How to configure Spring redis sentinel in kubernetes

Question

I have a redis sentinel master slave setup with 1 master and 3 slaves and this is in Kubernetes environment.In the spring lettuce configuration, I have to specify the sentinels URLs with port numbers. How should I specify the URL for each sentinel? Spring doc specifies IP and port. In the local it's ok but when in k8s, how should I configure? I installed the set up with bitnami redis chart. Below is how it's done locally.

   @Bean
public RedisConnectionFactory lettuceConnectionFactory() {
  RedisSentinelConfiguration sentinelConfig = new RedisSentinelConfiguration()
  .master("mymaster")
  .sentinel("127.0.0.1", 26379)
  .sentinel("127.0.0.1", 26380);
  return new LettuceConnectionFactory(sentinelConfig);
}

Thanks

user13424620 user13424620 · Accepted Answer · 2020-05-06T16:00:42

First thing -> using the bitnami helm chart is the right way to do things.

Although a bit of a different implementation, heres how we implemented the same master slave setup AND also avoided the above problem while ensuring the MAXIMUM availability we ever witnessed (less than 2 secs Downtime for master)

We made two services - one for master and another for slaves.
a PV PVC that was shared between the slaves and master where ONLY Master would write and slaves would only read from PV
this way we could always ensure that there was 1 pod running ALL time for master and N replicas behind the headless service for slaves.

In application slaves and master URL's would always be different, thus ensuring a clear "WRITE" and "READ" isolation and improving the stability of system with almost no failures for reads.

How to configure Spring redis sentinel in kubernetes

2 Answers