Add weighted address strategy for multi-key listeners (#2394)

[gabordozsa]

Add weighted address strategy for multi-key listeners

Fixes #2394

[fgiorgetti]

It is working great on both kubernetes with system sites. Nice job @gabordozsa.

One thing that we need to consider, is whether the strategy field should be immutable or not. If we allow it to change, we should cleanup the status.strategy field and update it with the new strategy.

[gabordozsa]

One thing that we need to consider, is whether the strategy field should be immutable or not. If we allow it to change, we should cleanup the status.strategy field and update it with the new strategy.

@fgiorgetti I think the strategy field should be immutable for now. The router does not allow updating the strategy so, the control plane should delete and re-create the multi-key listener if strategy changes. That would terminate existing TCP connections. If strategy update is required, we may add it in a follow up change including the router support for it.

[fgiorgetti]

One thing that we need to consider, is whether the strategy field should be immutable or not. If we allow it to change, we should cleanup the status.strategy field and update it with the new strategy.

@fgiorgetti I think the strategy field should be immutable for now. The router does not allow updating the strategy so, the control plane should delete and re-create the multi-key listener if strategy changes. That would terminate existing TCP connections. If strategy update is required, we may add it in a follow up change including the router support for it.

Agreed. The CRD validation could be enhanced to guarantee that the field is immutable.

[pwright]

Help me understand immutable in this context.
If i create a CR named 'A' with strategy 'priority', I can not change the strategy without first deleting 'A' resource. Can i then recreate 'A' with strategy weighted?

[fgiorgetti]

Help me understand immutable in this context. If i create a CR named 'A' with strategy 'priority', I can not change the strategy without first deleting 'A' resource. Can i then recreate 'A' with strategy weighted?

Correct.

[pwright]

lgtm

[gabordozsa]

Agreed. The CRD validation could be enhanced to guarantee that the field is immutable.

@fgiorgetti I added the extra CRD validation following your guidance. It covers kube platform. System platform validation will be covered in a follow up change after dynamic reload work is completed in issue #2411.

[fgiorgetti]

LGTM. Thank you.