subiquity->cloud-init generates netplan yaml telling user not to edit it

[Steve Langasek]

As seen in <https://askubuntu.com/questions/1222752/how-to-get-out-of-a-netplan-rabbit-hole>, users who install with subiquity end up with a /etc/cloud/cloud.cfg.d/50-curtin-networking.cfg that persists on the target system, plus an /etc/netplan/50-cloud-init.yaml that tells users not to edit it without taking steps to disable cloud-init.

I don't think this is what we want. I think a subiquity install should unambiguously treat cloud-init as a one-shot at installation, and leave the user afterwards with config files that can be directly edited without fear of cloud-init interfering; and the yaml files generated by cloud-init on subiquity installs should therefore also not include this scary language:

# This file is generated from information provided by the datasource. Changes
# to it will not persist across an instance reboot. To disable cloud-init's
# network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}

But we need to figure out how to fix this between subiquity and cloud-init.

[Ryan Harper (raharper)]

I thought at some point subiquity used to write /etc/netplan/ files directly into the target;
and I think it'd make sense to emit a cloud-init config to disable cloud-init's control over networking as well.

[Michael Hudson-Doyle (mwhudson)]

On Wed, 1 Apr 2020 at 11:31, Ryan Harper <email address hidden> wrote:

> I thought at some point subiquity used to write /etc/netplan/ files
> directly into the target;
> and I think it'd make sense to emit a cloud-init config to disable
> cloud-init's control over networking as well.
>

It did, before cloud-init understood v2 network config I think. We could
certainly go back to that.

[Michael Hudson-Doyle (mwhudson)]

https://github.com/CanonicalLtd/subiquity/pull/670

[Paride Legovini (paride)]

I'm not marking this Fix Released for subiquity as the change has not been released in all the subiquity channels yet.

[James Falcon (falcojr)]

Tracked in Github Issues as https://github.com/canonical/cloud-init/issues/3639