Add GitLab Kas architecture

For charts and GDK, we currently have it default disabled. No other
config is necessary.

doc/development/architecture.md

@@ -125,6 +125,8 @@ Praefect --> Gitaly
 NGINX --> GitLabWorkhorse
 NGINX -- TCP 8090 --> GitLabPages[GitLab Pages]
 NGINX --> Grafana[Grafana]
+NGINX -- TCP 8150 --> GitLabKas[GitLab Kubernetes Agent Server]
+GitLabKas --> Praefect
 Grafana -- TCP 9090 --> Prometheus[Prometheus]
 Prometheus -- TCP 80, 443 --> Puma
 RedisExporter[Redis Exporter] --> Redis
@@ -234,6 +236,7 @@ Table description links:
 | [GitLab Geo Node](#gitlab-geo)                        | Geographically distributed GitLab nodes |       ⚙        |       ⚙      |        ❌         |     ✅      |   ❌    |  ⚙  | EE Only |
 | [GitLab Managed Apps](#gitlab-managed-apps)           | Deploy Helm, Ingress, Cert-Manager, Prometheus, GitLab Runner, JupyterHub, or Knative to a cluster |  ⤓  |  ⤓  |      ⤓       |     ⤓      |   ⤓    |  ⤓  | CE & EE |
 | [GitLab Pages](#gitlab-pages)                         | Hosts static websites                                                |       ⚙        |      ❌       |        ❌         |     ✅      |   ⚙    |  ⚙  | CE & EE |
+| [GitLab Kubernetes Agent](#gitlab-kubernetes-agent)   | Integrate Kubernetes clusters in a cloud-native way                  |       ❌       |      ⚙        |        ❌         |     ❌      |   ⤓    |  ⚙   | EE Only |
 | [GitLab self-monitoring: Alertmanager](#alertmanager) | Deduplicates, groups, and routes alerts from Prometheus              |       ⚙        |      ✅       |        ⚙         |     ✅      |   ❌    |  ❌  | CE & EE |
 | [GitLab self-monitoring: Grafana](#grafana)           | Metrics dashboard                                                    |       ✅        |      ⚙       |        ⤓         |     ✅      |   ❌    |  ❌  | CE & EE |
 | [GitLab self-monitoring: Jaeger](#jaeger)             | View traces generated by the GitLab instance                         |       ❌        |      ⚙       |        ❌         |     ❌      |   ⤓    |  ⚙  | CE & EE |
@@ -380,6 +383,18 @@ repository updates to secondary nodes.
 
 GitLab Exporter is a process designed in house that allows us to export metrics about GitLab application internals to Prometheus. You can read more [in the project's README](https://gitlab.com/gitlab-org/gitlab-exporter).
 
+#### GitLab Kubernetes Agent
+
+- [Project page](https://gitlab.com/gitlab-org/cluster-integration/gitlab-agent)
+- Configuration:
+  - [Charts](https://docs.gitlab.com/charts/charts/gitlab/kas/index.html)
+
+[GitLab Kubernetes Agent](../user/clusters/agent/index.md) is an active in-cluster
+component for solving GitLab and Kubernetes integration tasks in a secure and
+cloud-native way.
+
+You can use it to sync deployments onto your Kubernetes cluster.
+
 #### GitLab Pages
 
 - Configuration: