[HADOOP-9642] Configuration to resolve environment variables via ${env.VARIABLE} references

• Type: New Feature
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.1.0-beta, 3.0.0-alpha1
• Fix Version/s: 3.0.0-alpha1
• Component/s: conf, scripts
• Assignee: Kengo Seki
• Reporter: Steve Loughran
• Created: 13/Jun/13 08:26
• Updated: 11/Apr/21 10:50
• Resolved: 14/Apr/15 06:20

Description

We should be able to get env variables from Configuration files, rather than just system properties. I propose using the traditional env prefix ${env.PATH} to make it immediately clear to people reading a conf file that it's an env variable -and to avoid any confusion with system properties and existing configuration properties.

Issue Links

• is related to: HADOOP-17631 Configuration ${env.VAR:-FALLBACK} should eval FALLBACK when restrictSystemProps=true
• is related to: HADOOP-11553 Formalize the shell API