(of course, if you suspend the datanode daemon for a long time, the cluster might treated it as a dead node ^_^ for me)
maybe there is some options in the config files that can make the time longer?any suggestion? 2010/9/15 xu cheng <[email protected]> > hello: > thanks for replying! > I'm not sure which specific area I'm interested in. I just wanna to > understand how the wonderful system works. and triggling break point in the > source code and watch the state of the system might be a useful way to do > that(or I might be wrong ^_^ ). > I've found that remote debugging with the JDWP protocal in Eclipse IDEmight > work. > for an example, If I wanna debug the datanode, I can set the last line > of the HADOOP_HOME/hdfs/bin/hdfs.sh > exec "$JAVA" $JAVA_HEAP_MAX $HADOOP_OPTS $CLASS "$@" > > to like this: > > exec "$JAVA" -Xdebug -Xrunjdwp:transport=dt_socket,address=9999 > ,server=y,suspend=y $JAVA_HEAP_MAX $HADOOP_OPTS $CLASS "$@" > > and then in the eclipse IDE (of course ,with the source code of the hadoop > imported ^_^ ) click run->debug configurations > ->remote java application. set the ip(or the name if the hosts file is > set) to the machine that running the datanode daemon you wanna debug and the > port which is 9999 that I set before. > then apply and debug. > > ok,if you don't set any breakpoints ,then the system will work normally,and > once any breakpoints are set, the daemon will be > suspended, and you can watch anything at this point(of course, if you > suspend the datanode daemon for a long time, the cluster might treated it as > a dead node ^_^ for me) > > I've wrote more specific words on this(but in Chineses ^_^)anyone > interested in it ,just let me know). > and thanks for your suggestion, I will read the documents you suggested to > see an easy way > > thanks again. > > xu > > 2010/9/15 Arun C Murthy <[email protected]> > > Xu, >> >> Welcome! >> >> Is there a specific area you are interested in? If so we can point you to >> relevant classes etc. In fact, as you understand them I'd encourage you to >> start documenting them to help others too. >> >> One way to start is to take up simpler jiras, in the beginning, and start >> fixing them: >> https://issues.apache.org/jira/browse/MAPREDUCE >> >> Also look at the 'Developer Documentation' section in the hadoop wiki: >> http://wiki.apache.org/hadoop/. >> This link might be useful http://wiki.apache.org/hadoop/HowToContribute. >> >> Arun >> >> >> On Sep 14, 2010, at 8:02 PM, xu cheng wrote: >> >> hello: >>> I've learn hadoop for some time, and I'm interesting in the >>> implementation >>> of the mapreduce framework of the Hadoop project. I think reading the >>> mapreduce framework source code would be a good way to do that and >>> debugging >>> the system to see how everything works would make this progress better. >>> however I have no experience debugging distributed system. and I have no >>> idea on how to debug the mapreduce framework source code. so could you >>> please help me? >>> any suggestion or reference would be appreciated! ^_^ thanks >>> >> >> >
