"netplan apply" does not apply changes to netmask when CIDR notation modified on static IP

[Suzanne Palmer]

So, somebody who hadn't had enough coffee one morning typoed the CIDR notation in /etc/netplan/01-netcfg.yaml on their server, resulting in the wrong netmask for the static IP. I corrected the CIDR notation, but "netplan apply" would not pick up the new info and update the netmask. Tested across four servers running 18.04 and same behavior occurred; required a reboot to get them to pick up the changed netmask info.

Thanks!
-Suzanne

[Lukas Märdian (slyon)]

I cannot reproduce this with Netplan 0.99 on Bionic. Please re-open if this is still an issue for you.

root@bb:~# cat /etc/netplan/50-cloud-init.yaml
network:
    version: 2
    ethernets:
        eth0:
            dhcp4: true
            addresses: [10.10.10.23/23]
root@bb:~# netplan apply
root@bb:~# ip a show dev eth0
88: eth0@if89: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:16:3e:bd:da:7d brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 10.10.10.23/23 brd 10.10.11.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet 10.238.94.182/24 brd 10.238.94.255 scope global dynamic eth0
       valid_lft 3591sec preferred_lft 3591sec
    inet6 fd42:7213:f20e:bd74:216:3eff:febd:da7d/64 scope global mngtmpaddr noprefixroute
       valid_lft forever preferred_lft forever
    inet6 fe80::216:3eff:febd:da7d/64 scope link
       valid_lft forever preferred_lft forever

root@bb:~# vim /etc/netplan/50-cloud-init.yaml
root@bb:~# cat /etc/netplan/50-cloud-init.yaml
network:
    version: 2
    ethernets:
        eth0:
            dhcp4: true
            addresses: [10.10.10.23/24]
root@bb:~# netplan apply
root@bb:~# ip a show dev eth0
88: eth0@if89: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:16:3e:bd:da:7d brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 10.10.10.23/24 brd 10.10.10.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet 10.238.94.182/24 brd 10.238.94.255 scope global dynamic eth0
       valid_lft 3595sec preferred_lft 3595sec
    inet6 fd42:7213:f20e:bd74:216:3eff:febd:da7d/64 scope global mngtmpaddr noprefixroute
       valid_lft forever preferred_lft forever
    inet6 fe80::216:3eff:febd:da7d/64 scope link
       valid_lft forever preferred_lft forever