Connecting to both master and slave in a replicated Redis cluster

Question

I'm setting up a simple 1 Master - N Slaves Redis cluster (low write round, high read count). How to set this up is well documented on the Redis website, however, there is no information (or I missed it) about how the clients (Node.js servers in my case) handle the cluster. Do my servers need to have 2 Redis connections opened: one for the Master (writes) and one towards a Slave load-balancer for reads? Does the Redis driver handle this automatically and send reads to slaves and writes to the Master?

Answer 1

The only approach I found was using thunk-redis library. This library supports connecting to Redis master-slave without having a cluster configured or using a sentinel.

You just simply add multiple IP addresses to the client:

const client = redis.createClient(['127.0.0.1:6379', '127.0.0.1:6380'], {onlyMaster: false});

Answer 2

You don't need to specifically connect to particular instance, every instance in redis cluster has information of cluster. So even if you connect to one master, your client would to be connect to any instance in the cluster. So if you try to update a key present in different master(other than the one you connected), redis client takes care of it by using the redirection provided by the server.

To answer your second question, you can enable reads from slave by READONLY command