Dual-stack support on vSphere

[christianang]

Describe the feature request

As an admin/operator:

I would like to be able to configure/deploy Kubernetes clusters that support dual stack networking (IPv4/IPv6)
Because:

The routing of workload traffic, both ingress and egress, may be conditional on the type of workload, and thus may also select a specific address family (IPv4 or IPv6) based on the workload type. Therefore we want to configure/deploy Kubernetes clusters that support dual-stack traffic, both ingress and egress.

Proposal

An admin/operator can specify ipv4,ipv6 or ipv6,ipv4 for the TKG_IP_FAMILY field. The first IP family in the list becomes the "primary" ip family of the cluster. This matters in various ways e.g SingleStack Services, default podIP, upgrading from a single stack to dual-stack, control plane endpoint VIP.
If specified, the SERVICE_CIDR and CLUSTER_CIDR must be a list of two CIDRs and must match the order of TKG_IP_FAMILY.
If SERVICE_CIDR or CLUSTER_CIDR is not specified it should default to the default ipv4 and ipv6 CIDRs in the correct order.

Describe alternatives you've considered

n/a

Affected product area (please put an X in all that apply)

• APIs
• Addons
• CLI
• Docs
• Installation
• Plugin
• Security
• Test and Release
• User Experience

Additional context

cc @mcwumbly @tylerschultz @adobley

[christianang]

For future reference, we made a PR to community edition to add some additional validation that we will need for #617 to work. However, I wouldn't consider it blocking, we can make a follow up PR to bump the vendir directory for vsphere-cpi once the community edition PR is merged.

[christianang]

All known items that we think need to be done for dual-stack have been done and dual-stack support has been added. Closing issue.