Map reduce Query

Can we take input in a mapper function and in some way pass it to reducer ? Regards,

hdfs 2.2 federation

ns01 = HA( namenode194-active, namenode195-standby ) ns02 = HA( namenode196-active, namenode197-standby ) I was running on the server command 195 I was running the command(-safemode enter) namenode194 server $HADOOP_PREFIX/bin/hdfs dfsadmin -safemode enter I was expecting to change saf

Re: Map reduce Query

This is what we do. I'm sorry I didn't quite this. We read in the data through Mapper, do some operations on it, and pass the Mapper output on to the Reducer. If you intend to just pass the data as it is then just context.write it without doing anything else. *Warm regards,* *Mohammad Tariq* *clo

Re: Map reduce Query

That’s exactly what MapReduce does. The input is processed by the mapper function, and its output will be automatically sent into the reducer function. Between mappers and reducers we have the automatic shuffle phase which sends records with identical keys into one reducer call. If you want to

Re: Map reduce Query

you can get the input from some source(e.g. files) in the mapper setup() method and emit it to the context.write() so that it can reach to the reducer. Raj K Singh http://in.linkedin.com/in/rajkrrsingh http://www.rajkrrsingh.blogspot.com Mobile Tel: +91 (0

RE: HDFS File Writes & Reads

What your understanding is almost correct, but not with the part your highlighted. The HDFS is not designed for write performance, but the client doesn't have to wait for the acknowledgment of previous packets before sending the next packets. This webpage describes it clearly, and hope it is help

Hadoop 2.4 Fair Scheduler goes missing

All, I recently upgraded to Hadoop 2.4 and I am seeing a problem with the Resource Manager's fair scheduler. After a couple days of full time operation where several MR jobs are submitted per minute, the fair scheduler will suddenly stop scheduling jobs. The only way I have found to remedy this

Re: hdfs 2.2 federation

Hi, There are some open issues with DFSAdmin. You can read more at https://issues.apache.org/jira/browse/HDFS-5147 (Certain dfsadmin commands such as safemode do not interact with the active namenode in ha setup) https://issues.apache.org/jira/browse/HDFS-6507 (Improve DFSAdmin to support HA clu

Fwd: Hadoop 2.x -- how to configure secondary namenode?

I confirmed, Hadoop 2 does use $HADOOP_CONF_DIR/masters to start secondary namenodes. -- Forwarded message -- From: craig w Date: Wed, Jun 18, 2014 at 2:12 PM Subject: Hadoop 2.x -- how to configure secondary namenode? To: user@hadoop.apache.org I have an old Hadoop install that

Deploying Hadoop 2.x test cluster with Juju in minutes (local LXC)

Hi all, My name is Amir Sanjar, team lead at Canonical Big Data Solution Center. For those of us who had the luxury of deploying hadoop across any types of clusters, bare-metal or cloud, are well aware it is a science that could consume precious many happy hour time :). Few weeks ago, I finally bow

Re: Unsatisfied link error

Could somebody suggest what might be wrong here? On Wed, Jun 18, 2014 at 5:37 PM, Mohit Anchlia wrote: > I installed hadoop and now when I try to run "hadoop fs" I get this error. > I am using openjdk 64 bit on a virtual machine on a centos vm. I am also > listing my environment variable and one

elasticsearch mapreduce example?

could anyone points me to a mapreduced example that uses elasticsearch-hadoop.jar to communicate with elasticsearch cluster? Thanks

Re: HDFS File Writes & Reads

Yong, Thanks for the clarification. It was more of an academic query. We do not have any performance requirements at this stage. Regards Vijay On 19 June 2014 19:05, java8964 wrote: > What your understanding is almost correct, but not with the part your > highlighted. > > The HDFS is not desi

Map reduce query

How can I give Input to a mapper from the command line? -D option can be used but what are the corresponding changes required in the mapper and the driver program ? Regards,