zero running map tasks and running reduce task in UI

[Taniya Tom]

Hi,

I am a hadoop student from Udemy. I followed all the instructions for hadoop installation without much trouble. In the end. I ran  " bin/hadoop jar hadoop-examples-*.jar grep input output 'dfs[a-z.]+' " to test hadoop. But I see 0 'running map task' and 0 'running reduce tasks in the UI from browser. Attaching the screen shot as well.

Is there a problem with my installation? Or is it ok to have zero value for these parameters? Please help me.

Thanks,

Taniya

[Nitesh Jain]

Hi Taniya,

The installation process is a little tricky. Could you please let me know of the following so that I can better understand the problem?

1. Output of command: 

jps

2, Output/error message when you typed in the command 

bin/hadoop jar hadoop-examples-*.jar grep input output 'dfs[a-z.]+

Best,

Nitesh 

Hadoop-Skills.com

[Taniya Tom]

Thank you for the quick response Nitesh. 

Here is what I got for jps command.

]0;taniya@taniya-VirtualBox: ~/hadoop/hadoop-1.2.1 taniya@taniya-VirtualBox:~/hadoop/hadoop-1.2.1$ jps

2497 SecondaryNameNode

2723 TaskTracker

2872 Jps

2584 JobTracker

2221 NameNode

2351 DataNode

The output/error I got from bin/hadoop jar  hadoop-examples-*.jar grep input output 'dfs[a-z.]+' is:

]0;taniya@taniya-VirtualBox: ~/hadoop/hadoop-1.2.1 taniya@taniya-VirtualBox:~/hadoop/hadoop-1.2.1$ bin/hadoop jar  

hadoop-examples-*.jar grep input output 'dfs[a-z.]+'

14/08/04 15:15:20 INFO util.NativeCodeLoader: Loaded the native-hadoop library

14/08/04 15:15:20 WARN snappy.LoadSnappy: Snappy native library not loaded

14/08/04 15:15:20 INFO mapred.JobClient: Cleaning up the staging area hdfs://localhost:9000/tmp/hadoop-taniya/mapred/staging/taniya/.staging/job_201408041513_0001

14/08/04 15:15:20 ERROR security.UserGroupInformation: PriviledgedActionException as:taniya cause:org.apache.hadoop.mapred.InvalidInputException: Input path does not exist: hdfs://localhost:9000/user/taniya/input

org.apache.hadoop.mapred.InvalidInputException: Input path does not exist: hdfs://localhost:9000/user/taniya/input

at org.apache.hadoop.mapred.FileInputFormat.listStatus(FileInputFormat.java:197)

at org.apache.hadoop.mapred.FileInputFormat.getSplits(FileInputFormat.java:208)

at org.apache.hadoop.mapred.JobClient.writeOldSplits(JobClient.java:1081)

at org.apache.hadoop.mapred.JobClient.writeSplits(JobClient.java:1073)

at org.apache.hadoop.mapred.JobClient.access$700(JobClient.java:179)

at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:983)

at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:936)

at java.security.AccessController.doPrivileged(Native Method)

at javax.security.auth.Subject.doAs(Subject.java:422)

at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1190)

at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:936)

at org.apache.hadoop.mapred.JobClient.submitJob(JobClient.java:910)

at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:1353)

at org.apache.hadoop.examples.Grep.run(Grep.java:69)

at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)

at org.apache.hadoop.examples.Grep.main(Grep.java:93)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:483)

at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:68)

at org.apache.hadoop.util.ProgramDriver.driver(ProgramDriver.java:139)

at org.apache.hadoop.examples.ExampleDriver.main(ExampleDriver.java:64)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:483)

at org.apache.hadoop.util.RunJar.main(RunJar.java:160)

]0;taniya@taniya-VirtualBox: ~/hadoop/hadoop-1.2.1 taniya@taniya-VirtualBox:~/hadoop/hadoop-1.2.1$ ls output/*

[0m [01;32moutput/part-00000 [0m   [01;32moutput/_SUCCESS [0m

The documents showing the two localhost UI is also attached. I see the SUCCESS message when I do 'ls output/*' after the hadoop command " bin/hadoop jar hadoop-examples-*.jar grep input output 'dfs[a-z.]+ ".

But I still see only 0 running nodes in the UI. 

Thanks,

Taniya

[Nitesh Jain]

Hi Taniya,

First of all Congratulations! You have got the installation perfectly right as I see all the demons running. The issue here is that the command is not able to find the 'input' path. You would be able to find that message in the output verbiage of the command, if you read it closely.

