[libvirt-users] concurrent migration of several domains rarely fails

Lentes, Bernd bernd.lentes at helmholtz-muenchen.de
Mon Dec 10 12:46:22 UTC 2018


Jim wrote:
>> 
>> What is meant by the "admin interface" ? virsh ?
> 
> virsh-admin, which you can use to change some admin settings of libvirtd, e.g.
> log_level. You are interested in the keepalive settings above those ones in
> libvirtd.conf, specifically
> 
> #keepalive_interval = 5
> #keepalive_count = 5
> 
>> What is meant by "client" in libvirtd.conf ? virsh ?
> 
> Yes, virsh is a client, as is virt-manager or any application connecting to
> libvirtd.
> 
>> Why do i have regular timeouts although my two hosts are very performant ? 128GB
>> RAM, 16 cores, 2 1GBit/s network adapter on each host in bonding.
>> During migration i don't see much load, although nearly no waiting for IO.
> 
> I'd think concurrently migrating 3 VMs on a 1G network might cause some
> congestion :-).
> 
>> Should i set admin_keepalive_interval to -1 ?
> 
> You should try 'keepalive_interval = -1'. You can also avoid sending keepalive
> messages from virsh with the '-k' option, e.g. 'virsh -k 0 migrate ...'.
> 
> If this doesn't help, are you in a position to test a newer libvirt, preferably
> master or the recent 4.10.0 release?

Hi Jim,

Unfortunately not.

I have some more questions, maybe you can help me a bit.
I found http://epic-alfa.kavli.tudelft.nl/share/doc/libvirt-devel-0.10.2/migration.html , which is
quite interesting.
When i migrate with virsh, i use:
virsh --connect=qemu:///system migrate --verbose --live  domain qemu+ssh://ha-idg-1/system

When pacemaker migrates, it creates this sequence:
virsh --connect=qemu:///system --quiet migrate --live  domain qemu+ssh://ha-idg-1/system
which is quite the same.
Do i understand the webpage correctly, is this a "Native migration, client to two libvirtd servers" ?

Furthermore the document says:
"To force migration over an alternate network interface the optional hypervisor specific URI must be provided".

I have both hosts also connected directly to each other with a bonding device using round-robin, and an internal ip (192.168.100.xx).
When i want to use this device, which is maybe a bit faster and more secure (directly connected), how do i have to specify that ?
virsh --connect=qemu:///system --quiet migrate --live  domain qemu+ssh://ha-idg-1/system tcp://192.168.100.xx
Does it have to be the ip from the source or the destination ? Does the source then use automatically use
also its device with 192.168.100.xx ?

Thanks.

Bernd

 

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