Allow to register all pods and their associated PTR record

[foyerunix]

Hello,

We have deployed multiples Kubernetes clusters on-premise. Our cluster use Cilium CNI with SNAT disabled. This mean the pods traffic will exit the cluster with their pod IP and not with the node IP (the pod IPs are then correctly routed back to Kubernetes).

This is useful for us as a SRE team as we can track easily which pod is making which connection.
The drawback is that we still have to check on Kubernetes the pod which is associated with a particular IP.

As external-dns already implemented the pod source and the creation of PTR record, I thought it would be easy to register the pods PTR record in the DNS. But the pod source seem to has been made for a very precise use case relating to kops.

I therefore implemented two new options for our use case:

• --ignore-non-host-network-pods
• --pod-source-domain

The first let us create DNS records for pods even if they aren't running with host networking enabled.
The second allow us to build a pod FQDN with a default domain even without annotations.

I'm hesitating to combine the two as only one option ("--all-pods-domain" ?) that would then bypass the original intended use case for the pod source. I worry that the combination of the kops use case and mine in the same configuration will lead to an absurd behavior. But what if someone have a legitimate use for this ?

Please can you give me your opinion on the current implementation or if you would want to refactor it in another way.

Best Regards.

[linux-foundation-easycla]

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