On 03/02/2018 08:28 AM, Peter Krempa wrote:
On Tue, Feb 27, 2018 at 09:53:00 +0100, Michal Privoznik wrote:
> On 02/27/2018 03:06 AM, Star Guo wrote:
>> Hello Everyone,
>>
>>
>>
>> My pc run in CentOS 7.4 and install libvirt-4.0.0 + Qemu-kvm 2.9.0 + Ceph
>> 10.2.10 ALL-in-One.
>>
>>
>>
>> I use python-sdk with libvirt and run [self.domain.updateDeviceFlags(xml,
>> libvirt.VIR_DOMAIN_AFFECT_LIVE)] on CDROM (I want to change media path).
>> However, I enable libvirt debug log , the log as below:
>>
>> <snip/>
>>
>> I see the flow is virDomainUpdateDeviceFlags -> qemuMonitorChangeMedia, but
>> the cephx auth is drop, so make update error. Anybody meet this error?
>
> Yes, this is a libvirt bug. I think this fixes the issue:
>
> diff --git i/src/qemu/qemu_driver.c w/src/qemu/qemu_driver.c
> index 96454c17c..0e5ad9971 100644
> --- i/src/qemu/qemu_driver.c
> +++ w/src/qemu/qemu_driver.c
> @@ -7842,6 +7842,8 @@ qemuDomainChangeDiskLive(virDomainObjPtr vm,
> virQEMUDriverPtr driver,
> bool force)
> {
> + virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
> + qemuDomainObjPrivatePtr priv = vm->privateData;
> virDomainDiskDefPtr disk = dev->data.disk;
> virDomainDiskDefPtr orig_disk = NULL;
> virDomainDeviceDef oldDev = { .type = dev->type };
> @@ -7850,6 +7852,9 @@ qemuDomainChangeDiskLive(virDomainObjPtr vm,
> if (virDomainDiskTranslateSourcePool(disk) < 0)
> goto cleanup;
>
> + if (qemuDomainPrepareDiskSource(disk, priv, cfg) < 0)
> + goto cleanup;
It's not that easy. At this point you also need to hotplug the 'secret'
object. Without that the command will fail as the secret object
referenced by the storage source definition will not be present.
Just because it may not be obvious that the thread forked (probably
email client for original poster)... Anyway, see what ended up being a
longer explanation here:
https://www.redhat.com/archives/libvirt-users/2018-February/msg00086.html
Where the short story is I don't think you need to hotplug a secret
object as that should already be there. One cannot hotplug a cdrom, so
the definition and the secret used must already exist. It's a strange
code path and while looking I didn't find a mechanism that would allow
an "empty" or "tray='open'" to actually create a dummy entry.
I believe there needs to be a way via the (newer, but not supported in
libvirt) blockdev-change-medium qmp command to tell it what the secret
object id is.
There should be a upstream bugzilla tracking this and I'm planing
to fix
this during my work on using the new blockdev stuff in qemu.
And yes, bzs would be good to track all this.
John