Ability to merge values (ip addresses) from multiple YAML files

[Lukas Märdian]

We want to assign multiple IP addresses to a given network interface, while some of the IP addresses are assigned/generated via cloud-init and others should be statically assigned.

Some have been using IP labels/aliases to implement this scenario:
https://bugs.launchpad.net/ubuntu/+source/nplan/+bug/1743200

Right now it is not possible to assign multiple addresses from different sources.

50-cloud-init.yaml:
version: 2
network:
  ethernets:
    eth0:
      addresses: [192.168.1.10/24] # auto-generated via cloud-init

60-static.yaml
network:
  ethernets:
    eth0:
      addresses: [192.168.10.10/24] # my static IP

This would result to:
eth0 having ONLY 192.168.10.10/24, as 60-static.yaml > 50-cloud-init.yaml

What we want to have is eth0 having 192.168.10.10/24 AND 192.168.0.10/24. Thus netplan needs the ability to additively merge the IP address values.

[Mészáros Máté Róbert (mrmeszaros)]

I have an issue, where my nameserver address gets eaten up by netplan merging the configs:

80-my-preferences.yaml:
network:
  version: 2
  renderer: networkd
  ethernets:
    ens160:
      nameservers:
        addresses: [10.10.10.10]

99-netcgf-vmware.yaml:
network:
  version: 2
  renderer: networkd
  ethernets:
    ens160:
      nameservers:
        search:
          - custom.intranet

And the second one fully overrides the nameservers section. I am not sure if it is intentional, or how could I override the automatic vmware config.