[HADOOP-13628] Support to retrieve specific property from configuration via REST API

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.7.3
• Fix Version/s: 2.9.0, 3.0.0-alpha2, 2.8.3
• Component/s: conf
• Hadoop Flags: Reviewed
• Assignee: Weiwei Yang
• Reporter: Weiwei Yang
• Created: 20/Sep/16 16:35
• Updated: 11/Aug/17 18:14
• Resolved: 05/Oct/16 20:55

Description

Currently we can use rest API to retrieve all configuration properties per daemon, but unable to get a specific property by name. This causes extra parse work at client side when dealing with Hadoop configurations, and also it's quite over head to send all configuration in a http response over network. Propose to support following a name parameter in the http request, by issuing

curl --header "Accept:application/json" http://${RM_HOST}/conf?name=yarn.nodemanager.aux-services

get output

{"property"{"key":"yarn.resourcemanager.hostname","value":"${RM_HOST}","isFinal":false,"resource":"yarn-site.xml"}}

This change is fully backwards compatible.