[libvirt-users] Regarding persistence of VM's after live migration (virDomainMigrateToURI() problem)

[Cole Robinson]

On 05/02/2012 04:11 PM, Coding Geek wrote:
> 
> 
> On Wed, May 2, 2012 at 7:42 PM, Cole Robinson <crobinso at redhat.com
> <mailto:crobinso at redhat.com>> wrote:
> 
>     On 05/02/2012 04:52 AM, Coding Geek wrote:
>     >
>     >
>     > On Mon, Apr 30, 2012 at 9:07 PM, Cole Robinson <crobinso at redhat.com
>     <mailto:crobinso at redhat.com>
>     > <mailto:crobinso at redhat.com <mailto:crobinso at redhat.com>>> wrote:
>     >
>     >     On 04/25/2012 07:06 AM, Coding Geek wrote:
>     >     >
>     >     > Hello
>     >     > I am working with 3 host machines each running xen with shared NFS
>     >     storage. I
>     >     > am working on automatic load balancing if one host is over
>     utilized and
>     >     > another is under utilized by measuring the utilization from
>     xentop. I am
>     >     > facing a problem after migration of VM. I am setting the flags ( 1| 8|
>     >     16) in
>     >     > order to do live migration, persist VM on destination, undefine
>     host from
>     >     > source. After migration if I shut off the migrated VM on
>     destination host it
>     >     > does not persist. I am using the migrateToURI() API for migration.
>     >     >
>     >     > Please help how to make VM persist on destination.
>     >     >
>     >
>     >     There's a flag you can pass to the migration API,
>     VIR_MIGRATE_PERSIST_DEST.
>     >
>     >     - Cole
>     >
>     >
>     > Actually I am already using this flag VIR_MIGRATE_PERSIST_DEST but still
>     VM is
>     > not persisting on Destination. Do I need to change something while creating
>     > the VM?
>     >
> 
>     That flag might not be implemented to xen. But in that case it should
>     explicitly reject the flag. Please file a bug.
> 
>     But if you need a working solution, you can just do a lookupByName on the
>     remote host after migration, then define that guest to make it persistent.
> 
>     - Cole
> 
> 
> Ok. Before trying your solution one thing i want to ask. After migration I can
> do lookupByName which returns a domain pointer and then I can get the XML
> description of domain using getXMLDesc and then "can I still define the domain
> using defineXML because it returns a newly created domain's pointer?" and
> domain is already running in transient mode. I do not want to shut off the
> domain after migration.

Yes, you should be able to define on top of a running transient domain, and it
will become persistent.

- Cole