Adding and removing nodes in Redis - Mini Project: Build & Apply

Adding and Removing Nodes in Redis Cluster

📖 Scenario: You are managing a Redis cluster for a growing online store. The cluster needs to be updated by adding a new node to handle more traffic and removing an old node that is no longer needed.

🎯 Goal: Learn how to add a new node to a Redis cluster and remove an existing node using Redis CLI commands.

📋 What You'll Learn

Create a Redis cluster with three nodes

Add a new node to the existing cluster

Remove an existing node from the cluster

Verify the cluster nodes after each operation

💡 Why This Matters

🌍 Real World

Managing Redis clusters is essential for scaling applications that require fast data access and high availability.

💼 Career

Database administrators and backend engineers often need to add or remove nodes in Redis clusters to maintain performance and reliability.

1

Create a Redis cluster with three nodes

Use the Redis CLI command redis-cli --cluster create with the exact node addresses 127.0.0.1:7000, 127.0.0.1:7001, and 127.0.0.1:7002 to create a cluster. Include the --cluster-replicas 0 option to create no replicas.

Redis

# Your command here to create the cluster with nodes 127.0.0.1:7000, 7001, 7002

Need a hint?

Use redis-cli --cluster create followed by the three node addresses and --cluster-replicas 0.

2

Add a new node to the existing cluster

Use the Redis CLI command redis-cli --cluster add-node to add the new node 127.0.0.1:7003 to the cluster. Specify the existing cluster node 127.0.0.1:7000 as the target for the join.

Redis

redis-cli --cluster create 127.0.0.1:7000 127.0.0.1:7001 127.0.0.1:7002 --cluster-replicas 0
# Your command here to add node 127.0.0.1:7003 to the cluster

Need a hint?

Use redis-cli --cluster add-node 127.0.0.1:7003 127.0.0.1:7000 to add the new node.

3

Remove an existing node from the cluster

Use the Redis CLI command redis-cli --cluster del-node to remove the node 127.0.0.1:7001 from the cluster. You need to specify the cluster node 127.0.0.1:7000 and the node ID of 127.0.0.1:7001. For this exercise, use the placeholder node ID node-id-7001 exactly as shown.

Redis

redis-cli --cluster create 127.0.0.1:7000 127.0.0.1:7001 127.0.0.1:7002 --cluster-replicas 0
redis-cli --cluster add-node 127.0.0.1:7003 127.0.0.1:7000
# Your command here to remove node 127.0.0.1:7001 using node ID node-id-7001

Need a hint?

Use redis-cli --cluster del-node 127.0.0.1:7000 node-id-7001 to remove the node.

4

Verify the cluster nodes after changes

Use the Redis CLI command redis-cli --cluster nodes with the cluster node 127.0.0.1:7000 to list all nodes currently in the cluster.

Redis

redis-cli --cluster create 127.0.0.1:7000 127.0.0.1:7001 127.0.0.1:7002 --cluster-replicas 0
redis-cli --cluster add-node 127.0.0.1:7003 127.0.0.1:7000
redis-cli --cluster del-node 127.0.0.1:7000 node-id-7001
# Your command here to list cluster nodes

Need a hint?

Use redis-cli --cluster nodes 127.0.0.1:7000 to see the current cluster nodes.