[Openstack] Live migration with mult_host - only ugly approach?

이준원 (Joonwon Lee) joonwon7.lee at samsung.com
Mon Dec 26 09:23:21 UTC 2011

Dear all.

We want to use Kei's live migration feature while adopting Vish’s
multi_host network configuration, but there are problems as noted below by

Is there any way to change the gateway of a VM instance?
(i.e. is it possible to force a VM instance to request DHCP server again?)

As I found no clue on this, it may be better to implement storing the
history of live migration in DB. And we should keep the iptables rules and
DHCP entries(in nova-br100.conf) for VM instances migrated in two or more
hosts. I'm going to take this *ugly* approach without a good idea.

The common gateway cannot be set for us because the network of
VMs(10.x.x.x) is different from the network of external
switches/routers(public IPs).
Also the minimum DHCP expiration time is 120 seconds according to the man
page. Two minutes are too long. Even worse, a VM instance won't change the
gateway set by DHCP until rebooting with my test.

Please help me finding a better approach, if any.
Thanks in advance.

Joonwon Lee

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