Comment 0 for bug 1982857

cloud-init has two interactions with network backplanes

1. to write (or render) network configuration to the approapriate config files for the network system: systemd, netplan, network-manager, ENI, freebsd, netbsd, openbsd. This is done via cloudinit.net.renderers discovery[1]

2. optionally to bring up the network configuration via "network activation" for datasources discovered only in init boot stage after network is already up[2]

/etc/cloud/cloud.cfg allows system_info:network:renderers to configure overrides for default renderers, but not for activators. The two discovery/mechanisms don't know about each other and have separate logic to determine which is applicable on the given system.

Cloud-init should either:
 - Expose system_info: network: activators discovery priorty/order configuration in /etc/cloud/cloud.cfg*

 -- OR --

 - make activators aware of customized/overridden renderers priority from cloud.cfg and honor that priority order when discovering activators to use.

Without this feature, overridden network: renderer priority order to set network-manager as default renderer will result in cloud-init writing /etc/NetworkManager/system-connections/cloud-init-<NIC_NAME>.nmconnection but then trying to run `netplan apply` for a non-existent configuration on ubuntu Desktop installs.

References:
[1] network renderers discovery: https://github.com/canonical/cloud-init/blob/main/cloudinit/net/renderers.py#L67
[2] network activators discovery: