RedisNotEnoughConnections #

Redis instance should have more connections (> 5)

alert: RedisNotEnoughConnections
annotations:
  description: |-
    Redis instance should have more connections (> 5)
      VALUE = {{ $value }}
      LABELS = {{ $labels }}    
  runbook: https://srerun.github.io/prometheus-alerts/runbooks/oliver006-redis-exporter/redisnotenoughconnections/
  summary: Redis not enough connections (instance {{ $labels.instance }})
expr: redis_connected_clients < 5
for: 2m
labels:
  severity: warning

Here is a runbook for the RedisNotEnoughConnections alert:

Meaning #

The RedisNotEnoughConnections alert is triggered when the number of connected clients to a Redis instance falls below 5 for a period of 2 minutes. This alert indicates that the Redis instance may not be able to handle the load or may be experiencing connectivity issues.

Impact #

If this alert is not addressed, it can lead to:

• Poor performance and responsiveness of applications that rely on Redis
• Increased latency and timeouts for Redis requests
• Potential data loss or inconsistencies due to unprocessed requests
• Downtime and unavailability of critical systems that depend on Redis

Diagnosis #

To diagnose the root cause of this alert, follow these steps:

1. Check the Redis instance logs for errors or warnings related to connection issues.
2. Verify that the Redis instance is correctly configured and running with the recommended settings.
3. Investigate if there are any network connectivity issues between the clients and the Redis instance.
4. Review the client connection metrics to identify any patterns or trends that may be contributing to the low connection count.
5. Check the system resources (CPU, memory, disk space) to ensure they are not overwhelmed.

Mitigation #

To mitigate this alert, follow these steps:

1. Increase the Redis instance’s connection limit to accommodate the expected load.
2. Optimize the Redis instance configuration to improve performance and responsiveness.
3. Implement connection pooling or pipelining to reduce the number of connections required.
4. Investigate and resolve any underlying network connectivity issues.
5. Monitor the Redis instance and client connections closely to identify and address any recurring issues.
6. Consider scaling up the Redis instance or distributing the load across multiple instances to improve performance and availability.