[HADOOP-5175] Option to prohibit jars unpacking

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.19.0
• Fix Version/s: 0.21.0

Environment

Hadoop cluster of 5 servers, each with:
HDD: two disks WDC WD1000FYPS-01ZKB0
OS: Linux 2.6.26-1-686 #1 SMP
FS: XFS

• Hadoop Flags: Reviewed
• Release Note: Jars passed to the -libjars option of hadoop jars are no longer unpacked inside mapred.local.dir.
• Assignee: Todd Lipcon
• Reporter: Andrei Gudkov
• Created: 05/Feb/09 15:57
• Updated: 24/Aug/10 20:35
• Resolved: 27/May/09 11:01

Description

I've noticed that task tracker moves all unpacked jars into
${hadoop.tmp.dir}/mapred/local/taskTracker.

We are using a lot of external libraries, that are deployed via "-libjars"
option. The total number of files after unpacking is about 20 thousands.

After running a number of jobs, tasks start to be killed with timeout reason
("Task attempt_200901281518_0011_m_000173_2 failed to report status for 601
seconds. Killing!"). All killed tasks are in "initializing" state. I've
watched the tasktracker logs and found such messages:

Thread 20926 (Thread-10368):
State: BLOCKED
Blocked count: 3611
Waited count: 24
Blocked on java.lang.ref.Reference$Lock@e48ed6
Blocked by 20882 (Thread-10341)
Stack:
java.lang.StringCoding$StringEncoder.encode(StringCoding.java:232)
java.lang.StringCoding.encode(StringCoding.java:272)
java.lang.String.getBytes(String.java:947)
java.io.UnixFileSystem.getBooleanAttributes0(Native Method)
java.io.UnixFileSystem.getBooleanAttributes(UnixFileSystem.java:228)
java.io.File.isDirectory(File.java:754)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:427)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:433)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:433)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:433)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:433)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:433)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:433)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:433)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:433)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:433)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:433)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:433)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:433)
org.apache.hadoop.fs.FileUtil.getDU(FileUtil.java:433)

HADOOP-4780 patch brings the code which stores map of directories along
with their DU's, thus reducing the number of calls to DU. However, the delete operation takes too long. I've manually deleted archive after 10 jobs had run and it took over 30 minutes on XFS.

I suppose that an option to prohibit jars unpacking would be helpfull in my situation.