Hello, thank you so much for your contribution. I think it's an important addition to Netplan!

The current version of networkd supports many other options for [IPv6AcceptRA] but we can extend it later. We usually target the recent versions of the backends we support.

I left a few suggestions in your PR I'd like you to consider.

Thank you :)

Thank you very much for your contribution to Netplan! You touched quite a few modules to get this change landed. Kudos for working through all of them!

Thanks for working through Danilo's recommendations already! I left plenty of additional inline comments. It's mostly small stuff that should be relatively easy to fix.

Regarding the YAML schema addition, I mostly agree with your proposal. It matches networkd's naming and I couldn't find corresponding NetworkManager settings. But I think should consider renaming the new setting to ra-overrides staying consistent with the accept-ra setting that it relates to (without the "ipv6" prefix). Furthermore, I think we should rename route-table to just table, as it is used in other places in Netplan's configuration. E.g.:

  accept-ra: true
  ra-overrides:
    use-routes: false
    use-domains: false
    table: 127

Alternatively, I was also pondering about implicitly setting accept-ra: true when using a mapping, as those settings only make sense in combination. But that would not be consistent with the existing dhcp4/6-overrides stanzas:

  accept-ra: # implicitly set to "true", as a mapping is defined below
    use-dns: false
    use-domains: false

I'd like to get an opinion from our architect about that.
@vorlonofportland What do you think about this new schema?

Thank you for addressing all of my remarks!

LGTM, and kudos, this is a really nice PR!

I left one tiny inline-comment, also we should probably address this comment from Steve before merging:

I believe that the default for use-domains (and current behavior) is False? this should be included in the documentation

I might be able to do that quickly myself..