GlobalIP not assigned in pod "init" phase

[davtex]

What happened:
I am experimenting with Submariner with Globalnet and Apache Cassandra -> NoSQL database that is not exactly cloud-friendly and relies heavily on P2P connections. For it to work correctly in multi-cluster environment, a parameter "broadcast_address" needs to be configured before startup -> Cassandra uses this value to "announce" on which IP it is available to the rest of the cluster. In non-Submariner setups this would be some sort of node/loadbalancer publicIP, in case of Submariner+Globalnet this would be GlobalIP. So theoretically I just need to configure GlobalIP in Cassandra config file before pod is started and I should be done.

Obvious choice for me here is to use initContainer to query endpointslices from kube-apiserver and add returned GlobalIP to Cassandra config. But here comes the issue -> even though pod already has PodIP assigned, Submariner waits for pod to be in "Running" phase to assign GlobalIP, meaning I am unable to query it since initContainers run during pod's "Init" phase -> before Running phase. FYI I am using "publishNotReadyAddresses: true" and service is headless -> lighthouse complains that GlobalIP has not yet been assigned.

What you expected to happen:
I expect GlobalIP to be assigned as soon as PodIP is available so it can be used for various tasks in initContainers.

How to reproduce it (as minimally and precisely as possible):
Create simple deployment with headless service and add initContainer -> GlobalIP won't be assigned until pod enters Running phase

Environment:

• OCP: 4.13.0-0.okd-2023-05-22-052007
• Submariner 0.15.2
• Cloud provider or hardware configuration: 2x vSphere clusters on-premise

[sridhargaddam]

CC: @tpantelis @vthapar

[tpantelis]

I think that's this b/c of this code and TODO in globalnet. We should honor the publishNotReadyAddresses annotation.