[RFE] Please add ManageForeignNextHops=no when it will be released in systemd 256

[akunszt]

Current situation

Please check the systemd/systemd#29034 ticket for the details.

Impact

We had to patch the systemd-networkd and rebuild the Flatcar images by ourselves to make our BGP routers work. For a time being it is fine to do this but in the long-run we prefer to use the official upstream images.

Ideal future situation

As systemd 256 adds support for ManageForeignNextHops like ManageForeignRoutes or ManageForeignRoutingPolicyRules please set it to no by default. This way the systemd-networkd won't interfere with any service which manages nexthops.

Implementation options

Add the following line to the [Network] section in /usr/lib/systemd/networkd.conf.d/10-disable-route-mgmt.conf.

ManageForeignNextHops=no

Additional information

This always can be set (or override) by the user. I am just asking to set the default the same way as you did with the routes and policies. Also please note that systemd 256 is not yet released and I have no information when that can hit Flatcar Linux. I created this ticket only as a "reminder".
If you think that the disabling that nexthop management is a bad default value then please close this, we can disable it in our configuration too.