[Openstack] Upgrade nova-network without downtime?
abogott at wikimedia.org
Mon Aug 3 14:17:05 UTC 2015
On 7/28/15 1:32 PM, Andrew Bogott wrote:
> I'm running Icehouse with the 'legacy' nova-network service and a
> single network node.
> Everything in my cluster is running Ubuntu Trusty and ready for an
> upgrade to Juno, except for my network node, which is still running
It turns out that I now need to do rolling restarts of my compute nodes
for an unrelated issue (see: "kvm suspend vs. the kernel") so I have a
bit more leeway with this problem. After a bit of reading I'm convinced
that while I'm messing with things it's probably a good idea to switch
to multi_host anyway. So, I propose the following steps:
1) Install nova-network on all compute nodes
2) nova-network delete (current network setting)
3) nova-network create (same network settings as in step 2 except with
4) restart nova-network on all compute nodes
My supposition is that after doing that, old instances will continue to
use my old, standalone network node (as specified in their cached dhcp
settings) until they are restarted at which point they'll switch over to
using their local compute host as a router thanks to the multi_host setting.
Can anyone confirm that this is a sensible plan, or warn me off of it?
The main danger I see is that at that after step 2, nova-compute
probably can't be safely restarted on my original compute node -- that's
definitely a bit fragile :(
More information about the Openstack