Comment 16 for bug 1807273

Verification-done for cosmic, using netplan.io 0.96-0ubuntu0.18.10.2:

As for the above test, I set up a new AWS instance (t2.micro); and applied the configuration (first trying to just set mtu: 1500; then using dhcp4-overrides: { use-mtu: false }).

ubuntu@ip-172-30-0-81:~$ dpkg -l netplan.io | grep ii
ii netplan.io 0.96-0ubuntu0.18.10.2 amd64 YAML network configuration abstraction for various backends
ubuntu@ip-172-30-0-81:~$ sudo netplan --debug apply
** (generate:2737): DEBUG: 16:39:55.688: Processing input file /etc/netplan/50-cloud-init.yaml..
** (generate:2737): DEBUG: 16:39:55.689: starting new processing pass
** (generate:2737): DEBUG: 16:39:55.689: Generating output files..
** (generate:2737): DEBUG: 16:39:55.689: NetworkManager: definition eth0 is not for us (backend 1)
(generate:2737): GLib-DEBUG: 16:39:55.689: posix_spawn avoided (fd close requested)
DEBUG:netplan generated networkd configuration changed, restarting networkd
DEBUG:no netplan generated NM configuration exists
DEBUG:eth0 not found in {}
DEBUG:Merged config:
network:
  bonds: {}
  bridges: {}
  ethernets:
    eth0:
      dhcp4: true
      dhcp4-overrides:
        use-mtu: false
      match:
        macaddress: 06:9d:85:76:e2:b2
      mtu: 1500
      set-name: eth0
  vlans: {}
  wifis: {}

DEBUG:Skipping non-physical interface: lo
DEBUG:device eth0 operstate is up, not changing
DEBUG:{}
DEBUG:netplan triggering .link rules for lo
DEBUG:netplan triggering .link rules for eth0
ubuntu@ip-172-30-0-81:~$ ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether 06:9d:85:76:e2:b2 brd ff:ff:ff:ff:ff:ff