Why cluster health ensures reliability in Elasticsearch - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check the cluster health status.

Elasticsearch

GET /_cluster/health?wait_for_status=[1]

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

A"green"

B"blue"

C"red"

D"yellow"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'red' or 'yellow' which indicate problems in the cluster.

The wait_for_status parameter waits until the cluster reaches the green status, which means all primary and replica shards are active, ensuring reliability.

2fill in blank

medium

Complete the code to retrieve the number of active primary shards.

Elasticsearch

GET /_cluster/health?filter_path=[1]

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

A"number_of_nodes"

B"status"

C"active_primary_shards"

D"relocating_shards"

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing with status or number_of_nodes fields.

The active_primary_shards field shows how many primary shards are active, which is important for data reliability.

3fill in blank

hard

Fix the error in the code to wait for the cluster to be at least yellow.

Elasticsearch

GET /_cluster/health?wait_for_status=[1]

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

A"green"

B"yellow"

C"red"

D"blue"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'red' which means cluster is unhealthy.

Waiting for yellow status ensures all primary shards are active, which is a minimum for reliability, even if some replicas are not allocated.

4fill in blank

hard

Fill both blanks to filter the cluster health response to only show status and number of nodes.

Elasticsearch

GET /_cluster/health?filter_path=[1],[2]

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

A"status"

B"number_of_nodes"

C"active_shards"

D"relocating_shards"

Attempts:

3 left

💡 Hint

Common Mistakes

Including shard counts which are not asked for.

The filter_path parameter limits the response to only the status and number_of_nodes fields, helping focus on cluster health and size.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps node names to their roles if the cluster status is green.

Elasticsearch

nodes_roles = {node['name']: node['roles'] for node in cluster['nodes'] if cluster['status'] == [1] and 'data' [2] node['roles'] and 'master' [3] node['roles']}

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

A"green"

Bin

Cnot in

D"yellow"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'not in' which excludes nodes with those roles.

This comprehension selects nodes only if the cluster is green and the node has both 'data' and 'master' roles, ensuring reliability by focusing on active nodes.