Re: [Libguestfs] [PATCH INCOMPLETE] daemon: Reimplement LVM filters using lvmdevices command

On Wed, Jun 2, 2021 at 12:23 AM Nir Soffer <nsoffer(a)redhat.com&gt; wrote: > > On Tue, Jun 1, 2021 at 4:38 PM Richard W.M. Jones <rjones(a)redhat.com&gt; wrote: > > > > LVM2 managed to break device filters. This patch attempts a fix. > > > > https://bugzilla.redhat.com/show_bug.cgi?id=1965941 > > > > However it is not working, because the new "lvmdevices" command which > > is supposed to be used to set the new filters does not work for > > partitioned whole devices. As far as I can tell there is no way to > > emulate the old behaviour of filtering such a device. (Adding filters > > for each partition in the device is one possible workaround, but the > > filters will be out of date as soon as a new partition is created on > > the device.) > > The best way to use lvm filter is to use a filter that includes only > the devices you want lvm to use, and reject everything else: > > "a|^/dev/sda1$|", "r|.*|" > > With this there are never any surprises when someone adds a new > device or partition. You need to add the new device to the filter to > use it. > > This is how ovirt configures lvm filter on hosts so they use only the > devices needed by the host and cannot access the devices used by > guests, managed by ovirt. > > ovirt lvm commands override the host filter using: > > --config "device { filter = ["a|^/dev/sdb$|", "r|.*|"] }" > > So it can manage vgs used by ovirt to provide guest disks. > > With --config you don't need to modify the guest when you make changes. The modern way of this with new lvm is simply: --devices /dev/sdb,/dev/sde Right in the lvm command, so you don't need to manage the guest state unless the purpose of the command is to change the state in the guest.