This essentially backports
https://github.com/systemd/systemd/pull/27791. `systemd-networkd.service`
is sent the `SIGTERM` signal, but it is not required to be stopped
before `initrd-switch-root.target` is reached, despite the use of
`systemctl isolate initrd-switch-root.target`. This is because when
there is no ordering at all between two units, and a transaction stops
one and starts the other, the two operations can happen
simultaneously. This means the service could still be running when
`switch-root` actually occurs. Then, stage 2 systemd will see the
service still running and decide it doesn't need to add a start
operation for it to its initial transaction. Finally, the service
exits, but only after it's already too late. If, however, there is any
ordering at all between a stopping unit and a starting unit, then the
stop operation will be done first. This way, we ensure that the
service is properly exited before doing `switch-root`.
This is something to keep in mind going forward. There may be other
services that need this treatment. These `before` and `conflicts`
definitions are the correct way to ensure a unit is actually stopped
before you reach initrd-switch-root
The `B` in bridge should be capitalized.
It currently leads to an evuluation error:
```
error: attribute 'sectionbridgeVLAN' missing
at /nix/store/7wmrwj0sgwg1iivxk43lpkqjhji57mq7-source/nixos/modules/system/boot/networkd.nix:2386:56:
2385| example = { VLAN = "10-20"; };
2386| type = types.addCheck (types.attrsOf unitOption) check.network.sectionbridgeVLAN;
| ^
2387| description = lib.mdDoc ''
Did you mean sectionBridgeVLAN?
```
{manpage} already exapnds to a link but akkoma wants to link to
a specific setting. split the mention for clarity.
networkd just straight up duplicated what {manpage} generates anyway, so
that link can go away completely.
When no interfaces are managed by systemd-networkd, it will
unconditionally fail. This option allows it to be disabled in those
situations where it prevents system switches from succeeding.
Systemd 250:
> DHCPv4 client support in systemd-networkd learnt a new Label= option
> for configuring the address label to apply to configure IPv4
> addresses.
> The [IPv6AcceptRA] section of .network files gained support for a new
> UseMTU= setting that may be used to control whether to apply the
> announced MTU settings to the local interface.
> The [DHCPv4] section in .network file gained a new Use6RD= boolean
> setting to control whether the DHCPv4 client request and process the
> DHCP 6RD option.
> The [DHCPv6] section in .network file gained a new setting
> UseDelegatedPrefix= to control whether the delegated prefixes will be
> propagated to the downstream interfaces.
> The [IPv6AcceptRA] section of .network files now understands two new
> settings UseGateway=/UseRoutePrefix= for explicitly configuring
> whether to use the relevant fields from the IPv6 Router Advertisement
> records.
> The [RoutingPolicyRule] section of .network file gained a new
> SuppressInterfaceGroup= setting.
> The IgnoreCarrierLoss= setting in the [Network] section of .network
> files now allows a duration to be specified, controlling how long to
> wait before reacting to carrier loss.
Systemd 246:
> systemd-networkd's [DHCPv4] section gained a new setting UseGateway=
> which may be used to turn off use of the gateway information provided
> by the DHCP lease. A new FallbackLeaseLifetimeSec= setting may be
> used to configure how to process leases that lack a lifetime option.
> The IPv6Token= section in the [Network] section is deprecated, and
>> the [IPv6AcceptRA] section gained the Token= setting for its
>> replacement. The [IPv6Prefix] section also gained the Token= setting.
>> The Token= setting gained 'eui64' mode to explicitly configure an
>> address with the EUI64 algorithm based on the interface MAC address.
>> The 'prefixstable' mode can now optionally take a secret key. The
>> Token= setting in the [DHCPPrefixDelegation] section now supports all
>> algorithms supported by the same settings in the other sections.