From 6b304750ad8c411d21bc0bc50b8e631d299fa078 Mon Sep 17 00:00:00 2001
From: Brian Burt <bburt@redhat.com>
Date: Mon, 13 Sep 2021 10:02:06 -0400
Subject: [PATCH] Added content for disabling the Alertmanager in the
 Monitoring stack

---
 ...ring-disabling-the-local-alertmanager.adoc | 43 +++++++++++++++++++
 .../configuring-the-monitoring-stack.adoc     |  7 +++
 2 files changed, 50 insertions(+)
 create mode 100644 modules/monitoring-disabling-the-local-alertmanager.adoc

diff --git a/modules/monitoring-disabling-the-local-alertmanager.adoc b/modules/monitoring-disabling-the-local-alertmanager.adoc
new file mode 100644
index 0000000000..2077ef8d85
--- /dev/null
+++ b/modules/monitoring-disabling-the-local-alertmanager.adoc
@@ -0,0 +1,43 @@
+// Module included in the following assemblies:
+//
+// * monitoring/configuring-the-monitoring-stack.adoc
+
+[id="monitoring-disabling-the-local-alertmanager_{context}"]
+= Disabling the local Alertmanager
+
+A local Alertmanager that routes alerts from Prometheus instances is enabled by default in the `openshift-monitoring` project of the {product-title} monitoring stack.
+
+If you do not need the local Alertmanager, you can disable it by configuring the `cluster-monitoring-config` config map in the `openshift-monitoring` project.
+
+.Prerequisites
+
+* You have access to the cluster as a user with the `cluster-admin` role.
+* You have created the `cluster-monitoring-config` config map.
+* You have installed the OpenShift CLI (`oc`).
+
+.Procedure
+
+. Edit the `cluster-monitoring-config` config map in the `openshift-monitoring` project:
++
+[source,terminal]
+----
+$ oc -n openshift-monitoring edit configmap cluster-monitoring-config
+----
+
+. Add `enabled: false` for the `alertmanagerMain` component under `data/config.yaml`:
++
+[source,yaml]
+----
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: cluster-monitoring-config
+  namespace: openshift-monitoring
+data:
+  config.yaml: |
+    alertmanagerMain:
+      enabled: false
+----
+
+. Save the file to apply the changes. The Alertmanager instance is disabled automatically when you apply the change.
+
diff --git a/monitoring/configuring-the-monitoring-stack.adoc b/monitoring/configuring-the-monitoring-stack.adoc
index 9e90f09b87..4d892fefc4 100644
--- a/monitoring/configuring-the-monitoring-stack.adoc
+++ b/monitoring/configuring-the-monitoring-stack.adoc
@@ -140,6 +140,13 @@ include::modules/monitoring-disabling-grafana.adoc[leveloffset=+1]
 
 * See xref:../monitoring/configuring-the-monitoring-stack.adoc#preparing-to-configure-the-monitoring-stack[Preparing to configure the monitoring stack] for steps to create monitoring config maps
 
+// Disabling the local Alertmanager
+include::modules/monitoring-disabling-the-local-alertmanager.adoc[leveloffset=+1]
+
+.Additional resources
+* link:https://prometheus.io/docs/alerting/latest/alertmanager/[Prometheus Alertmanager documentation]
+* xref:../monitoring/managing-alerts.adoc#[Managing alerts]
+
 == Next steps
 
 * xref:../monitoring/enabling-monitoring-for-user-defined-projects.adoc#enabling-monitoring-for-user-defined-projects[Enabling monitoring for user-defined projects]