Added instruction how to silence alerts

README.md

@@ -43,6 +43,7 @@ The aim of this project is to have a quick guide of what to do when an emergency
 ## Alerting and monitoring
 * [How to add alerts: Alerts manual](howto/alerts_manual.md)
+* [How to silence alerts](howto/silence-alerts.md)
 * [Alert for SSL certificate expiration](howto/alert-for-ssl-certificate-expiration.md)
 * [Working with Grafana](monitoring/grafana.md)
 * [Working with Prometheus](monitoring/prometheus.md)

howto/silence-alerts.md

+## View alerts
+
+1. Current alerts are being alerted can be viewed on https://alerts.gitlab.com/#/alerts
+1. Silenced alerts can be viewed on https://alerts.gitlab.com/#/silences 
+
+## Silence alerts
+
+Silences can be added in two ways:
+1. By explicitly creating silence (`New Silence` button) on [silences](https://alerts.gitlab.com/#/silences) page. Enter start, end, creator, reason and condition for silencing.
+![silence example](../img/manual-silence-example.png)
+1. By silencing from [alerts] page. Conditions for silencing automatically taken from alert labels.
+![silence example](../img/alert-silence-example.png)
+1. You can unsilence alert by clicking `Expire` on silence entry.