[Pkg-iscsi-maintainers] Bug#833917: open-iscsi: LVM fails to see iSCSI targets for non-mounted devices with systemd.

[Christian Seiler]

Control: tags -1 + moreinfo

On 08/10/2016 12:23 PM, IOhannes m zmllllllnig (Debian/GNU) wrote:
> ## so here's my setup:
> - HOST runs libvirtd/qemu to run a number of virtual machines
> - HOST's system resides on a normal built-in disk
> - additionally, HOST is connected to a SAN via iSCSI
> - HOST has a volumegroup 'virthosts' to manage the disks for the virtual
>   machines. originally the volumegroup only contained local physical devices.
> - HOST hosts a virtual machine FOO, which has a system-disk
>   /dev/virthosts/foo
> - later on an iSCSI LUN has been added to the VG
> - HOST also hosts a virtual machine BAR which has a system-disk
>   /dev/virthosts/bar (which happens to be allocated on the local physical
>   devices) and a data-disk /dev/virthosts/bardata, which has been forced to
>   be allocated on the iSCSI LUN

This should be supported.

> when i reboot the HOST machine LVM gets initialized, obviously *before* the
> iSCSI LUN comes up.

LVM tries to activate as much as possible as early as possible. This
is to be expected and should be OK.

> afaict, the "solution" to this problem would be to add the VG 'virthosts' to
> the LVMGROUPS variable in /etc/default/open-scsi.

Yes, because the init script (and in Stretch onwards the script called
by the native systemd service) calls vgchange -a y $group for each
group in that setting. So that should actually activate the remaining
LVs in your VG. Why it doesn't I'm not sure...

> i suspect this is because the VG is not used (e.g. "mounted") by HOST, but
> instead its LVs are passed on as raw devices to the virtual machines.

No, that has nothing to do with it - mounts are completely irrelevant
here.

Could you give me the output of the following?

journalctl -u open-iscsi

Also, since you upgraded from squeeze could you also check the
following?

md5sum /etc/init.d/open-iscsi
dpkg-query --showformat='${Conffiles}\n' --show open-iscsi

Regards,
Christian