How to use Redis sentinel
Redis Sentinel is a high availability solution for Redis services that ensures service availability by monitoring Redis instances and failover. It requires the installation of Redis Sentinel and the configuration of the sentinel.conf file. Sentinel will continuously monitor the Redis instance and perform master-slave failover based on the voting results to ensure the continuous availability of the service.
Redis Sentinel Guide
1. Introduction
Redis Sentinel is a high availability solution for Redis services that automatically monitor master-slave Redis instances and failover.
2. Installation and configuration
- Install Redis Sentinel, which can be downloaded on the Redis official website.
- Create a sentinel.conf configuration file that specifies the monitored Redis instance and voting threshold.
- Start Redis Sentinel:
redis-sentinel sentinel.conf
3. Monitoring and Failover
- Sentinel continuously monitors the master-slave Redis instance and triggers failover if a failure is detected.
- Failover requires more than half of the sentinels to vote for agreement to ensure consistency.
- Sentinel will automatically promote the new master instance to a writeable replica and downgrade the original master instance to a read replica.
4. Advanced features
- Automatic fault detection: Sentinels will send PING commands regularly, and if the main instance fails to respond, fault detection will be triggered.
- Master-slave Failover: Sentinels can fail over to a specified master-slave instance for customized troubleshooting.
- Automated configuration: Sentinel automatically updates configuration to reflect instance failure and recovery.
V. Best Practices
- Deploy odd sentinel instances to avoid a voting draw.
- Ensure that there is a good network connection between the Sentinel and the server where the Redis instance is located.
- Regularly check the logs of Sentinel and Redis instances to monitor their status.
- Deploy sentinel instances on different servers to improve fault tolerance.
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