The recent custom endpoint addition allows us to directly point
certbot to the custom Pebble directory endpoint.
Thanks to that, we can ditch the Pebble patch we were using so far;
making this test maintenance easier.
Add a new option permitting to point certbot to an ACME Directory
Resource URI other than Let's Encrypt production/staging one.
In the meantime, we are deprecating the now useless Let's Encrypt
production flag.
* lm_sensors: add fancontrol module + nixos test
fancontrol is a small script that checks temperature sensors and adapts
fan speeds accordingly. It reads a text config file that can be
auto-generated by running the pwmconfig wizard on the live system.
Both options were introduced in systemd v243[1]. Those options can be
used to ensure that LinkLocalAddressing is only configured for a given
interface if DHCPv4 fails. To quote `systemd.network(5)`:
```
If "fallback" or "ipv4-fallback" is specified, then an IPv4
link-local address is configured only when DHCPv4 fails. If "fallback", an IPv6 link-local
address is always configured, and if "ipv4-fallback", the address is not configured. Note
that, the fallback mechanism works only when DHCPv4 client is enabled, that is, it requires
"DHCP=yes" or "DHCP=ipv4".
```
[1] 8bc17bb3f7
Default behavior is to continue executing the script even when one or
multiple steps fail. We want to abort early if any part of the
initialization fails to not run with a partially initialized state.
Default behavior also allows dereferencing non-existent variables,
potentially resulting in hard-to-find bugs.
While switching NixOS configurations with both
networking.useNetworkd = true;
virtualisation.virtualbox.host.enable;
You often end up waiting for systemd-networkd-wait-online.service.
This happens because the vboxnet0 device doesn't have a carrier until
virtualbox machines are started, so networkd gets stuck in
"Configuring":
⇒ networkctl list
IDX LINK TYPE OPERATIONAL SETUP
1 lo loopback carrier unmanaged
2 wlp2s0 wlan routable unmanaged
3 vboxnet0 ether no-carrier configuring
This updates the NixOS virtualbox host module to include a
RequiredForOnline=no statement in the generated 40-vboxnet0.network
file, so networkd doesn't consider it necessary for
systemd-networkd-wait-online.service to finish.
