2016-10-06 14:12 GMT+02:00 Barak Korren <bkorren@redhat.com>:

Something like the following (I'm assuming you have multiple hosts...):
1. Put host in to maintenance mode
2. Remove it from oVirt
3. Change host network settings
4. Re-attach host with new setting to oVirt
5. Migrate some VMs to the new host and fix their IP settings
6. Repeat for other hosts

Well, yes, I should add some routing logic before/during migration but it should work
Things to note:
- If you are using hosted-engine, it will further complicate things for you,
  I'm not sure if and how can one change the H.E. IP.

Yep, I'm with HE. Does anyone know if HE engine can be changed?
- If you are using an IP-based storage that is accessed via the same subnet,
  you need to ensure it is still accessible with the same name/IP from the
  new subnet.

Luckily storage is already on another vlan/network
If you are only making this change so you can run more VMs, you can
consider adding the new subnet as a new VLAN/physical LAN to the
existing hosts, and keep using old /24 subnet for ovirtmgmt. It is a
good idea to separate ovirtmgmt traffic from other traffic anyway...

Well I have a mix of physical hosts (excluding oVirt cluster obviously) and VM that are all on the same network right now, which is the ovirtmgmt network too, and I don't want to have special routing rules only for VMs.

Thanks for the tips!

Davide Ferrari
Senior Systems Engineer