+1 for Chris, remote debug will help you. On Tue, Dec 22, 2015 at 1:54 AM, Chris Nauroth <[email protected]> wrote:
> If you're running the Hadoop daemons in pseudo-distributed mode (all the > daemons running as separate processes, but on a single dev host), then > another option is to launch the daemon's JVM with the JDWP arguments and > attach a "remote" debugger. This can be either the jdb CLI debugger that > ships with the JDK or a fancier IDE like Eclipse or IntelliJ. > > Each daemon's JVM arguments are controlled with an environment variable > suffixed with "_OPTS" defined in files named *-env.sh. For example, in > hadoop-env.sh, you could set something like this to enable remote > debugging for the NameNode process: > > export > HADOOP_NAMENODE_OPTS="-agentlib:jdwp=transport=dt_socket,server=y,address=8 > 000,suspend=n $HADOOP_NAMENODE_OPTS" > > > Then, you can run "jdb -attach localhost:8000" to attach the debugger, or > do the equivalent in your IDE of choice. > > --Chris Nauroth > > > > > On 12/21/15, 7:25 AM, "Daniel Templeton" <[email protected]> wrote: > > >Your best bet is to find a test that includes all the bits you want and > >execute that test in debug mode. (You can also change an existing test > >to include what you want, but in most cases it is easier to start with > >an existing test than to start from scratch.) > > > >Daniel > > > >On 12/20/15 6:01 PM, Allen Zhang wrote: > >> Hi all, > >> > >> I am reading hadoop-2.6.0 source code, mainly focusing on hadoop yarn. > >> However i have some problems in reading or debugging the source > >>code,can I debug it locally(I mean in my laptop locally with this source > >>code I've downloaded, not remotely debug), > >> because I need to track it execution flow stey by stey, and then I want > >>to add a new feature or enhancement. > >> > >> > >> So can anyone give some good suggestions or share your method or any > >>wiki page? Really appreciate!! > >> > >> > >> Thanks, > >> Allen > > > > > > -- Best Regards Jeff Zhang
