[Users] VM migrations failing

[Martin Kletzander]

On 02/01/2013 09:29 PM, Dead Horse wrote:
> To test further I loaded up two more identical servers with EL 6.3 and the
> same package versions originally indicated. The difference here is that I
> did not turn these into ovirt nodes. EG: installing VDSM.
> 
> - All configurations were left at defaults on both servers
> - iptables and selinux disabled on both servers
> - verified full connectivty between both servers
> - setup ssh (/root/authorized keys) between the servers --> this turned out
> to be the key!
> 
> Then using syntax found here:
> http://libvirt.org/migration.html#flowpeer2peer
> EG: From the source server I issued the following:
>

So your client equals to the source server, that makes us sure that the
connection is made on the same network for p2p and non-p2p migration.

> virsh migrate --p2p sl63 qemu+ssh://192.168.1.2/system
> 

You're using ssh transport here, but isn't vdsm using tcp or tls?
According to the config file tcp transport is enabled with no
authentication whatsoever...

> It fails in exactly the same way as previously indicated when the
> destination server does not have an ssh rsa pub ID from the source system
> in it's /root/.ssh/authorized_keys file.
> However once the ssh rsa pub ID is in place on the destination system all
> is well and migrations work as expected.
> 

..., which would mean you need no ssh keys when migrating using tcp
transport instead.

Also during p2p migration the source libvirt daemon can't ask you for
the password, but when not using p2p the client is connecting to the
destination, thus being able to ask for the password and/or use
different ssh keys.

But it looks like none of this has anything to do with the problem as:

 1) as you found out, changing vdsm versions makes the problem go
away/appear and

 2) IIUC the first error was "function is not supported by the
connection driver: virDomainMigrateToURI2", but the second one was
"error: operation failed: Failed to connect to remote libvirt URI".

Since I tried finding out why the first error appeared, I probably
misunderstood somewhere in the middle of this thread and am useless
here.  However if I can help from the libvirt POV, I'll follow up this
thread and will see whether there's anything related.

Good luck,
Martin