Exception thrown when set-name equals an altname

[Jorge Merlino]

When a netplan configuration file contains a set-name for an interface and that name has been already set as an altname by systemd, netplan throws an exception and the interface ends up with no ip address.

Example:

Config file:
ens3:
    dhcp4: true
    match:
        macaddress: xx:xx:xx:xx:xx:xx
    set-name: enp0s3

Interface:
2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 52:54:00:1e:76:cc brd ff:ff:ff:ff:ff:ff
    altname enp0s3

Exception:
Traceback (most recent call last):
  File "/usr/sbin/netplan", line 23, in <module>
    netplan.main()
  File "/usr/share/netplan/netplan/cli/core.py", line 50, in main
    self.run_command()
  File "/usr/share/netplan/netplan/cli/utils.py", line 247, in run_command
    self.func()
  File "/usr/share/netplan/netplan/cli/commands/apply.py", line 61, in run
    self.run_command()
  File "/usr/share/netplan/netplan/cli/utils.py", line 247, in run_command
    self.func()
  File "/usr/share/netplan/netplan/cli/commands/apply.py", line 245, in command_apply
    subprocess.check_call(['ip', 'link', 'set',
  File "/usr/lib/python3.8/subprocess.py", line 364, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['ip', 'link', 'set', 'dev', 'ens3', 'name', 'enp0s3']' returned non-zero exit stat

[Jorge Merlino (jorge-merlino)]

Pull request for patch: https://github.com/canonical/netplan/pull/292