Update documentation for network-config-format-v2

[ggiesen]

Routes are a per-interface property, not a global network property

Proposed Commit Message

Update documentation for network-config-format-v2 to reflect the fact that
routes are a per-interface property, not a global network property

Additional Context

Test setup consists of the following:
CentOS 8.2.2004
cloud-init v.19.4
cloud-init-vmware-guestinfo v1.4.1

Test Steps

The following config (per the example in the documentation) does not install a static route:

instance-id: host
local-hostname: host
network:
  version: 2
  ethernets:
    ens192:
      dhcp4: false
      addresses:
      - 192.0.2.10/28
      gateway4: 192.0.2.1
      nameservers:
        addresses:
        - 192.0.2.5
        search:
        - example.com
    ens224:
      dhcp4: false
      addresses:
      - 192.0.2.26/28
  routes:
  - to: 192.0.2.128/25
    via: 192.0.2.17
	metric: 1

The following metadata config does install the static route:

instance-id: host
local-hostname: host
network:
  version: 2
  ethernets:
    ens192:
      dhcp4: false
      addresses:
      - 192.0.2.10/28
      gateway4: 192.0.2.1
      nameservers:
        addresses:
        - 192.0.2.5
        search:
        - example.com
    ens224:
      dhcp4: false
      addresses:
      - 192.0.2.26/28
      routes:
      - to: 192.0.2.128/25
        via: 192.0.2.17
		metric: 1

Checklist:

• My code follows the process laid out in the documentation
• I have updated or added any unit tests accordingly
• I have updated or added any documentation accordingly

[raharper]

Thanks for catching that. Indeed routes are per device, not a top-level key in v2.

Since you here, it may be useful to update the docs on where to go for netplan info:

https://netplan.io

This has examples and a FAQ, we could link to that instead of the launchpad.net/netplan URL at the bottom of this file.

Thoughts?

[ggiesen]

I agree and I've updated the netplan URL to https://netplan.io

[OddBloke]

Thanks!