Remove crsync absent deployments alerts (#1150)

It causes false triggers because the MC where the rule is applied
has multiple prometheus instances and they all take the rule into
account, but only the operations one should have the alert.

We can get it back online when we has a single instance / mimir.

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Removed
+
+- Removed alerts for absent `crsync` deployments. They cause false alerts because the rules apply to all prometheus instances on the MC.
+
 ## [3.13.0] - 2024-04-30
 
 ### Added

helm/prometheus-rules/templates/alerting-rules/crsync.rules.yml

@@ -13,36 +13,6 @@ spec:
   groups:
   - name: crsync
     rules:
-    - alert: CrsyncDockerIoIsMissing
-      annotations:
-        description: 'CrSync deployment for docker.io is absent'
-        opsrecipe: crsync-deployments-missing/
-      expr: absent(kube_deployment_status_replicas_available{namespace="crsync", deployment="crsync-docker-io"})
-      for: 10m
-      labels:
-        area: kaas
-        cancel_if_cluster_status_creating: "true"
-        cancel_if_cluster_status_deleting: "true"
-        cancel_if_cluster_status_updating: "true"
-        cancel_if_outside_working_hours: "true"
-        severity: page
-        team: honeybadger
-        topic: releng
-    - alert: CrsyncGiantswarmAzureCrIoIsMissing
-      annotations:
-        description: 'CrSync deployment for giantswarm.azurecr.io is absent'
-        opsrecipe: crsync-deployments-missing/
-      expr: absent(kube_deployment_status_replicas_available{namespace="crsync", deployment="crsync-giantswarm-azurecr-io"})
-      for: 10m
-      labels:
-        area: kaas
-        cancel_if_cluster_status_creating: "true"
-        cancel_if_cluster_status_deleting: "true"
-        cancel_if_cluster_status_updating: "true"
-        cancel_if_outside_working_hours: "true"
-        severity: page
-        team: honeybadger
-        topic: releng
     - alert: CrsyncDeploymentNotSatisfied
       annotations:
         description: '{{`CrSync deployment {{ $labels.deployment }} is not satisfied in {{ $labels.installation }} / {{ $labels.cluster_id }} at the {{ $labels.namespace }} namespace.`}}'