in some cases, u have to debug it in a real cluster (for example a production problem)
in that case you need to specify the -Xdebug -Xrunjdwp:transport=dt_socket,address=12345,server=n,suspend=n for mapred.java.child.opts for the job (sorry forgot the exact param name, maybe not exactly mapred.java.child.opts) then use eclipse to connect to the tasktracker , note you need to choose between "Listen/attach" in the "Run remote application" window in eclipse On Wed, Jul 4, 2012 at 7:00 PM, Jason Yang <lin.yang.ja...@gmail.com> wrote: > ramon, > > Thank for your reply very much. > > However, I was still wonder whether I could debug a MR application in this > way. > > I have read some posts talking about using NAT to redirect all the packets > to the network card which connect to the local LAN, but it does not work as > I tried to redirect by using iptables :( > > 在 2012年7月4日星期三， 写道： > >> Jason, >> >> >> the easiest way to debug a MapRedupe program with eclipse is working >> on hadoop local. >> http://hadoop.apache.org/common/docs/r0.20.2/quickstart.html#Local In >> this mode all the components run locally on the same VM and can be easily >> debugged using Eclipse. Hope this will be useful. >> >> >> >> *From:* Jason Yang [mailto:lin.yang.ja...@gmail.com] >> *Sent:* miércoles, 04 de julio de 2012 11:25 >> *To:* mapreduce-user >> *Subject:* How to connect to a cluster by using eclipse >> >> >> >> Hi, all >> >> >> >> I have a hadoop cluster with 3 nodes, the network topology is like this: >> >> 1. For each DataNode, its IP address is like :192.168.0.XXX; >> >> 2. For the NameNode, it has two network cards: one is connect with the >> DataNodes as a local LAN with IP address 192.168.0.110, while the other one >> is connect to the company network(which eventually connect to the Internet); >> >> -- >> >> now I'm trying to debug a MapReduce program on a computer which is in the >> company network. Since the jobtracker in this scenario is >> 192.168.0.110:9001, I was wondering how could I connect to the cluster >> by using eclipse? >> >> >> >> -- >> >> YANG, Lin >> >> >> >> ------------------------------ >> Subject to local law, communications with Accenture and its affiliates >> including telephone calls and emails (including content), may be monitored >> by our systems for the purposes of security and the assessment of internal >> compliance with Accenture policy. >> >> ______________________________________________________________________________________ >> >> www.accenture.com >> > > > -- > YANG, Lin > >
