[HADOOP-10893] isolated classloader on the client side

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.0
• Fix Version/s: 2.6.0
• Component/s: util
• Hadoop Flags: Reviewed
• Assignee: Sangjin Lee
• Reporter: Sangjin Lee
• Created: 23/Jul/14 23:08
• Updated: 05/Mar/15 18:30
• Resolved: 21/Aug/14 21:41

Description

We have the job classloader on the mapreduce tasks that run on the cluster. It has a benefit of being able to isolate class space for user code and avoid version clashes.

Although it occurs less often, version clashes do occur on the client JVM. It would be good to introduce an isolated classloader on the client side as well to address this. A natural point to introduce this may be through RunJar, as that's how most of hadoop jobs are run.

Issue Links

• is related to: MAPREDUCE-1700 User supplied dependencies may conflict with MapReduce system JARs
• is related to: HADOOP-11656 Classpath isolation for downstream clients
• relates to: HADOOP-11048 user/custom LogManager fails to load if the client classloader is enabled
• relates to: HADOOP-11049 javax package system class default is too broad