Node decommissioning and scaling in Hadoop - Mini Project: Build & Apply

Node Decommissioning and Scaling in Hadoop

📖 Scenario: You are managing a Hadoop cluster that processes large amounts of data daily. Sometimes, you need to remove (decommission) nodes safely without losing data or interrupting processing. Other times, you add new nodes to scale the cluster for better performance.Understanding how to decommission nodes and scale your cluster is essential to keep your data safe and your system efficient.

🎯 Goal: Learn how to mark nodes for decommissioning and how to update the cluster configuration to add new nodes for scaling.You will create a list of nodes, mark some for decommissioning, and then update the list to add new nodes.

📋 What You'll Learn

Create a list of current Hadoop cluster nodes

Create a list of nodes to decommission

Update the cluster nodes list by removing decommissioned nodes

Add new nodes to the cluster nodes list

Print the final list of active nodes

💡 Why This Matters

🌍 Real World

In real Hadoop clusters, administrators must safely remove nodes for maintenance or failure and add new nodes to handle more data. This project simulates managing node lists to keep the cluster healthy.

💼 Career

Understanding node decommissioning and scaling is crucial for Hadoop administrators and data engineers to maintain cluster performance and data integrity.

1

Create the initial list of Hadoop cluster nodes

Create a list called cluster_nodes with these exact node names: 'node1', 'node2', 'node3', 'node4', and 'node5'.

Hadoop

# Create the list of cluster nodes
# Your code here

Need a hint?

Use square brackets [] to create a list and separate node names with commas.

2

Create a list of nodes to decommission

Create a list called decommission_nodes with these exact node names: 'node2' and 'node4'.

Hadoop

cluster_nodes = ['node1', 'node2', 'node3', 'node4', 'node5']
# Create the list of nodes to decommission
# Your code here

Need a hint?

Use a list to hold the nodes you want to remove from the cluster.

3

Remove decommissioned nodes from the cluster

Create a new list called active_nodes that contains all nodes from cluster_nodes except those in decommission_nodes. Use a list comprehension with node as the iterator variable.

Hadoop

cluster_nodes = ['node1', 'node2', 'node3', 'node4', 'node5']
decommission_nodes = ['node2', 'node4']
# Create active_nodes list excluding decommission_nodes
# Your code here

Need a hint?

Use a list comprehension to filter out nodes that are in the decommission list.

4

Add new nodes and print the final active nodes list

Add the new nodes 'node6' and 'node7' to the active_nodes list using the extend() method. Then print the active_nodes list.

Hadoop

cluster_nodes = ['node1', 'node2', 'node3', 'node4', 'node5']
decommission_nodes = ['node2', 'node4']
active_nodes = [node for node in cluster_nodes if node not in decommission_nodes]
# Add new nodes and print active_nodes
# Your code here

Need a hint?

Use extend() to add multiple items to a list, then use print() to show the final list.