feat: enhance configuration files with detailed comments for clarity

config/instance-down-rules.yml

@@ -1,30 +1,31 @@
+# Default Prometheus alert groups for OpenIM.
 groups:
-  - name: instance_down
+  - name: instance_down # Fires when a monitored target remains unreachable.
     rules:
       - alert: InstanceDown
-        expr: up == 0
-        for: 1m
+        expr: up == 0 # The built-in "up" metric is 0 when the latest scrape fails.
+        for: 1m # Trigger only if the condition remains true for more than 1 minute.
         labels:
-          severity: critical
+          severity: critical # Used by Alertmanager for routing and notification priority.
         annotations:
           summary: "Instance {{ $labels.instance }} down"
-          description: "{{ $labels.instance }} of job {{ $labels.job }} has been down for more than 1 minutes."
+          description: "{{ $labels.instance }} of job {{ $labels.job }} has been down for more than 1 minute."
 
-  - name: database_insert_failure_alerts
+  - name: database_insert_failure_alerts # Detects failures when persisting messages to Redis or MongoDB.
     rules:
       - alert: DatabaseInsertFailed
-        expr: (increase(msg_insert_redis_failed_total[5m]) > 0) or (increase(msg_insert_mongo_failed_total[5m]) > 0)
-        for: 1m
+        expr: (increase(msg_insert_redis_failed_total[5m]) > 0) or (increase(msg_insert_mongo_failed_total[5m]) > 0) # Any positive increase indicates write failures occurred in the last 5 minutes.
+        for: 1m # Avoid firing on very short spikes.
         labels:
           severity: critical
         annotations:
           summary: "Increase in MsgInsertRedisFailedCounter or MsgInsertMongoFailedCounter detected"
-          description: "Either MsgInsertRedisFailedCounter or MsgInsertMongoFailedCounter has increased in the last 5 minutes, indicating failures in message insert operations to Redis or MongoDB,maybe the redis or mongodb is crash."
+          description: "Either MsgInsertRedisFailedCounter or MsgInsertMongoFailedCounter increased in the last 5 minutes, indicating message insert failures to Redis or MongoDB and a possible backend outage."
 
-  - name: registrations_few
+  - name: registrations_few # Operational early-warning rule for unusually low login/registration activity.
     rules:
       - alert: RegistrationsFew
-        expr: increase(user_login_total[1h]) == 0
+        expr: increase(user_login_total[1h]) == 0 # No successful login/registration events observed in 1 hour.
         for: 1m
         labels:
           severity: info
@@ -32,10 +33,10 @@ groups:
           summary: "Too few registrations within the time frame"
           description: "The number of registrations in the last hour is 0. There might be some issues."
 
-  - name: messages_few
+  - name: messages_few # Operational early-warning rule for unusually low messaging activity.
     rules:
       - alert: MessagesFew
-        expr: (increase(single_chat_msg_process_success_total[1h])+increase(group_chat_msg_process_success_total[1h])) == 0
+        expr: (increase(single_chat_msg_process_success_total[1h])+increase(group_chat_msg_process_success_total[1h])) == 0 # No successful single or group messages observed in 1 hour.
         for: 1m
         labels:
           severity: info