Why cluster administration ensures reliability in Hadoop - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start the Hadoop cluster service.

Hadoop

sudo service hadoop-[1] start

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

Anamenode

Bdatanode

Cresourcemanager

Dnodemanager

Attempts:

3 left

💡 Hint

Common Mistakes

Starting datanode first instead of namenode

Confusing resource manager with namenode

The namenode service manages the metadata and is essential to start first for cluster reliability.

2fill in blank

medium

Complete the code to check the status of the DataNode service.

Hadoop

hdfs dfsadmin -report | grep [1]

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

ANameNode

BDataNode

CResourceManager

DNodeManager

Attempts:

3 left

💡 Hint

Common Mistakes

Using NameNode instead of DataNode in grep

Confusing ResourceManager with DataNode

The command filters the report to show information about DataNode services, which store actual data blocks.

3fill in blank

hard

Fix the error in the command to restart the ResourceManager service.

Hadoop

sudo service hadoop-[1] restart

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

Anodemanager

Bnamenode

Cdatanode

Dresourcemanager

Attempts:

3 left

💡 Hint

Common Mistakes

Restarting namenode instead of resourcemanager

Using datanode or nodemanager incorrectly

The resourcemanager manages cluster resources and restarting it helps maintain cluster reliability.

4fill in blank

hard

Fill both blanks to create a dictionary of node statuses where keys are node names and values are their {{BLANK_1}} if they {{BLANK_2}} the cluster.

Hadoop

node_status = {node: status for node, status in nodes.items() if status [1] 'active' and node [2] cluster_nodes}

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A==

Bin

C!=

Dnot in

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' instead of '==' for status check

Using 'not in' instead of 'in' for node membership

The code filters nodes with status equal to 'active' and nodes that are in the cluster_nodes list to ensure reliability.

5fill in blank

hard

Fill all three blanks to create a dictionary of node loads where keys are node names in uppercase, values are their load if load {{BLANK_1}} threshold and node {{BLANK_2}} active_nodes and status {{BLANK_3}} 'active'.

Hadoop

node_loads = {node[1]: load for node, (load, status) in node_info.items() if load [2] threshold and node [3] active_nodes and status == 'active'}

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

A.upper()

B<

Cin

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' instead of '<' for load comparison

Using 'not in' instead of 'in' for active_nodes membership

Forgetting to uppercase node names

The dictionary comprehension converts node names to uppercase, filters loads less than the threshold, and includes only nodes in active_nodes with status 'active' to ensure cluster reliability.