Alerting/Docs: Silence documentation (#35052)

Co-authored-by: David Parrott <stomp.box.yo@gmail.com>
Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

docs/sources/alerting/unified-alerting/silences.md

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+title = "Silence alert notifications"
+description = "Silence alert notifications"
+keywords = ["grafana", "alerting", "silence", "mute"]
+weight = 400
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+
+# Silence alert notifications
+
+Grafana allows to you to prevent notifications from one or more alert rules by creating a silence. This silence lasts for a specified window of time.
+
+Silences do not prevent alert rules from being evaluated. They also do not stop alert instances being shown in the user interface. Silences only prevent notifications from being created.
+
+## Add a silence
+
+To add a silence:
+
+1. In the Grafana menu, hover your cursor over the **Alerting** (bell) icon and then select **Silences** (crossed out bell icon).
+1. Click the **New Silence** button.
+1. Select the start and end date in **Silence start and end** to indicate when the silence should go into effect and expire.
+1. Optionally, update the **Duration** to alter the time for the end of silence in the previous step to correspond to the start plus the duration.
+1. Enter one or more *Matching Labels* by filling out the **Name** and **Value** fields. Matchers determine which rules the silence will apply to.
+1. Enter a **Comment**.
+1. Enter the name of the owner in **Creator**.
+1. Click **Create**.
+
+## How label matching works
+
+Alert instances that have labels that match all of the "Matching Labels" specified in the silence will have their notifications suppressed.
+
+- The **Label** field is the name of the label to match. It must exactly match the label name.
+- The **Value** field matches against the corresponding value for the specified **Label** name. How it matches depends on the **Regex** and **Equal** checkboxes.
+- The **Regex** checkbox specifies if the inputted **Value** should be matched against labels as a regular expression. The regular expression is always anchored. If not selected it is an exact string match.
+- The **Equal** checkbox specifies if the match should include alert instances that match or do not match. If not checked, the silence includes alert instances _do not_ match.
+
+## Viewing and editing silences
+
+1. In the Grafana menu hover your cursor over the **Alerting** (bell) icon, then select **Silences** (crossed out bell icon).
+1. To end the silence, click the **Unsilence** option next to the listed silence. Silences that have ended are still listed and are automatically removed after 5 days. There is no method for manual removal.
+1. To edit a silence, click the pencil icon next to the listed silence. Edit the silence using instructions on how to create a silence.
+1. Click **Submit** to save your changes.