Re: [ovirt-users] thin_check run on VM disk by host on startup ?!

On Wed, Aug 31, 2016 at 11:07 AM, Rik Theys <Rik.Theys(a)esat.kuleuven.be&gt; wrote: > On 08/31/2016 09:43 AM, Rik Theys wrote: >> On 08/30/2016 04:47 PM, Nir Soffer wrote: >>> On Tue, Aug 30, 2016 at 3:51 PM, Rik Theys <Rik.Theys(a)esat.kuleuven.be&gt; wrote: >>>> While rebooting one of the hosts in an oVirt cluster, I noticed that >>>> thin_check is run on the thin pool devices of one of the VM's on which >>>> the disk is assigned to. >>>> >>>> That seems strange to me. I would expect the host to stay clear of any >>>> VM disks. >>> >>> We expect the same thing, but unfortunately systemd and lvm try to >>> auto activate stuff. This may be good idea for desktop system, but >>> probably bad idea for a server and in particular a hypervisor. >>> >>> We don't have a solution yet, but you can try these: >>> >>> 1. disable lvmetad service >>> >>> systemctl stop lvm2-lvmetad.service lvm2-lvmetad.socket >>> systemctl mask lvm2-lvmetad.service lvm2-lvmetad.socket >>> >>> Edit /etc/lvm/lvm.conf: >>> >>> use_lvmetad = 0 >>> >>> 2. disable lvm auto activation >>> >>> Edit /etc/lvm/lvm.conf: >>> >>> auto_activation_volume_list = [] >>> >>> 3. both 1 and 2 >>> >> >> I've now applied both of the above and regenerated the initramfs and >> rebooted and the host no longer lists the LV's of the VM. Since I >> rebooted the host before without this issue, I'm not sure a single >> reboot is enough to conclude it has fully fixed the issue. >> >> You mention that there's no solution yet. Does that mean the above >> settings are not 100% certain to avoid this behaviour? >> >> I was thinking of setting a global_filter in /etc/lvm/lvm.conf to only >> include the PV's for the hypervisor disks (on which the OS is installed) >> so the system lvm commands only touches those. Since vdsm is using its >> own lvm.conf this should be OK for vdsm? > > This does not seem to work. The host can not be activated as it can't > find his volume group(s). To be able to use the global_filter in > /etc/lvm/lvm.conf, I believe it should be overridden in vdsm's lvm.conf > to revert back to the default. > > I've moved my filter from global_filter to filter and that seems to > work. When lvmetad is disabled I believe this should have the same > effect as global_filter? The comments in /etc/lvm/lvm.conf indicate also > udev might ignore the filter setting? Right, global_filter exist so you can override filter used from the command line. For example, hiding certain devices from vdsm. This is why we are using filter in vdsm, leaving global_filter for the administrator. Can you explain why do you need global_filter or filter for the hypervisor disks?

Do you have any issue with the current settings, disabling auto activation and lvmetad?