[HADOOP-1179] task Tracker should be restarted if its jetty http server cannot serve get-map-output files

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.12.3
• Assignee: Devaraj Das
• Reporter: Runping Qi
• Created: 28/Mar/07 22:08
• Updated: 06/Apr/07 16:54
• Resolved: 04/Apr/07 12:14

Description

Due to some errors (mem leak?), the jetty http server throws outOfMemory exception when serving get-map-output requests:

2007-03-28 20:42:39,608 WARN org.mortbay.jetty.servlet.ServletHandler: Error for
/mapOutput?map=task_0334_m_013127_0&reduce=591
2007-03-28 20:46:42,788 WARN org.mortbay.jetty.servlet.ServletHandler: Error for
/mapOutput?map=task_0334_m_013127_0&reduce=591
2007-03-28 20:49:38,064 WARN org.mortbay.jetty.servlet.ServletHandler: Error for
java.lang.OutOfMemoryError
at java.io.FileInputStream.readBytes(Native Method)
at java.io.FileInputStream.read(FileInputStream.java:199)
at org.apache.hadoop.fs.RawLocalFileSystem$LocalFSFileInputStream.read(R
awLocalFileSystem.java:119)
at org.apache.hadoop.fs.FSDataInputStream$PositionCache.read(FSDataInput
Stream.java:41)
at java.io.BufferedInputStream.read1(BufferedInputStream.java:256)
at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
at java.io.DataInputStream.read(DataInputStream.java:132)
at org.apache.hadoop.fs.ChecksumFileSystem$FSInputChecker.readBuffer(Che
cksumFileSystem.java:182)
at org.apache.hadoop.fs.ChecksumFileSystem$FSInputChecker.read(ChecksumF
ileSystem.java:167)
at org.apache.hadoop.fs.FSDataInputStream$PositionCache.read(FSDataInput
Stream.java:41)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
at java.io.BufferedInputStream.read1(BufferedInputStream.java:258)
at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
at java.io.DataInputStream.readFully(DataInputStream.java:178)
at java.io.DataInputStream.readLong(DataInputStream.java:399)
at org.apache.hadoop.mapred.TaskTracker$MapOutputServlet.doGet(TaskTrack
er.java:1643)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:427
)
at org.mortbay.jetty.servlet.WebApplicationHandler.dispatch(WebApplicati
onHandler.java:475)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:5
67)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1565)
at org.mortbay.jetty.servlet.WebApplicationContext.handle(WebApplication
Context.java:635)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1517)
at org.mortbay.http.HttpServer.service(HttpServer.java:954)
at org.mortbay.http.HttpConnection.service(HttpConnection.java:814)
at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:981)
at org.mortbay.http.HttpConnection.handle(HttpConnection.java:831)
at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:
244)
at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:357)
at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)

In this case, the task tracker cannot send out the map outut files on that machine, rendering it useless.
Moreover, all the reduces depending on those map output files are just stuck there.
If the task tracker reports fail to the job tracker, the map/reduce job can recover.
If the task tracker restarted, it can continue to join the cluster as a new mamber.