Entities & relationships examples via NRQL (E&R via NRQL)

Objective: An operations team needs to analyze CPU utilization for all production hosts located in a specific AWS region (e.g., 'eu-central-1') to identify potential performance bottlenecks.

Challenge: This often required exporting host data and performance metrics separately and then using external tools or complex scripts to join and analyze them.

NRQL solution:

FROM SystemSample
JOIN (FROM Entity SELECT id, name WHERE type = 'INFRA-HOST' AND `tags.aws.awsRegion` = 'eu-central-1')
ON entityGuid = id
SELECT average(cpuPercent) FACET name

Objective: A developer is investigating an incident that occurred several hours ago and needs to know the exact configuration or state of a specific host (or container, application, etc.) at that particular point in time.

Challenge: Obtaining a snapshot of an entity's attributes from a specific past timeframe was often not possible or required sifting through voluminous configuration logs, if available.

NRQL solution: This query retrieves all available attributes for a specific entity (identified by its id) within a narrow one-hour window from seven hours ago.

FROM Entity
SELECT *
WHERE id = '<your_entity_id>'
SINCE 7 hours ago UNTIL 6 hours ago
LIMIT 1

Objective: An SRE wants to understand how an entity's configuration or key attributes have changed over the last few hours, perhaps to see if a deployment or an automated process has altered its state as expected.

Challenge: Tracking subtle changes in an entity's state over time was difficult and often involved manual comparisons or custom monitoring scripts.

NRQL solution: This query fetches all recorded states for a particular entity within the last three hours, allowing for an audit of any changes.

SELECT *
  FROM Entity
  WHERE id = '<your_entity_id>'
  SINCE 3 hours ago

Objective: Identify the applications running on specific hosts

Challenge: Difficult to correlate applications to hosts

NRQL solution:

FROM EntityRelationship SELECT sourceEntityGuid, targetEntityGuid, sourceEntityType, targetEntityType, relationshipType   where (sourceEntityType like '%HOST%' and targetEntityType='APPLICATION') or (targetEntityType LIKE '%HOST%' and sourceEntityType='APPLICATION')