DNS across hybrid environments - with Cloud DNS, Private Service Connect and VPC Service Controls

## Requirements: Investigate Cloud DNS and On-prem DNS scenarios for implementing DNS across hybrid environment

## Slides
37 of shared deck https://docs.google.com/presentation/d/1Ztqn7G2rWFlssVwC7r5Xl-WFSFCbVo6MoHJffrXScmw/edit#slide=id.g228c00ae937_0_0
Reference all DNS sections of networking design patterns deck starting with 20, 27
https://docs.google.com/presentation/d/13sjT2tJ4yLIYGRREE3wBrylB1OvcEMpKdquVuJB_nX4/edit?resourcekey=0-N3DruQaiutFvZ98HTT7-vQ#slide=id.g1154b3b950f_2_3152

## Procedures
- https://cloud.google.com/dns/docs/policies#create-in

## Implementation
- on prem DNS servers are authoritative for on prem zones
- cloud DNS is authoritative for GCP zones
- DNS queries from GCP to on-prem use 35.199.192.0/19
### Manual
- simulate on-prem...(other CSP or eBGP enabled home router)
- create dns-host-ol project - host project enabled on shared vpc creation
- enable apis
```
dns.googleapis.com
```
- set permissions
Required 'compute.organizations.enableXpnHost' permission for 'projects/dns-host-ol' - https://gcp.permissions.cloud/predefinedroles/compute.xpnAdmin
- create custom vpc (for reuse as shared vpc)
```
gcloud compute networks create host --project=dns-host-ol --description=hody --subnet-mode=custom --mtu=1460 --bgp-routing-mode=regional
gcloud compute networks subnets create host-sn --project=dns-host-ol --description=host-sn --range=10.0.2.0/24 --stack-type=IPV4_ONLY --network=host --region=northamerica-northeast1 --enable-private-ip-google-access
```
- create host shared-vpc (custom networks, dns api enabled)
-
- create dns private zones in host project
```
gcloud dns --project=dns-host-ol managed-zones create private --description="" --dns-name="private.obrienlabs.dev." --visibility="private" --networks="host"
```
- enable compute api
- create shared vpc
- create service project dns-sp-ol
- create dns egress proxy in shared vpc
- create inbound server policy in Cloud DNS for on prem
- create forwarding zone in Cloud DNS for on prem
-
- On Prem DNS
-
-

### Automated