Add deprecation notice to cert-based clusters docs

- Deprecate all features built on top of the K8s integration
via cluster certificates
- Remove CI envs changes
  I'll ship a separate MR for this doc
- Link to Prometheus manual integration
- Remove h1 anchor
- Update link to "manually enable" anchor
- Add deprecation to project-level clusters doc
- Address PM review

doc/administration/integration/terminal.md

@@ -4,7 +4,12 @@ group: Integrations
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
-# Web terminals **(FREE)**
+# Web terminals (DEPRECATED) **(FREE)**
+
+> [Deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
+
+WARNING:
+This feature was [deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
 
 With the introduction of the [Kubernetes integration](../../user/infrastructure/clusters/index.md),
 GitLab can store and use credentials for a Kubernetes cluster.

doc/api/group_clusters.md

@@ -4,9 +4,13 @@ group: Configure
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
-# Group clusters API **(FREE)**
+# Group clusters API (certificate-based) (DEPRECATED) **(FREE)**
 
-> [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/30213) in GitLab 12.1.
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/30213) in GitLab 12.1.
+> - [Deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
+
+WARNING:
+This feature was [deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
 
 Similarly to [project-level](../user/project/clusters/index.md) and
 [instance-level](../user/instance/clusters/index.md) Kubernetes clusters,

doc/api/instance_clusters.md

@@ -4,9 +4,13 @@ group: Configure
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
-# Instance clusters API **(FREE SELF)**
+# Instance clusters API (certificate-based) (DEPRECATED) **(FREE SELF)**
 
-> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/36001) in GitLab 13.2.
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/36001) in GitLab 13.2.
+> - [Deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
+
+WARNING:
+This feature was [deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
 
 With [instance-level Kubernetes clusters](../user/instance/clusters/index.md),
 you can connect a Kubernetes cluster to the GitLab instance and use the same cluster across all of

doc/api/project_clusters.md

@@ -4,9 +4,13 @@ group: Configure
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
-# Project clusters API **(FREE)**
+# Project clusters API (certificate-based) (DEPRECATED) **(FREE)**
 
-> [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/23922) in GitLab 11.7.
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/23922) in GitLab 11.7.
+> - [Deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
+
+WARNING:
+This feature was [deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
 
 Users need at least the [Maintainer](../user/permissions.md) role to use these endpoints.
 

doc/user/clusters/applications.md

@@ -20,7 +20,7 @@ methods: "one-click install" and "CI/CD template". Both methods are **deprecated
 
 Both methods were limiting as you couldn't fully customize your third-party apps installed
 through GitLab Managed Apps. Therefore, we decided to deprecate this feature and provide
-better [GitOps-driven alternatives](https://about.gitlab.com/direction/configure/kubernetes_management/#gitlab-managed-applications) to our users, such as [cluster integrations](integrations.md#cluster-integrations) and [cluster management project](management_project.md).
+better [GitOps-driven alternatives](https://about.gitlab.com/direction/configure/kubernetes_management/#gitlab-managed-applications) to our users, such as [cluster integrations](integrations.md) and [cluster management project](management_project.md).
 
 ## Install using GitLab CI/CD (DEPRECATED)
 

doc/user/clusters/cost_management.md

@@ -4,9 +4,13 @@ group: Configure
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
-# Cluster cost management **(ULTIMATE)**
+# Cluster cost management (DEPRECATED) **(ULTIMATE)**
 
-> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/216737) in [GitLab Ultimate](https://about.gitlab.com/pricing/) 13.5.
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/216737) in [GitLab Ultimate](https://about.gitlab.com/pricing/) 13.5.
+> - [Deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
+
+WARNING:
+This feature was [deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
 
 Cluster cost management provides insights into cluster resource usage. GitLab provides an example
 [`kubecost-cost-model`](https://gitlab.com/gitlab-examples/kubecost-cost-model/)

doc/user/clusters/crossplane.md

@@ -4,7 +4,12 @@ group: Configure
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
-# Crossplane configuration **(FREE)**
+# Crossplane configuration (DEPRECATED) **(FREE)**
+
+> [Deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
+
+WARNING:
+This feature was [deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
 
 After [installing](applications.md#install-crossplane-using-gitlab-cicd) Crossplane, you must configure it for use.
 The process of configuring Crossplane includes:

doc/user/clusters/environments.md

@@ -4,10 +4,14 @@ group: Configure
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
-# Cluster Environments **(PREMIUM)**
+# Cluster Environments (DEPRECATED) **(PREMIUM)**
 
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/13392) in [GitLab Premium](https://about.gitlab.com/pricing/) 12.3 for group-level clusters.
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/14809) in [GitLab Premium](https://about.gitlab.com/pricing/) 12.4 for instance-level clusters.
+> - [Deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
+
+WARNING:
+This feature was [deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
 
 Cluster environments provide a consolidated view of which CI [environments](../../ci/environments/index.md) are
 deployed to the Kubernetes cluster and it:

doc/user/clusters/integrations.md

@@ -4,14 +4,19 @@ group: Configure
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
-# Cluster integrations **(FREE)**
+# Cluster integrations (DEPRECATED) **(FREE)**
+
+> [Deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
+
+WARNING:
+This feature was [deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
 
 GitLab provides several ways to integrate applications to your
 Kubernetes cluster.
 
