[libvirt-users] live migration and config

[Dmitry Melekhov]

14.09.2018 15:43, Jiri Denemark пишет:
> On Thu, Sep 13, 2018 at 19:37:00 +0400, Dmitry Melekhov wrote:
>>
>> 13.09.2018 18:57, Jiri Denemark пишет:
>>> On Thu, Sep 13, 2018 at 18:38:57 +0400, Dmitry Melekhov wrote:
>>>> 13.09.2018 17:47, Jiri Denemark пишет:
>>>>> On Thu, Sep 13, 2018 at 10:35:09 +0400, Dmitry Melekhov wrote:
>>>>>> After some mistakes yesterday we ( me and my colleague ) think that it
>>>>>> will be wise for libvirt to check config file existence on remote side
>>>>> Which config file?
>>>>>
>>>> VM config file, namely qemu.
>>> Do you mean the domain XML definition found in /etc/libvirt/qemu/*.xml ?
>> Yes and no, xml, but at another location.
>>
>>>> We forgot to mount shared storage (namely gluster volume), on which we
>>>> have config files, twice...
>>> If you're talking about the domain XML file, then you should never store
>>> them on a shared storage. All XML files in /etc/libvirt are supposed to
>>> be local to each host.
>> They are not stored in /etc/libvirt , but in other location, which is
>> suitable for sharing.
> I'm even more confused now. How could libvirt even know about such
> files? Unless you use transient domains, i.e., point libvirt to the
> right XML when starting the domain.

Yes, it transient, really, we use pacemaker's VirtualDomain
http://www.linux-ha.org/wiki/VirtualDomain_(resource_agent)

pacemaker creates domain and destroys it.

As I can see from sources migration looks like:
virsh ${VIRSH_OPTIONS} migrate --live $migrate_opts $DOMAIN_NAME 
$remoteuri $migrateuri &

Don't know which exact options it uses though.

Do we need xml on another host if domain is transient for live migration?

>
>> Unfortunately, my colleague left today  for 2 weeks vacations and I have
>> no access to these hosts,
>> so I will be able to look in logs or do some tests only in October.
>> So, I'll write there again after 2 weeks or so.
> Yeah, it would be nice if you could share the actual domain XML and the
> command you used for migrating it to the other host, too.
>

Don't sure I can do this, I know English a little bit  ( my colleague 
can't write ;-) ), but this  is his cluster, not my, so I prefer to wait 
2 weeks,
not try to request access....

Thank you!