Node decommissioning and scaling in Hadoop - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start the decommissioning process for a node in Hadoop.

Hadoop

hdfs dfsadmin -[1] <node-hostname>

Drag options to blanks, or click blank then click option'

Adecommission

BrefreshNodes

CstartDecommission

DstopNode

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'decommission' instead of 'refreshNodes' flag.

Trying to decommission without updating the exclude file.

The command 'hdfs dfsadmin -refreshNodes' tells Hadoop to reload the list of nodes to decommission.

2fill in blank

medium

Complete the code to add a new node to the Hadoop cluster by updating the include file.

Hadoop

echo '[1]' >> /etc/hadoop/conf/dfs.include

Drag options to blanks, or click blank then click option'

Anew-node-hostname

Bnamenode-host

Cold-node-hostname

Ddatanode-host

Attempts:

3 left

💡 Hint

Common Mistakes

Adding the namenode hostname instead of the new node.

Editing the exclude file instead of the include file.

You add the new node's hostname to the dfs.include file to allow it to join the cluster.

3fill in blank

hard

Fix the error in the command to check the decommission status of nodes.

Hadoop

hdfs dfsadmin -[1]

Drag options to blanks, or click blank then click option'

Acheck

Bstatus

Creport

Dlist

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'status' or 'check' which are not valid dfsadmin flags.

Trying to list nodes with an incorrect flag.

The 'hdfs dfsadmin -report' command shows the status of all nodes including decommissioning progress.

4fill in blank

hard

Fill both blanks to update the exclude file and refresh nodes to decommission a node.

Hadoop

echo '[1]' >> /etc/hadoop/conf/dfs.exclude
hdfs dfsadmin -[2]

Drag options to blanks, or click blank then click option'

Anode-to-remove-hostname

BrefreshNodes

CdecommissionNode

DstopNode

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong flags like 'decommissionNode' instead of 'refreshNodes'.

Not updating the exclude file before refreshing nodes.

You add the node hostname to dfs.exclude and then run 'hdfs dfsadmin -refreshNodes' to start decommissioning.

5fill in blank

hard

Fill all three blanks to create a new node, add it to the include file, and refresh nodes to scale the cluster.

Hadoop

ssh [1] 'sudo systemctl start hadoop-datanode'
echo '[2]' >> /etc/hadoop/conf/dfs.include
hdfs dfsadmin -[3]

Drag options to blanks, or click blank then click option'

Anew-node-hostname

CrefreshNodes

DstartNode

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'startNode' instead of 'refreshNodes' to apply changes.

Not starting the datanode service before adding to include file.

You start the datanode service on the new node, add it to dfs.include, then refresh nodes to scale.