Question: How can you set up a Redis cluster with 2 nodes?

Answer

Setting up a Redis cluster with two nodes involves the following steps:

1. Install Redis: You need to install Redis on each node. Use your OS package manager, or download and compile Redis from source.

wget http://download.redis.io/redis-stable.tar.gz
tar xvzf redis-stable.tar.gz
cd redis-stable
make

2. Configure each Redis instance for clustering: Modify the redis.conf file for each instance. Set the cluster-enabled option to yes, specify a cluster-config-file, and provide a cluster-node-timeout.

# redis.conf
cluster-enabled yes
cluster-config-file nodes.conf
cluster-node-timeout 5000
appendonly yes

3. Start the Redis instances: Start each Redis instance using their specific redis.conf files.

src/redis-server /path/to/redis.conf

4. Create the Cluster: Use the redis-cli utility to create the cluster. Consider the IP addresses are 192.168.1.1 and 192.168.1.2 and they are both running Redis on port 7000.

redis-cli --cluster create 192.168.1.1:7000 192.168.1.2:7000

5. Follow the prompts: The redis-cli utility will propose a configuration. Accept it.

Please note that Redis cluster requires at least three master nodes for robust failover and distributed storage. A cluster with only two nodes does not guarantee high availability. It's better to use a setup with at least three nodes if you want high availability and partition tolerance.