Add CortexRolloutStuck alert

Signed-off-by: Marco Pracucci <[email protected]>

Author: pracucci

CHANGELOG.md

@@ -64,6 +64,7 @@
 * [ENHANCEMENT] Add support for running Alertmanager in sharding mode. #394
 * [ENHANCEMENT] Allow to customize PromQL engine settings via `queryEngineConfig`. #399
 * [ENHANCEMENT] Add recording rules to improve responsiveness of Alertmanager dashboard. #387
+* [ENHANCEMENT] Add `CortexRolloutStuck` alert. #405
 * [BUGFIX] Fixed `CortexIngesterHasNotShippedBlocks` alert false positive in case an ingester instance had ingested samples in the past, then no traffic was received for a long period and then it started receiving samples again. #308
 * [BUGFIX] Alertmanager: fixed `--alertmanager.cluster.peers` CLI flag passed to alertmanager when HA is enabled. #329
 * [BUGFIX] Fixed `CortexInconsistentRuntimeConfig` metric. #335

cortex-mixin/alerts/alerts.libsonnet

@@ -412,6 +412,67 @@
         },
       ],
     },
+    {
+      name: 'cortex-rollout-alerts',
+      rules: [
+        {
+          alert: 'CortexRolloutStuck',
+          expr: |||
+            (
+              max without (revision) (
+                kube_statefulset_status_current_revision
+                  unless
+                kube_statefulset_status_update_revision
+              )
+                *
+              (
+                kube_statefulset_replicas
+                  !=
+                kube_statefulset_status_replicas_updated
+              )
+            )  and (
+              changes(kube_statefulset_status_replicas_updated[15m])
+                ==
+              0
+            )
+            * on(%s) group_left max by(%s) (cortex_build_info)
+          ||| % [$._config.alert_aggregation_labels, $._config.alert_aggregation_labels],
+          'for': '15m',
+          labels: {
+            severity: 'warning',
+          },
+          annotations: {
+            message: |||
+              The {{ $labels.statefulset }} rollout is stuck in %(alert_aggregation_variables)s.
+            ||| % $._config,
+          },
+        },
+        {
+          alert: 'CortexRolloutStuck',
+          expr: |||
+            (
+              kube_deployment_spec_replicas
+                !=
+              kube_deployment_status_replicas_updated
+            ) and (
+              changes(kube_deployment_status_replicas_updated[15m])
+                ==
+              0
+            )
+            * on(%s) group_left max by(%s) (cortex_build_info)
+          ||| % [$._config.alert_aggregation_labels, $._config.alert_aggregation_labels],
+          'for': '15m',
+          labels: {
+            severity: 'warning',
+          },
+          annotations: {
+            message: |||
+              The {{ $labels.deployment }} rollout is stuck in %(alert_aggregation_variables)s.
+            ||| % $._config,
+          },
+        },
+      ],
+    },
     {
       name: 'cortex-provisioning',
       rules: [

cortex-mixin/docs/playbooks.md

@@ -231,6 +231,16 @@ How to **investigate**:
 
 _If the alert `CortexIngesterTSDBHeadCompactionFailed` fired as well, then give priority to it because that could be the cause._
 
+### CortexRolloutStuck
+
+This alert fires when a Cortex service rollout is stuck, which means the number of updated replicas doesn't match the expected one and looks there's no progress in the rollout. The alert monitors services deployed as Kubernetes `StatefulSet` and `Deployment`.
+
+How to **investigate**:
+- Run `kubectl -n <namespace> get pods -l name=<statefulset|deployment>` to get a list of running pods
+- Ensure there's no pod in a failing state (eg. `Error`, `OOMKilled`, `CrashLoopBackOff`)
+- Ensure there's no pod `NotReady` (the number of ready containers should match the total number of containers, eg. `1/1` or `2/2`)
+- Run `kubectl -n <namespace> describe statefulset <name>` or `kubectl -n <namespace> describe deployment <name>` and look at "Pod Status" and "Events" to get more information
+
 #### Ingester hit the disk capacity
 
 If the ingester hit the disk capacity, any attempt to append samples will fail. You should: