Merge branch 'docs-instance_level_clusters' into 'master'

Initial instance level cluster docs

See merge request gitlab-org/gitlab-ce!27873

(cherry picked from commit 961a5f72)

96cec8bf Initial instance level cluster docs
a951adb6 Apply suggestion to doc/user/project/clusters/index.md
719b7a07 Apply suggestion to doc/user/group/clusters/index.md

doc/user/group/clusters/index.md

@@ -5,10 +5,10 @@
 
 ## Overview
 
-Similar to [project Kubernetes
-clusters](../../project/clusters/index.md), Group-level Kubernetes
-clusters allow you to connect a Kubernetes cluster to your group,
-enabling you to use the same cluster across multiple projects.
+Similar to [project-level](../../project/clusters/index.md) and
+[instance-level](../../instance/clusters/index.md) Kubernetes clusters,
+group-level Kubernetes clusters allow you to connect a Kubernetes cluster to
+your group, enabling you to use the same cluster across multiple projects.
 
 ## Installing applications
 

doc/user/instance/clusters/index.md

+# Instance-level Kubernetes clusters
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab-ce/issues/39840) in GitLab 11.11.
+> Instance-level cluster integration is currently in [Beta](https://about.gitlab.com/handbook/product/#alpha-beta-ga).
+
+## Overview
+
+Similar to [project-level](../../project/clusters/index.md)
+and [group-level](../../group/clusters/index.md) Kubernetes clusters,
+instance-level Kubernetes clusters allow you to connect a Kubernetes cluster to
+the GitLab instance, which enables you to use the same cluster across multiple
+projects.
+
+## Cluster precedence
+
+GitLab will try match to clusters in the following order:
+
+- Project-level clusters
+- Group-level clusters
+- Instance level
+
+To be selected, the cluster must be enabled and
+match the [environment selector](../../../ci/environments.md#scoping-environments-with-specs-premium).

doc/user/project/clusters/index.md

@@ -19,8 +19,10 @@ or provide the credentials to an [existing Kubernetes cluster](#adding-an-existi
 
 NOTE: **Note:**
 From [GitLab 11.6](https://gitlab.com/gitlab-org/gitlab-ce/issues/34758) you
-can also associate a Kubernetes cluster to your groups. Learn more about
-[group Kubernetes clusters](../../group/clusters/index.md).
+can also associate a Kubernetes cluster to your groups and from
+[GitLab 11.11](https://gitlab.com/gitlab-org/gitlab-ce/issues/39840),
+to the GitLab instance. Learn more about [group-level](../../group/clusters/index.md)
+and [instance-level](../../instance/clusters/index.md) Kubernetes clusters.
 
 ## Adding and creating a new GKE cluster via GitLab