If you have made the changes to the configuration file core-site.xml,  mapred-site.xml and hdfs-site.xml and in the pseudo-distribution mode already (which I think you are), all you need to do is run the following command to create the input file on HDFS:

hadoop fs -mkdir input

and then again run the command to test hadoop framework.  However, if you were in standalone mode, then you would create a file on local file system by a simple command:

mkdir input 

Hope this works for you!

Best,

Nitesh

Hadoop-Skills.com

[Taniya Tom]

Hi Nitesh,

I created an input folder using the command 'hadoop fs -mkdir input' as you suggested.  Now this is what I get when I run the command to test hadoop framework. I see an ERROR message on an existing output directory. Should I delete this directory before executing a hadoop query everytime? Also, I am not able to locate the correct directory in my system.

There are two output folders in my system in these locations:

/home/taniya/hadoop/hadoop-1.2.1/docs/api/org/apache/hadoop/mapreduce/lib/output
/home/taniya/hadoop/hadoop-1.2.1/output                 
But the error message gives a path : Output directory hdfs://localhost:9000/user/taniya/output

I'm not sure what to do.

This is the output/error message that I get.

]0;taniya@taniya-VirtualBox: ~/hadoop/hadoop-1.2.1 taniya@taniya-VirtualBox:~/hadoop/hadoop-1.2.1$ bin/hadoop jar  

hadoop-examples-*.jar grep input output 'dfs[a-z.]+'

14/08/04 22:40:28 INFO util.NativeCodeLoader: Loaded the native-hadoop library

14/08/04 22:40:28 WARN snappy.LoadSnappy: Snappy native library not loaded

14/08/04 22:40:28 INFO mapred.FileInputFormat: Total input paths to process : 0

14/08/04 22:40:29 INFO mapred.JobClient: Running job: job_201408042239_0001

14/08/04 22:40:30 INFO mapred.JobClient:  map 0% reduce 0%

14/08/04 22:40:42 INFO mapred.JobClient:  map 0% reduce 100%

14/08/04 22:40:44 INFO mapred.JobClient: Job complete: job_201408042239_0001

14/08/04 22:40:44 INFO mapred.JobClient: Counters: 19

14/08/04 22:40:44 INFO mapred.JobClient:   Map-Reduce Framework

14/08/04 22:40:44 INFO mapred.JobClient:     Combine output records=0

14/08/04 22:40:44 INFO mapred.JobClient:     Spilled Records=0

14/08/04 22:40:44 INFO mapred.JobClient:     Reduce input records=0

14/08/04 22:40:44 INFO mapred.JobClient:     Reduce output records=0

14/08/04 22:40:44 INFO mapred.JobClient:     Virtual memory (bytes) snapshot=1848279040

14/08/04 22:40:44 INFO mapred.JobClient:     Reduce shuffle bytes=0

14/08/04 22:40:44 INFO mapred.JobClient:     Physical memory (bytes) snapshot=65650688

14/08/04 22:40:44 INFO mapred.JobClient:     Combine input records=0

14/08/04 22:40:44 INFO mapred.JobClient:     CPU time spent (ms)=250

14/08/04 22:40:44 INFO mapred.JobClient:     Reduce input groups=0

14/08/04 22:40:44 INFO mapred.JobClient:     Total committed heap usage (bytes)=33423360

14/08/04 22:40:44 INFO mapred.JobClient:   FileSystemCounters

14/08/04 22:40:44 INFO mapred.JobClient:     FILE_BYTES_WRITTEN=55776

14/08/04 22:40:44 INFO mapred.JobClient:     HDFS_BYTES_WRITTEN=86

14/08/04 22:40:44 INFO mapred.JobClient:   File Output Format Counters 

14/08/04 22:40:44 INFO mapred.JobClient:     Bytes Written=86

14/08/04 22:40:44 INFO mapred.JobClient:   Job Counters 

14/08/04 22:40:44 INFO mapred.JobClient:     Launched reduce tasks=1

14/08/04 22:40:44 INFO mapred.JobClient:     SLOTS_MILLIS_REDUCES=5751

14/08/04 22:40:44 INFO mapred.JobClient:     Total time spent by all reduces waiting after reserving slots (ms)=0

14/08/04 22:40:44 INFO mapred.JobClient:     SLOTS_MILLIS_MAPS=6970

14/08/04 22:40:44 INFO mapred.JobClient:     Total time spent by all maps waiting after reserving slots (ms)=0

