We were not dealing with billing records for kubernetes clusters, as
we were in free early-access stage. But that will eventually change
and we will want to charge for kubernetes clusters.
This commit prepares for that day by incorporating logic to create and
delete billing records into cluster lifecycle.
Billing records are created right after the cluster is ready to use and
get finalized right after a customer decides to delete it.
All billing records are handled in KubernetesClusterNexus. Alternatively,
nodepool nexus could handle the nodepool billing, but that's not a big deal.
Currently, all resources are $0 but that will change once we go public-beta.
We still need to finalize LB management via CCM and start managing resources
in an internal project. After that, we can fully start billing for k8s.
We only have create and delete steps, and no update to billing records. When
update logic for a cluster is implemented (add node, change SKU, etc.), we would
need to remember implementing billing logic for these actions. Also, we should
remember to update billing records if/when we do manual scaling for a customer with
support ticket.
504effca55