[SPARK-745] Document Scala environment configuration when Scala is installed from RPM

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.7.3, 0.8.0
• Component/s: Documentation
• Assignee: Matei Alexandru Zaharia
• Reporter: Josh Rosen
• Created: 07/May/13 18:20
• Updated: 30/Jun/13 17:14
• Resolved: 30/Jun/13 17:14

Description

As https://github.com/mesos/spark/pull/292 points out, the Typesafe Scala RPM installs the scala executable in /usr/bin/ and places the Scala library JARs in /usr/share/java/.

That pull request added a SCALA_LIBRARY_PATH setting to support this method of installing Scala.

We should document proper configuration of SCALA_LIBRARY_PATH and SCALA_HOME; right now, that pull request is the only documentation and it's implicit that the proper Debian / CentOS settings are SCALA_HOME=/usr/ and SCALA_LIBRARY_PATH=/usr/share/java/.

I propose adding extra comments to the spark-conf.sh template that describe typical values for these settings. Maybe we also want to mention this in the docs somewhere?