Nova doesn’t update Neutron about changing compute instance name

[Arkady Shtempler]

This is something that was raised on Neutron Designate DNS integration testing.
When VM server is created, its Nova name is used by Neutron as a hostname and then propagated to the DNS backends using Designate DNS, for example:
https://docs.openstack.org/neutron/yoga/admin/config-dns-int-ext-serv.html#use-case-1-floating-ips-are-published-with-associated-port-dns-attributes

Created VM is named “my_vm” and the “A” type Recordset propagated to the DNS backends is:
my-vm.example.org. | A | 198.51.100.4

Now, let’s say that the customer has decided to change VM’s name and that he would expect the previously created “A” type recordset to be change accordingly.
Unfortunately, such a change won’t affect either Neutron or Designate DNS, because Nova doesn’t update Neutron about changing VMs’ names.

[Uggla (rene-ribaud)]

Thanks for submitting this bug, but it is incomplete and can not be treated without the following information. Please add them to the ticket.

- steps to reproduce
- the version of Nova and the novaclient (or os-client)
- logs (on debug level)
- environment details depending on the bug
        libvirt/kvm versions, VMWare version, ...
        storage type (ceph, LVM, GPFS, ...)
        network type (nova-network or neutron)

[Arkady Shtempler (ashtempl)]

This bug is about missing Nova functionality, it's an enhancement needed to be added into the Nova code.

Steps to reproduce:
1) Deploy Devstack using attached local.conf file (This will enable Designate and Neutron with proper configuration to make it work)
2) Run "test_update_server_with_fip" test from this patch https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/855870
(not yet merged)

[Arkady Shtempler (ashtempl)]

Nova logged messages captured with: "sudo journalctl -f -u devstack@n* > nova.log"

[Lucas Kanashiro (lucaskanashiro)]

I added a task for sssd here to not miss this other bug report which is a dup of this one (#1989358). However, I am not sure how sssd is involved on this issue. Please, provide more information and detailed steps on how to reproduce the issue.

[Arkady Shtempler (ashtempl)]

Hi Lucas!

You are right, this issue was mistakenly tagged for "sssd (Ubuntu)" on creation and should be removed.

Thanks!

[sean mooney (sean-k-mooney)]

nova does not supprot updating the host name in neutron via updates to the hostname of the vm.
what is actually being updated in the tempest test is the display_name

the display name (after normalisation) is used as the initial value for the instance.hostname
instance.hostname is what is passed by nova to neutron and then read form neutron by designate.

in micoversion 2.90
hostname was added as an optional parameter to update on the server
https://docs.openstack.org/api-ref/compute/?expanded=update-server-detail#update-server

however neutron and desitnage integration was never part of that feature.

This is an RFE not a bug and the tempest tests in https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/855870
is incorrect. i have left review feedback explaining why.

if we want to add this functionality it would require a spec

once nova has set the initial value on a port it is then not updateable via nova.