[AMBARI-16412] Support TopN queries in AMS

• Type: Task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.2.2
• Fix Version/s: 2.4.0
• Component/s: ambari-metrics
• Assignee: Aravindan Vijayan
• Reporter: Aravindan Vijayan
• Created: 09/May/16 23:37
• Updated: 11/May/16 00:23
• Resolved: 10/May/16 21:32

Description

TopN is a useful feature in analyzing and finding the outlier in large clusters.

2 Use Cases where meant to be solved through this story.
Display the series for Top N hosts for a specific metric.
Display the Top N metrics (Users / HBase table metrics) for a given host or aggregated across all hosts

To facilitate the above, the following are supported.
> Top "N" hosts when 1 metric is requested for "H" hosts.
> Top "N" metrics when "M" metrics (or a pattern) are requested for 0 or 1 hosts.
> Default TopN Hosts when More than a specific value of hosts are requested. Default = 20. Configurable through ams-site config (timeline.metrics.default.topn.hosts.limit)

TopN API Example

http://<AMS_HOST>:6188/ws/v1/timeline/metrics?metricNames=cpu_system._avg&hostname=h1,h2,h3,h4,h5&appId=HOST&startTime=1462879340&endTime=1462900940&topN=2&topNFunction=avg&isBottomN=false

Added parameters
topN - Mandatory parameter for TopN query which denotes the number of series to be returned.
topNFunction - Optional parameter to specificy the comparator function for comparing 2 series while ordering. Default = max, Valid Values (max,avg,sum)
isBottomN - Optional parameter. If bottom N series are required instead of top N. Default = false.

Issue Links

• links to: Review Board