipped anymore.
Ok. I make a note.
i don't understood why, if i have:
(so, journal partition group-owned by 'disk' and 'ceph' user in group
'disk'), still i have permission access.
The ceph-osd process reset group ownership on runtime?
In Luminous udev is
handling all of that, see 95-ceph-osd.rules.
No, sorry, evidently i'm not explaining myself correctly.
I've added the 'ceph' user to group 'disk':
> root@capitanmarvel:~# LANG=C id ceph
> uid=64045(ceph) gid=64045(ceph) groups=64045(ceph),6(disk)
and journal devices are group-owned by 'disk' and have read and write
permission for the group (660):
> brw-rw---- 1 root disk 8, 6 ago 28 14:38
So, because user 'ceph' are in group 'disk', and group 'disk'
and write permission to the device, i can ACTUALLY read and write to
the device. But is not the case.
So, seems to me that 'ceph-osd' process ''reset'' group
ignore the 'disk' group.
Note, that if i 'su' to ceph, i can read the disks:
The ceph-osd process
runs with user and group ceph and this is why it wants
the group on the disk to be ceph as well.
ps xa -o user,group,command | grep ceph-osd
You would need to change the service template and alter the setgroup to
'disk' or 'ceph' to make it work.
-- 8< --
└─7643 /usr/bin/ceph-osd -f --cluster ceph --id 1 --setuser ceph --setgroup
-- 8< --
I still recommend to go with an extra SSD and spare the hassle.