 To enable cluster integrations, first add a Kubernetes cluster to a GitLab
 [project](../project/clusters/add_remove_clusters.md) or
-[group](../group/clusters/index.md#group-level-kubernetes-clusters) or
+[group](../group/clusters/index.md) or
 [instance](../instance/clusters/index.md).
 
 You can install your applications manually as shown in the following sections, or use the
@@ -36,6 +41,11 @@ Follow this [issue](https://gitlab.com/gitlab-org/gitlab/-/issues/300230) for up
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/55244) in GitLab 13.11.
 
+WARNING:
+This feature was [deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5. However, you can **still use** Prometheus
+for Kubernetes clusters connected to GitLab through the
+[GitLab Kubernetes Agent](agent/index.md) by [enabling Prometheus manually](../project/integrations/prometheus.md#manual-configuration-of-prometheus).
+
 You can integrate your Kubernetes cluster with
 [Prometheus](https://prometheus.io/) for monitoring key metrics of your
 apps directly from the GitLab UI.

doc/user/clusters/management_project.md

@@ -4,9 +4,13 @@ group: Configure
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
-# Cluster management project **(FREE)**
+# Cluster management project (DEPRECATED) **(FREE)**
 
-> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/32810) in GitLab 12.5
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/32810) in GitLab 12.5.
+> - [Deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
+
+WARNING:
+This feature was [deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
 
 A project can be designated as the management project for a cluster.
 A management project can be used to run deployment jobs with

doc/user/group/clusters/index.md

@@ -5,9 +5,14 @@ group: Configure
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
-# Group-level Kubernetes clusters **(FREE)**
+# Group-level Kubernetes clusters (certificate-based) (DEPRECATED) **(FREE)**
 
-> [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/issues/34758) in GitLab 11.6.
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/issues/34758) in GitLab 11.6.
+> - [Deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
+
+WARNING:
+This feature was [deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5. To connect clusters to GitLab,
+use the [GitLab Kubernetes Agent](../../clusters/agent/index.md).
 
 Similar to [project-level](../../project/clusters/index.md) and
 [instance-level](../../instance/clusters/index.md) Kubernetes clusters,

doc/user/instance/clusters/index.md

@@ -4,9 +4,14 @@ group: unassigned
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
-# Instance-level Kubernetes clusters **(FREE SELF)**
+# Instance-level Kubernetes clusters (certificate-based) (DEPRECATED) **(FREE SELF)**
 
-> [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/issues/39840) in GitLab 11.11.
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/issues/39840) in GitLab 11.11.
+> - [Deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
+
+WARNING:
+This feature was [deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5. To connect clusters to GitLab,
+use the [GitLab Kubernetes Agent](../../clusters/agent/index.md).
 
 Similar to [project-level](../../project/clusters/index.md)
 and [group-level](../../group/clusters/index.md) Kubernetes clusters,

doc/user/project/clusters/index.md

@@ -4,26 +4,22 @@ group: Configure
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
-# Project-level Kubernetes clusters with cluster certificates (DEPRECATED) **(FREE)**
+# Project-level Kubernetes clusters (certificate-based) (DEPRECATED) **(FREE)**
 
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/issues/35954) in GitLab 10.1.
 > - [Deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8) in GitLab 14.5.
 
 WARNING:
-Project-level Kubernetes clusters with cluster certificates was
-[deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8)
-in GitLab 14.5.
-To connect your cluster to GitLab, use the [GitLab Kubernetes Agent](../../../user/clusters/agent/index.md).
+This feature was [deprecated](https://gitlab.com/groups/gitlab-org/configure/-/epics/8)
+in GitLab 14.5. To connect clusters to GitLab, use the
+[GitLab Kubernetes Agent](../../clusters/agent/index.md).
 
-[Project-level Kubernetes clusters](../../infrastructure/clusters/connect/index.md#cluster-levels)
+[Project-level Kubernetes clusters](../../infrastructure/clusters/index.md#cluster-levels)
 allow you to connect a Kubernetes cluster to a project in GitLab.
 
 You can also [connect multiple clusters](multiple_kubernetes_clusters.md)
 to a single project.
 
-After connecting a cluster to GitLab, you can benefit from the large number of
-[GitLab features available for Kubernetes clusters](../../infrastructure/clusters/index.md) to manage and deploy to your cluster.
-
 ## View your project-level clusters
 
 To view project-level Kubernetes clusters: