Docs: pull labels and label matchers in to its own fundamentals article (#48758)

docs/sources/alerting/fundamentals/labels-and-label-matchers.md

@@ -0,0 +1,43 @@
++++
+title = "Labels and label matchers"
+description = "Learn about labels and label matchers in alerting"
+keywords = ["grafana", "alerting", "guide", "fundamentals"]
+weight = 117
++++
+
+# Labels and label matchers
+
+To link alert rules to various other alerting concepts like [notification policies]() and [silences]() you make use of labels and label matchers.
+
+This allows for a very flexible way to manage your alert instances, what policy should handle them and which alerts to silence.
+
+## How label matching works
+
+A label matchers consists of 3 distinct parts, the **label**, the **value** and the **operator**.
+
+- 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 **Operator** value.
+
+- The **Operator** field is the operator to match against the label value. The available operators are:
+
+| Operator | Description                                        |
+| -------- | -------------------------------------------------- |
+| `=`      | Select labels that are exactly equal to the value. |
+| `!=`     | Select labels that are not equal to the value.     |
+| `=~`     | Select labels that regex-match the value.          |
+| `!~`     | Select labels that do not regex-match the value.   |
+
+## Example
+
+Imagine we've defined the following set of labels for our alert.
+
+`{ foo=bar, baz=qux, id=12 }`
+
+A label matcher defined as `foo=bar` will match this alert rule.
+
+A label matcher defined as `foo!=bar` will _not_ match this alert rule.
+
+A label matcher defined as `id=~[0-9]+` will match this alert rule.
+
+A label matcher defined as `baz!~[0-9]+` will match this alert rule.

docs/sources/alerting/notifications/_index.md

@@ -48,7 +48,7 @@ You can configure grouping to be `group_by: [alertname]` (take note that the `en
 1. Click **Notification policies**.
 1. From the **Alertmanager** dropdown, select an Alertmanager. By default, the Grafana Alertmanager is selected.
 1. To add a top level specific policy, go to the **Specific routing** section and click **New specific policy**.
-1. In **Matching labels** section, add one or more rules for matching alert labels. For more information, see ["How label matching works"](#how-label-matching-works).
+1. In **Matching labels** section, add one or more rules for matching alert labels. For more information, see ["Labels and label matchers"]({{< relref "../fundamentals/labels-and-label-matchers.md" >}}).
 1. In **Contact point**, add the [contact point]({{< relref "../contact-points/_index.md" >}}) to send notification to if alert matches only this specific policy and not any of the nested policies.
 1. Optionally, enable **Continue matching subsequent sibling nodes** to continue matching nested policies even after the alert matched the parent policy. When this option is enabled, you can get more than one notification. Use it to send notification to a catch-all contact point as well as to one of more specific contact points handled by nested policies.
 1. Optionally, enable **Override grouping** to specify the same grouping as the root policy. If this option is not enabled, the root policy grouping is used.
@@ -68,20 +68,6 @@ You can configure grouping to be `group_by: [alertname]` (take note that the `en
 1. Make any changes using instructions in [Add new specific policy](#add-new-specific-policy).
 1. Click **Save policy**.
 
-## How label matching works
-
-A policy will match an alert if the alert's labels match all the "Matching Labels" specified on the policy.
-
-- The **Label** field is the name of the label to match. It must exactly match the label name.
-- The **Operator** field is the operator to match against the label value. The available operators are:
-
-  - `=`: Select labels that are exactly equal to the provided string.
-  - `!=`: Select labels that are not equal to the provided string.
-  - `=~`: Select labels that regex-match the provided string.
-  - `!~`: Select labels that do not regex-match the provided string.
-
-- The **Value** field matches against the corresponding value for the specified **Label** name. How it matches depends on the **Operator** value.
-
 ## Example
 
 An example of an alert configuration.