Delete files older than 30days on HDFS

This post helps in cleanup of HDFS files older than a certain date(30days) using a shell script.

 #!/bin/sh  
 #finding HDFS load time of particular folder  
 today=`date +'%s'`  
 hdfs dfs -ls /file/Path/ | grep "^d" | while read line ; do  
 dir_date=$(echo ${line} | awk '{print $6}')  
 difference=$(( ( ${today} - $(date -d ${dir_date} +%s) ) / ( 24*60*60 ) ))  
 filePath=$(echo ${line} | awk '{print $8}')  
 if [ ${difference} -gt 30 ]; then  
   hdfs dfs -rm -r $filePath  
 fi  
 done  

If you are facing any problems in deleting files, then please comment here.

How to Change the priority of Hadoop Jobs (Hive,MapReduce,pig)?

Hadoop provides a command line utility for changing the priority of running job. There are total 5 different priority level are there. These priority levels are listed below:

VERY_HIGH
HIGH
NORMAL
LOW
VERY_LOW

We can change the priority of the running hadoop job syntax is shown below:

 hadoop job -set-priority <job-id> <priority>  

Example:

 hadoop job -set-priority job_20170111540_64444 VERY_HIGH  

From the names of the priority levels, it is quite obvious that highest priority is given to the jobs whose priority level is VERY_HIGH and least priority is given to the jobs whose priority level is VERY_LOW.

Priority in Map Reduce Program:

In order to set priority for a job on Hadoop 1 cluster, you can use the following example:

 -> SET mapred.job.priority=<priority_value>;  

In order to set priority for a job on Hadoop 2 cluster, you can use the following example:

 -> SET mapreduce.job.priority=<priority_value>;  

Priority in Pig Program:

The below property is used to set the job priority is Pig Programming.

 grunt> SET job.priority 'high'  

The following <priority_value> values are supported:
very_low, low, normal, high, very_high

Priority for Hive Query:

In order to set priority for a HIVE query on Hadoop 1 cluster, you can use the following example:

 hive> SET mapred.job.priority=VERY_HIGH;  

In order to set priority for a HIVE query on Hadoop 2 cluster, you can use the following example:

 hive> SET mapreduce.job.priority=VERY_HIGH;  

If you are facing any problems in changing the priority of the hadoop jobs, then please comment here.