14/08/04 22:40:44 INFO mapred.JobClient: Cleaning up the staging area hdfs://localhost:9000/tmp/hadoop-taniya/mapred/staging/taniya/.staging/job_201408042239_0002

14/08/04 22:40:44 ERROR security.UserGroupInformation: PriviledgedActionException as:taniya cause:org.apache.hadoop.mapred.FileAlreadyExistsException: Output directory hdfs://localhost:9000/user/taniya/output already exists

org.apache.hadoop.mapred.FileAlreadyExistsException: Output directory hdfs://localhost:9000/user/taniya/output already exists

at org.apache.hadoop.mapred.FileOutputFormat.checkOutputSpecs(FileOutputFormat.java:121)

at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:975)

at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:936)

at java.security.AccessController.doPrivileged(Native Method)

at javax.security.auth.Subject.doAs(Subject.java:422)

at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1190)

at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:936)

at org.apache.hadoop.mapred.JobClient.submitJob(JobClient.java:910)

at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:1353)

at org.apache.hadoop.examples.Grep.run(Grep.java:84)

at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)

at org.apache.hadoop.examples.Grep.main(Grep.java:93)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:483)

at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:68)

at org.apache.hadoop.util.ProgramDriver.driver(ProgramDriver.java:139)

at org.apache.hadoop.examples.ExampleDriver.main(ExampleDriver.java:64)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:483)

at org.apache.hadoop.util.RunJar.main(RunJar.java:160)

]0;taniya@taniya-VirtualBox: ~/hadoop/hadoop-1.2.1 taniya@taniya-VirtualBox:~/hadoop/hadoop-1.2.1$ 

]0;taniya@taniya-VirtualBox: ~/hadoop/hadoop-1.2.1 taniya@taniya-VirtualBox:~/hadoop/hadoop-1.2.1$ jps

4689 SecondaryNameNode

4771 JobTracker

4547 DataNode

5379 Jps

4406 NameNode

4924 TaskTracker

]0;taniya@taniya-VirtualBox: ~/hadoop/hadoop-1.2.1 taniya@taniya-VirtualBox:~/hadoop/hadoop-1.2.1$ bin/stop-all.sh 

Kindly help.

Thanks,

Taniya

On Sunday, August 3, 2014 7:46:33 PM UTC-7, Taniya Tom wrote:

[Nitesh Jain]

Hey Taniya,

You would need to change the output directory name as in HDFS there are no overwrites. This is a precautionary mechanism put in place just to same the results created after a long running job, so that you do not (even accidentally) overwrite the results from the previous runs.

What happened is that when you typed in the commands before this, the job didn't run but the output directory go created and so now you get the message that output directory already exists. So what you need to do is just change the name of the output directory. Make it from output to output1 (or something else you like) and  things would run just fine. Something like below:

bin/hadoop jar hadoop-examples-*.jar grep input output1 'dfs[a-z.]+'

Do let me know if you still face issues!

Cheers,

Nitesh

Hadoop-Skills.com

[Taniya Tom]

Hi Nitesh,

It says new output folder "out01" is not created.

Copying the typescript that I generated. 

taniya@taniya-VirtualBox:~$ ssh localhost

Welcome to Ubuntu 14.04.1 LTS (GNU/Linux 3.13.0-32-generic x86_64)

 * Documentation:  https://help.ubuntu.com/

*** System restart required ***

Last login: Tue Aug  5 11:16:59 2014 from localhost

taniya@taniya-VirtualBox:~$ cd hadoop/hadoop-1.2.1/

taniya@taniya-VirtualBox:~/hadoop/hadoop-1.2.1$ bin/start-all.sh

starting namenode, logging to /home/taniya/hadoop/hadoop-1.2.1/libexec/../logs/hadoop-taniya-namenode-taniya-VirtualBox.out

localhost: starting datanode, logging to /home/taniya/hadoop/hadoop-1.2.1/libexec/../logs/hadoop-taniya-datanode-taniya-VirtualBox.out

localhost: starting secondarynamenode, logging to /home/taniya/hadoop/hadoop-1.2.1/libexec/../logs/hadoop-taniya-secondarynamenode-taniya-VirtualBox.out

starting jobtracker, logging to /home/taniya/hadoop/hadoop-1.2.1/libexec/../logs/hadoop-taniya-jobtracker-taniya-VirtualBox.out

localhost: starting tasktracker, logging to /home/taniya/hadoop/hadoop-1.2.1/libexec/../logs/hadoop-taniya-tasktracker-taniya-VirtualBox.out

taniya@taniya-VirtualBox:~/hadoop/hadoop-1.2.1$ jps

10457 SecondaryNameNode

10314 DataNode

10539 JobTracker

10172 NameNode

10829 Jps

10687 TaskTracker

taniya@taniya-VirtualBox:~/hadoop/hadoop-1.2.1$ bin/hadoop jar hadoop-examples-*.jar grep input out01 'dfs[a-z.]+'

