The Adoption instructions should include guidance on how to configure the Podified Control Plane networking, and if needed reconfigure External Data Plane networking, so that combining the original data plane with the new control plane results in an operational cloud.

Significant part of the documentation about configuring networking will likely be common between IPv4 and IPv6, and should be addressed by the IPv4 epic OSPRH-882. The IPv6 epic is only about adding IPv6 specifics.

Specific areas of focus that may be made into stories:

• IP address management – what should the network config look like to avoid IPAM collisions between the data plane and the control plane.
• Adoption of data plane nodes' NIC configs - how to configure EDPM so that the NIC configs are preserved. We want to minimize risk, but depending on the IPAM there may be new routes to add, and so we may need to re-run os-net-config.
• Connecting the new control plane to original isolated networks – if there is anything more to advise on beyond the IPAM and NIC config issues.

The epic's deliverable is meant to be primarily documentation, but if we come across things that can also be tested in the test suite/CI, we should do so too.

Meetup brainstorming document is here for reference, but IPv6 specifics weren't discussed: https://docs.google.com/document/d/1ddw_RmD9w6nqOblVgNw-txQ5D1SgCaApNrYzZFTrI_8/edit

Watch out for:

• On OSP 17.1 it was possible to have a /64 subnet with multiple hosts inside it. For OSP 18 control plane, as a consequence of depending on OpenShift, it looks like we may need a /64 per host? There is a customer case about this problem which contains more information: https://access.redhat.com/support/cases/#/case/03414509
  • Related discussion on Slack https://redhat-internal.slack.com/archives/CQXJFGMK6/p1699617567988839