Update Kubernetes service documentation

States this service was deprecated on 10.3 and his behavior depends on
the kubernetes service status. Also includes a link for the release post
for more information.

doc/api/services.md

@@ -494,6 +494,9 @@ DELETE /projects/:id/services/jira
 
 Kubernetes / Openshift integration
 
+CAUTION: **Warning:**
+Kubernetes service integration has been deprecated in GitLab 10.3. API service endpoints will continue to work as long as the Kubernetes service is active, however if the service is inactive API endpoints will automatically return a `400 Bad Request`. Read [GitLab 10.3 release post](https://about.gitlab.com/2017/12/22/gitlab-10-3-released/#kubernetes-integration-service) for more information.
+
 ### Create/Edit Kubernetes service
 
 Set Kubernetes service for a project.

doc/user/project/integrations/kubernetes.md

@@ -2,6 +2,9 @@
 last_updated: 2017-09-25
 ---
 
+CAUTION: **Warning:**
+Kubernetes service integration has been deprecated in GitLab 10.3. If the service is active the cluster information still be editable, however we advised to disable and reconfigure the clusters using the new [Clusters](../clusters/index.md) page. If the service is inactive the fields will be uneditable. Read [GitLab 10.3 release post](https://about.gitlab.com/2017/12/22/gitlab-10-3-released/#kubernetes-integration-service) for more information.
+
 # GitLab Kubernetes / OpenShift integration
 
 GitLab can be configured to interact with Kubernetes, or other systems using the

doc/user/project/integrations/project_services.md

@@ -40,7 +40,7 @@ Click on the service links to see further configuration instructions and details
 | [JIRA](jira.md) | JIRA issue tracker |
 | [Jenkins](../../../integration/jenkins.md) | An extendable open source continuous integration server |
 | JetBrains TeamCity CI | A continuous integration and build server |
-| [Kubernetes](kubernetes.md) | A containerized deployment service |
+| [Kubernetes](kubernetes.md) _(Has been deprecated in GitLab 10.3)_ | A containerized deployment service |
 | [Mattermost slash commands](mattermost_slash_commands.md) | Mattermost chat and ChatOps slash commands |
 | [Mattermost Notifications](mattermost.md) | Receive event notifications in Mattermost |
 | [Microsoft teams](microsoft_teams.md) |  Receive notifications for actions that happen on GitLab into a room on Microsoft Teams using Office 365 Connectors |