14/08/05 11:26:48 INFO util.NativeCodeLoader: Loaded the native-hadoop library

14/08/05 11:26:49 WARN snappy.LoadSnappy: Snappy native library not loaded

14/08/05 11:26:49 INFO mapred.FileInputFormat: Total input paths to process : 0

14/08/05 11:26:49 INFO mapred.JobClient: Running job: job_201408051125_0001

14/08/05 11:26:50 INFO mapred.JobClient:  map 0% reduce 0%

14/08/05 11:27:02 INFO mapred.JobClient:  map 0% reduce 100%

14/08/05 11:27:04 INFO mapred.JobClient: Job complete: job_201408051125_0001

14/08/05 11:27:04 INFO mapred.JobClient: Counters: 19

14/08/05 11:27:04 INFO mapred.JobClient:   Map-Reduce Framework

14/08/05 11:27:04 INFO mapred.JobClient:     Combine output records=0

14/08/05 11:27:04 INFO mapred.JobClient:     Spilled Records=0

14/08/05 11:27:04 INFO mapred.JobClient:     Reduce input records=0

14/08/05 11:27:04 INFO mapred.JobClient:     Reduce output records=0

14/08/05 11:27:04 INFO mapred.JobClient:     Virtual memory (bytes) snapshot=1848279040

14/08/05 11:27:04 INFO mapred.JobClient:     Reduce shuffle bytes=0

14/08/05 11:27:04 INFO mapred.JobClient:     Physical memory (bytes) snapshot=65585152

14/08/05 11:27:04 INFO mapred.JobClient:     Combine input records=0

14/08/05 11:27:04 INFO mapred.JobClient:     CPU time spent (ms)=260

14/08/05 11:27:04 INFO mapred.JobClient:     Reduce input groups=0

14/08/05 11:27:04 INFO mapred.JobClient:     Total committed heap usage (bytes)=33423360

14/08/05 11:27:04 INFO mapred.JobClient:   FileSystemCounters

14/08/05 11:27:04 INFO mapred.JobClient:     FILE_BYTES_WRITTEN=55778

14/08/05 11:27:04 INFO mapred.JobClient:     HDFS_BYTES_WRITTEN=86

14/08/05 11:27:04 INFO mapred.JobClient:   File Output Format Counters 

14/08/05 11:27:04 INFO mapred.JobClient:     Bytes Written=86

14/08/05 11:27:04 INFO mapred.JobClient:   Job Counters 

14/08/05 11:27:04 INFO mapred.JobClient:     Launched reduce tasks=1

14/08/05 11:27:04 INFO mapred.JobClient:     SLOTS_MILLIS_REDUCES=5638

14/08/05 11:27:04 INFO mapred.JobClient:     Total time spent by all reduces waiting after reserving slots (ms)=0

14/08/05 11:27:04 INFO mapred.JobClient:     SLOTS_MILLIS_MAPS=6778

14/08/05 11:27:04 INFO mapred.JobClient:     Total time spent by all maps waiting after reserving slots (ms)=0

14/08/05 11:27:05 INFO mapred.FileInputFormat: Total input paths to process : 1

14/08/05 11:27:05 INFO mapred.JobClient: Running job: job_201408051125_0002

14/08/05 11:27:06 INFO mapred.JobClient:  map 0% reduce 0%

14/08/05 11:27:14 INFO mapred.JobClient:  map 100% reduce 0%

14/08/05 11:27:24 INFO mapred.JobClient:  map 100% reduce 33%

14/08/05 11:27:25 INFO mapred.JobClient:  map 100% reduce 100%

14/08/05 11:27:27 INFO mapred.JobClient: Job complete: job_201408051125_0002

14/08/05 11:27:27 INFO mapred.JobClient: Counters: 29

14/08/05 11:27:27 INFO mapred.JobClient:   Map-Reduce Framework

14/08/05 11:27:27 INFO mapred.JobClient:     Spilled Records=0

14/08/05 11:27:27 INFO mapred.JobClient:     Map output materialized bytes=6

14/08/05 11:27:27 INFO mapred.JobClient:     Reduce input records=0

14/08/05 11:27:27 INFO mapred.JobClient:     Virtual memory (bytes) snapshot=3696443392

