Redis学习总结第五章--Redis集群选举原理分析

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最新推荐文章于 2025-04-24 11:51:46 发布 · 448 阅读

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当Redis主节点进入FAIL状态，其从节点会发起选举。从节点需满足：主节点失败、主节点有槽位、与主节点断连不超过一定时间。从节点通过向其他主节点请求投票，多数同意后晋升为主节点。选举过程中，节点会计算延迟以避免同时选举，确保集群稳定。

Redis学习总结第五章--Redis集群选举原理分析

参考文章：https://redis.io/topics/cluster-spec

Slave election and promotion

Slave election and promotion is handled by slave nodes, with the help of master nodes that vote for the slave to promote. A slave election happens when a master is in FAIL state from the point of view of at least one of its slaves that has the prerequisites in order to become a master.

In order for a slave to promote itself to master, it needs to start an election and win it. All the slaves for a given master can start an election if the master is in FAIL state, however only one slave will win the election and promote itself to master.

A slave starts an election when the following conditions are met:

The slave's master is in FAIL state.
The master was serving a non-zero number of slots.
The slave replication link was disconnected from the master for no longer than a given amount of time, in order to ensure the promoted slave's data is reasonably fresh. This time is user configurable.

In or