Add hostname annotation to set loadbalancer ingress hostname

[hrak]

This fixes problems with kube-proxy in ipvs mode considering the loadbalancer IP as local to the node (causing loadbalanced services to be unreachable).

See kubernetes/kubernetes#66607

This can also be used to access PROXY proto service from the inside.

[vishesh92]

clgtm

[weizhouapache]

code lgtm

@hrak
can you describe how to use/test it ?

[vishesh92]

Did some manual testing. After this change, I have verified that the service created has external IP equal to hostname set in service.beta.kubernetes.io/cloudstack-load-balancer-hostname. And the same hostname is also set in the status of the service.

[weizhouapache]

Did some manual testing. After this change, I have verified that the service created has external IP equal to hostname set in service.beta.kubernetes.io/cloudstack-load-balancer-hostname. And the same hostname is also set in the status of the service.

cool, thanks @vishesh92
can you test ipvs mode if the issue can be reproduced and fixed by this change ?

[vishesh92]

@weizhouapache I am not able to reproduce the issue, but I can verify the functionality is working as expected. For why hostname is required as part of the loadbalancerStatus, check: https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.27/#loadbalanceringress-v1-core