docs: add dns setup (#767)

## Description
Adding documentation on the DNS assumptions in UDS Core and added
example for deploying in a non-dev environment.

## Related Issue

Fixes #730

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [x] Other (security config, docs update, etc)

## Checklist before merging

- [ ] Test, docs, adr added or updated as needed
- [ ] [Contributor
Guide](https://github.com/defenseunicorns/uds-template-capability/blob/main/CONTRIBUTING.md)
followed

---------

Co-authored-by: Micah Nagel <micah.nagel@defenseunicorns.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Rob Ferguson <rjferguson21@gmail.com>
Co-authored-by: Chance <139784371+UnicornChance@users.noreply.github.com>
Co-authored-by: UncleGedd <42304551+UncleGedd@users.noreply.github.com>
Co-authored-by: Nigel Foucha <73838612+nfoucha@users.noreply.github.com>
Co-authored-by: Micah Nagel <micah.nagel@gmail.com>

bundles/k3d-slim-dev/README.md

@@ -12,7 +12,7 @@ The k3d uds-dev-stack provides:
 - [Minio](https://min.io/) - In-cluster S3 Object Storage (See below for more details)
 - [Local Path Provisioner](https://github.com/rancher/local-path-provisioner/) - Local Storage with RWX
 - [MetalLB](https://metallb.universe.tf/) - Provides type: LoadBalancer for cluster resources and Istio Gateways
-- [HAProxy](https://www.haproxy.org/) - Utilizes k3d host port mapping to bind ports 80 and 443, facilitating local FQDN-based routing through ACLs to MetalLB load balancer backends for Istio Gateways serving *.uds.dev, keycloak.uds.dev, and *.admin.uds.dev.
+- [NGINX](https://nginx.org/) - Utilizes k3d host port mapping to bind ports 80 and 443, facilitating local FQDN-based routing through ACLs to MetalLB load balancer backends for Istio Gateways serving *.uds.dev, keycloak.uds.dev, and *.admin.uds.dev.
 
 ## Available Overrides
 ### Package: uds-k3d

bundles/k3d-standard/README.md

@@ -6,7 +6,7 @@ This bundle is used for demonstration, development, and testing of UDS Core. In
 - [Minio](<https://min.io/>) - In-cluster S3 Object Storage (See below for more details)
 - [Local Path Provisioner](<https://github.com/rancher/local-path-provisioner>) - Storage Provider with RWX configured
 - [MetalLB](https://metallb.universe.tf/) - Provides type: LoadBalancer for cluster resources and Istio Gateways
-- [HAProxy](https://www.haproxy.org/) - Utilizes k3d host port mapping to bind ports 80 and 443, facilitating local FQDN-based routing through ACLs to MetalLB load balancer backends for Istio Gateways serving *.uds.dev, keycloak.uds.dev, and *.admin.uds.dev.
+- [NGINX](https://nginx.org/) - Utilizes k3d host port mapping to bind ports 80 and 443, facilitating local FQDN-based routing through ACLs to MetalLB load balancer backends for Istio Gateways serving *.uds.dev, keycloak.uds.dev, and *.admin.uds.dev.
 
