All 7 Clustering questions
More in Clustering
What is Redis Cluster, and what problem does it solve compared to running a single Redis instance? What is the difference between a master node and a replica node within a Redis Cluster? What are the key limitations of Redis Cluster that developers should be aware of compared to a single instance Redis setup? How do you monitor the overall health and status of a Redis Cluster to catch problems before they affect your application? How would you design a Redis Cluster deployment to properly balance high availability, performance, and cost for a large scale production application? What is a split brain scenario in the context of Redis Cluster, and how does the cluster protect against it?
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Redis › Clustering

How does Redis Cluster automatically handle failover when a master node becomes unavailable?

Intermediate

Answer

When enough nodes in the cluster agree that a specific master has become unreachable, one of that master's replicas is automatically promoted to become the new master, taking over responsibility for that master's hash slots, allowing the cluster to continue operating without manual intervention.
-- Failover happens automatically once a majority
-- of master nodes agree the original master is down
redis-cli cluster nodes
Real-world example A retail company's Redis Cluster automatically promotes a replica to master status within seconds after the original master node crashes during a hardware failure, keeping their shopping cart service running with minimal disruption.

Common follow-ups: How long does automatic failover typically take to complete?;What happens to write requests that were in progress during the failover?

Redis Sentinel & High Availability;Cluster Sharding & Hash Slots
All 7 Clustering questions