feat: enhance Redis metrics with additional alerts and labels in production configuration

Signed-off-by: zhenyus <zhenyus@mathmast.com>

freeleaps/helm-pkg/3rd/redis-cluster/values.prod.yaml

@@ -1076,8 +1076,9 @@ metrics:
   ##
   prometheusRule:
     enabled: true
-    additionalLabels: {}
-    namespace: ""
+    additionalLabels:
+      release: kube-prometheus-stack
+    namespace: "freeleaps-monitoring-system"
     ## These are just examples rules, please adapt them to your needs.
     ## Make sure to constraint the rules to the current postgresql service.
     ##  - alert: RedisDown
@@ -1109,7 +1110,35 @@ metrics:
     ##      summary: Redis® instance {{ "{{ $instance }}" }} has evicted keys
     ##      description: Redis® instance {{ "{{ $instance }}" }} has evicted {{ "{{ $value }}" }} keys in the last 5 minutes.
     ##
-    rules: []
+    rules: 
+     - alert: RedisDown
+       expr: redis_up{service="{{ template "common.names.fullname" . }}-metrics"} == 0
+       for: 2m
+       labels:
+         severity: error
+       annotations:
+         summary: Redis® instance {{ "{{ $instance }}" }} down
+         description: Redis® instance {{ "{{ $instance }}" }} is down.
+     - alert: RedisMemoryHigh
+       expr: >
+          redis_memory_used_bytes{service="{{ template "common.names.fullname" . }}-metrics"} * 100
+          /
+          redis_memory_max_bytes{service="{{ template "common.names.fullname" . }}-metrics"}
+          > 90
+       for: 2m
+       labels:
+         severity: error
+       annotations:
+         summary: Redis® instance {{ "{{ $instance }}" }} is using too much memory
+         description: Redis® instance {{ "{{ $instance }}" }} is using {{ "{{ $value }}" }}% of its available memory.
+     - alert: RedisKeyEviction
+       expr: increase(redis_evicted_keys_total{service="{{ template "common.names.fullname" . }}-metrics"}[5m]) > 0
+       for: 1s
+       labels:
+         severity: error
+       annotations:
+         summary: Redis® instance {{ "{{ $instance }}" }} has evicted keys
+         description: Redis® instance {{ "{{ $instance }}" }} has evicted {{ "{{ $value }}" }} keys in the last 5 minutes.
   ## @param metrics.priorityClassName Metrics exporter pod priorityClassName
   ##
   priorityClassName: ""