How did the Redis Sentinel cooperate
Redis Sentinel achieves high availability by coordinating work to monitor and manage Redis instances. Key tasks include: Monitoring instance election leader performs failover processing configuration changes Sentinels communicate via the Gossip protocol. For optimal collaboration, it is recommended to deploy at least three sentinel instances, select different hosts, and monitor them.
Redis Sentinels work together
Redis Sentinel is a high availability solution for monitoring and managing Redis instances, ensuring automatic failover and failure recovery in the event of failure.
Sentinels work together
Sentinel instance coordinates work to perform the following key tasks:
1. Monitor Redis instances
Sentinels monitor Redis instances by sending PING commands regularly. If the Sentinel cannot communicate with the instance, it marks the instance as a failure.
2. Election of leadership sentinel
In the presence of multiple sentinels, the sentinel will elect a leading sentinel. Leader Sentinel coordinates failover and configuration changes.
3. Failover
When a sentinel detects a failure, it initiates a failover process. Lead sentinel selects a new master node and promotes the replica to the master node.
4. Configuration changes
Leader Sentinel is responsible for handling configuration changes, such as adding or removing instances. It propagates changes to all sentinel instances, ensuring they have the latest cluster information.
Communication Protocol
Sentinels use the Gossip protocol to communicate. This protocol allows sentries to exchange information with each other and keep synchronized to the cluster state.
Deployment precautions
To achieve optimal sentinel collaboration, follow these best practices:
- Deploy at least three sentinel instances to ensure redundancy.
- Select different hosts for the Sentinel instance to reduce the risk of failure.
- Monitor sentinel instances and take action in the event of a failure.
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