Created attachment 1788638 [details]
log

Description of problem:
When creating a veth pair with nmstate, the local and the peer ifaces are both managed(even though you haven't explicitly listed the peer iface under `interfaces` key). But when changing the peer's name, the old peer is removed, while the new one is unmanaged.

Version-Release number of selected component (if applicable):
nmstate-1.1.0-0.1.el8.noarch
nispor-1.1.0-1.el8.x86_64
NetworkManager-1.32.0-0.4.el8.x86_64

How reproducible:
100%

Steps to Reproduce:
# At creation, both veth0 and veth0_ep are managed
echo "interfaces:
- name: veth0
  type: veth
  state: up
  veth:
    peer: veth0_ep" | nmstatectl apply -

# At changing, newpeer is created, unmanged
echo "interfaces:
- name: veth0
  type: veth
  state: up
  veth:
    peer: newpeer" | nmstatectl apply -
nmcli con
nmcli dev

# This is exactly same with the 1st step, but veth0_ep is managed
echo "interfaces:
- name: veth0
  type: veth
  state: up
  veth:
    peer: veth0_ep" | nmstatectl apply -
nmcli con
nmcli dev

Actual results:
The old peer is removed while the new one is unmanaged

Expected results:
IMHO:
1. Once created, the peer is not allowed to change
or
2. The peer can be changed and make the new one controlled automatically
or
3. Like #bz1932247 , in anytime, user should explicitly list peer iface under `interfaces` key, otherwise it won't been managed. It's not convenient but gives a consistent experience.

Additional info: