Explain Redis Sentinel for high availability setup.

Redis Sentinel provides high availability and monitoring: **Architecture:** • Monitors master and replica instances • Automatic failover when master fails • Configuration provider for clients • Notification system for events **Sentinel Configuration:** # sentinel.conf port 26379 sentinel monitor mymaster 192.168.1.100 6379 2 sentinel auth-pass mymaster your_password sentinel down-after-milliseconds mymaster 5000 sentinel failover-timeout mymaster 10000 sentinel parallel-syncs mymaster 1 **Client Connection (Python):** from redis.sentinel import Sentinel # Connect to Sentinels sentinel = Sentinel([ ('192.168.1.100', 26379), ('192.168.1.101', 26379), ('192.168.1.102', 26379) ], socket_timeout=0.1) # Get master and replica connections master = sentinel.master_for('mymaster', socket_timeout=0.1) replica = sentinel.slave_for('mymaster', socket_timeout=0.1) # Use connections master.set('key', 'value') # Write to master value = replica.get('key') # Read from replica **Monitoring Commands:** # Sentinel status redis-cli -p 26379 SENTINEL masters redis-cli -p 26379 SENTINEL slaves mymaster # Manual failover redis-cli -p 26379 SENTINEL failover mymaster **Best Practices:** • Deploy odd number of Sentinels (3, 5, 7) • Distribute Sentinels across different servers • Set appropriate timeouts • Monitor Sentinel logs • Test failover scenarios regularly