On Tue, 2021-03-30 at 18:30 +0800, Evan Zhao wrote:

Hi there,

I googled this question and found two major answers: 1. ssh to the compute node and use `virsh dumpxml` and `virsh undefine/define`, etc. 2. edit nova/virt/libvrit/config.py directly.

However, it's trivial to ssh to each node and do the modification, and I prefer not to touch the nova source code, is there any better ways to achieve this?

I expect to edit the namespace of a certain element and append an additional element <qemu:command> to the xml file.

Any information will be appreciated.

We purposefully don't allow this as it's not feasible to support. If you're using a vendor to provide your OpenStack packages, there's a good chance they won't allow you to do this either. Any modifications to the libvirt XML won't be persisted when you use any operation that results in the XML being rebuilt (cold migration, shelving, hard reboot, ...), while any chances to 'config.py' mean you have a fork on your hands that you're going to have to maintain for the life of the deployment. Neither are great situations to be in. You haven't described the _specific_ problem you're trying to resolve here. There's a possibility that nova may already have a feature to solve this problem. If not, there's a chance that your problem is a problem that other users are facing and therefore could warrant a new feature. If you raise your specific feature request here or IRC (#openstack-nova), we'll be more than happy to provide guidance. Cheers, Stephen