14/08/05 11:27:27 INFO mapred.JobClient:     Map input records=0

14/08/05 11:27:27 INFO mapred.JobClient:     SPLIT_RAW_BYTES=117

14/08/05 11:27:27 INFO mapred.JobClient:     Map output bytes=0

14/08/05 11:27:27 INFO mapred.JobClient:     Reduce shuffle bytes=6

14/08/05 11:27:27 INFO mapred.JobClient:     Physical memory (bytes) snapshot=245657600

14/08/05 11:27:27 INFO mapred.JobClient:     Map input bytes=0

14/08/05 11:27:27 INFO mapred.JobClient:     Reduce input groups=0

14/08/05 11:27:27 INFO mapred.JobClient:     Combine output records=0

14/08/05 11:27:27 INFO mapred.JobClient:     Reduce output records=0

14/08/05 11:27:27 INFO mapred.JobClient:     Map output records=0

14/08/05 11:27:27 INFO mapred.JobClient:     Combine input records=0

14/08/05 11:27:27 INFO mapred.JobClient:     CPU time spent (ms)=1350

14/08/05 11:27:27 INFO mapred.JobClient:     Total committed heap usage (bytes)=179900416

14/08/05 11:27:27 INFO mapred.JobClient:   File Input Format Counters 

14/08/05 11:27:27 INFO mapred.JobClient:     Bytes Read=86

14/08/05 11:27:27 INFO mapred.JobClient:   FileSystemCounters

14/08/05 11:27:27 INFO mapred.JobClient:     HDFS_BYTES_READ=203

14/08/05 11:27:27 INFO mapred.JobClient:     FILE_BYTES_WRITTEN=110049

14/08/05 11:27:27 INFO mapred.JobClient:     FILE_BYTES_READ=6

14/08/05 11:27:27 INFO mapred.JobClient:   File Output Format Counters 

14/08/05 11:27:27 INFO mapred.JobClient:     Bytes Written=0

14/08/05 11:27:27 INFO mapred.JobClient:   Job Counters 

14/08/05 11:27:27 INFO mapred.JobClient:     Launched map tasks=1

14/08/05 11:27:27 INFO mapred.JobClient:     Launched reduce tasks=1

14/08/05 11:27:27 INFO mapred.JobClient:     SLOTS_MILLIS_REDUCES=10509

14/08/05 11:27:27 INFO mapred.JobClient:     Total time spent by all reduces waiting after reserving slots (ms)=0

14/08/05 11:27:27 INFO mapred.JobClient:     SLOTS_MILLIS_MAPS=9941

14/08/05 11:27:27 INFO mapred.JobClient:     Total time spent by all maps waiting after reserving slots (ms)=0

14/08/05 11:27:27 INFO mapred.JobClient:     Data-local map tasks=1

taniya@taniya-VirtualBox:~/hadoop/hadoop-1.2.1$ ls out01/*

ls: cannot access out01/*: No such file or directory

taniya@taniya-VirtualBox:~/hadoop/hadoop-1.2.1$ bin/stop-all.shstopping jobtracker

localhost: stopping tasktracker

stopping namenode

localhost: stopping datanode

localhost: stopping secondarynamenode

taniya@taniya-VirtualBox:~/hadoop/hadoop-1.2.1$ exit

logout

Connection to localhost closed.

Thank you for reaching out to help me.

Taniya

[Nitesh Jain]

Hey Taniya,

First of all accept my Congratulation! That is a successful run of program!

The out01 got created on HDFS and not on the local file system. So when you would do a ls on HDFS by the command:

hadoop fs -ls

You should see the out01 folder. Inside that you would see other files like the log file and the output file. This would be covered later in the course how to see the output files and understand the verbiage of the successfully completed command.

Hadoop installation is a little tricky. Appreciate your efforts to be patient and install it successfully!

Best,

Nitesh

Hadoop-Skills.com

[Taniya Tom]

Thank you Nitesh.

Taniya

On Tuesday, August 5, 2014 10:26:47 PM UTC-7, Nitesh Jain wrote:

Hey Taniya,

First of all accept my Congratulation! That is a successful run of program!

The out01 got created on HDFS and not on the local file system. So when you would do a ls on HDFS by the command:

hadoop fs -ls

You should see the out01 folder. Inside that you would see other files like the log file and the output file. This would be covered later in the course how to see the output files and understand the verbiage of the successfully completed command.

Hadoop installation is a little tricky. Appreciate your efforts to be patient and install it successfully!

Best,

Nitesh

Hadoop-Skills.com