[MAPREDUCE-2061] child environment substitution is broken

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Assignee: Unassigned
• Reporter: Hong Tang
• Created: 11/Sep/10 01:16
• Updated: 30/Jul/14 23:56
• Resolved: 30/Jul/14 23:56

Description

TaskRunner.getVMEnvironment is still broken in a couple of ways even after HADOOP-5981:

• It does not recognize ${VAR} notation. This is necessary if we have both "VAR" and "VAR_1" existent, and it becomes ambiguous whether $VAR_1 means appending _1 following $VAR, or simply taking the value of $VAR_1
• It tries to do lazy-binding except for self-referencing like X=$X:Y. This would cause some unexpected behavior. For instance, if I specify "A=$LD_LIBRARY_PATH:xxx", A would be shown as ":xxx", while if I specify "LD_LIBRARY_PATH=$Z:xxx,Z=$LD_LIBRARY_PATH:yyy", Z would be come the actual value of LD_LIBRARY_PATH + ":yyy" (and LD_LIBRARY_PATH is not affected at all). I think we should support eager binding (and we can support lazy binding later through quoting or escaping).

Issue Links

• Is contained by: MAPREDUCE-6491 Environment variable handling assumes values should be appended