libvirt users - Jan 2015 - Libvirt to return the ip address instead of the hostname during migration

Hi all,

We are working on nova live-migration using Ceph and trying to work around
the problem where vm migration fails if name resolution is not enabled in a
cluster. See the link,

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization_Host_Configuration_and_Guest_Installation_Guide/App_Migration_Address.html

We have managed to work around this by setting the flag to include
“VIR_MIGRATE_TUNNELLED”.
However, it is noticebaly slower than non tunnelled.

We were hoping that setting the listen_addr would get libvirt to return the
listen_addr rather than the hostname but virGetHostname in
libvirt/src/util/virutil.c doesn’t have access to the config structure.

I was wondering if libvirt can be patched in a way to return the ip address
of the destination instead of the hostname during migration?

Regards,
Yagmur Akbulut

The tunneled mode for migration is built on GNU TLS and is rather slow. 
Interest moved to NBD (which currently doesn't support any encryption) 
which is (quite a bit) faster, and the tunneled migration function gets 
no love.

Likely that any encryption added to NBD will have the same performance 
degradation.

On 1/9/15 3:59 PM, Yagmur Akbulut wrote:
> We are working on nova live-migration using Ceph and trying to work
> around the problem where vm migration fails if name resolution is not
> enabled in a cluster. See the link,
>
>
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization_Host_Configuration_and_Guest_Installation_Guide/App_Migration_Address.html
>
> We have managed to work around this by setting the flag to include
> “VIR_MIGRATE_TUNNELLED”.
> However, it is noticebaly slower than non tunnelled.
>
> We were hoping that setting the listen_addr would get libvirt to return
> the listen_addr rather than the hostname but virGetHostname in
> libvirt/src/util/virutil.c doesn’t have access to the config structure.
>
> I was wondering if libvirt can be patched in a way to return the ip
> address of the destination instead of the hostname during migration?

-- 
Gary R Hook
Senior Kernel Engineer
NIMBOXX, Inc