 ## Available Overrides
 ### Package: uds-k3d

docs/deployment/dns.md

@@ -0,0 +1,74 @@
+---
+title: DNS Configuration
+type: docs
+weight: 2
+---
+
+UDS Core deploys two Gateways by default - a Tenant Gateway for end-user applications and an Admin Gateway for administrative applications. You can read more about Istio configuration in UDS Core [here](https://uds.defenseunicorns.com/core/configuration/istio/ingress/). This section covers how to configure DNS for these Gateways.
+
+### Domain Configuration
+Each Gateway is associated to a wildcard DNS entry that is derived from the `DOMAIN` [variable](https://github.com/defenseunicorns/uds-core/blob/e624d73f79bd6739b6808fbdbf5ca75ebb7c1d3c/src/istio/zarf.yaml#L8) in the UDS Core Istio package. When deploying UDS Core, you can expect two Gateways to be created that match the following domain names:
+- `*.<DOMAIN>` / Tenant Gateway
+- `*.admin.<DOMAIN>` / Admin Gateway
+
+{{% alert-note %}}
+The default value for `DOMAIN` is `uds.dev`, which is intended for development purposes only. For non-development purposes, you should override this value by specifying a value for `domain` in your `uds-config.yaml`. You can find instructions on how to do so [here](https://uds.defenseunicorns.com/core/configuration/istio/ingress/#configure-domain-name-and-tls-for-istio-gateways). 
+{{% /alert-note %}}
+
+### Bundle Configuration
+{{% alert-note %}}
+UDS Core does not include any cloud provider specific configuration by default. Additional overrides are required to deploy UDS Core on a given provider. This section will refer to AWS, but values can be substituted as needed for other providers.
+{{% /alert-note %}}
+
+The Admin and Tenant Gateways will be each be bound to an external Load Balancer that is exposed on TCP ports 80 and 443 by default. The Admin Gateway should be configured to use an internal facing Load Balancer and the Tenant Gateway should be configured to use an external facing Load Balancer. Below is an example of overrides that would accomplish this:
+```yaml
+kind: UDSBundle
+metadata:
+  name: core-with-lb-config
+  description: A UDS example bundle for deploying UDS Core with external Load Balancer configuration
+  version: "0.0.1"
+
+packages:
+  - name: core
+    repository: oci://ghcr.io/defenseunicorns/packages/uds/core
+    ref: 0.27.0-upstream
+
+overrides:
+ istio-admin-gateway:
+   gateway:
+     values:
+      - path: service.annotations.service\.beta\.kubernetes\.io/aws-load-balancer-type
+        value: "external"
+      - path: service.annotations.service\.beta\.kubernetes\.io/aws-load-balancer-scheme
+        value: "internal"
+      - path: service.annotations.service\.beta\.kubernetes\.io/aws-load-balancer-attributes
+        value: "load_balancing.cross_zone.enabled=true"
+  istio-tenant-gateway:
+    gateway:
+      values:
+      - path: service.annotations.service\.beta\.kubernetes\.io/aws-load-balancer-type
+        value: "external"
+      - path: service.annotations.service\.beta\.kubernetes\.io/aws-load-balancer-scheme
+        value: "internet-facing"
+      - path: service.annotations.service\.beta\.kubernetes\.io/aws-load-balancer-attributes
+        value: "load_balancing.cross_zone.enabled=true"        
+```
+
+### Istio Gateways
+Once UDS Core is deployed, there will be Istio Gateway resources in your cluster. You can find each Gateway in a dedicated namespace:
+```cli
+$ kubectl get gateway -A
+NAMESPACE              NAME             AGE
+istio-admin-gateway    admin-gateway    1h
+istio-tenant-gateway   tenant-gateway   1h
+```
+
+Each Gateway will have a Kubernetes Service of type Load Balancer:
+```cli
+$ kubectl get svc -A | grep LoadBalancer
+NAMESPACE                   NAME                                             TYPE           CLUSTER-IP      EXTERNAL-IP                                        PORT(S)                                     AGE
+istio-admin-gateway         admin-ingressgateway                             LoadBalancer   10.43.82.84     k8s-istioadm-admin...elb.us-east-1.amazonaws.com   15021:30842/TCP,80:31304/TCP,443:31518/TCP  1h
+istio-tenant-gateway        tenant-ingressgateway                            LoadBalancer   10.43.47.182    k8s-istioten-tenant...elb.us-east-1.amazonaws.com  15021:31222/TCP,80:30456/TCP,443:32508/TCP  1h
+```
+
+From here, you can register your domain and/or create DNS records for your environment that point to the appropriate Gateways/Load Balancers. Refer to your DNS provider's documentation.