for the nmap fans give the hadoop-jobtracker-info script from the below link ago ;)
https://github.com/b4ldr/nse-scripts disclaimer: this email is about shameless, self promotion On 11 October 2011 19:52, patrick sang <[email protected]> wrote: > for cli fans, > > In DFS side - ./bin/hadoop dfsadmin -report > In MR side - ./bin/hadoop job -list-active-trackers > > hth, > P > > On Tue, Oct 11, 2011 at 5:27 AM, Uma Maheswara Rao G 72686 < > [email protected]> wrote: > >> Hello Raimon, >> >> In DFS to know the DN status you can use getDataNodeStats API from >> Distributed fileSystem. >> >> In MR, to know the number of active trackers, you can use getClusterStatus >> from jobclient. It will give other stats as well. >> >> Hope this will help. >> >> Regards, >> Uma >> >> >> ----- Original Message ----- >> From: Raimon Bosch <[email protected]> >> Date: Tuesday, October 11, 2011 5:48 pm >> Subject: How to get number of live nodes in hadoop >> To: [email protected] >> >> > Hi, >> > >> > Following this instructions at >> > http://wiki.apache.org/hadoop/HowManyMapsAndReduces I've read that >> > the best >> > amount of reducers for one process is 0.95 or 1.75 * (nodes * >> > mapred.tasktracker.tasks.maximum) so I would like to call >> > to conf.setNumReduceTasks(int num) according to how many nodes I have >> > working. >> > >> > So how can I get the number of live nodes from my hadoop code? >> > >> > Thanks in advance, >> > Raimon Bosch. >> > >> >
