Apt-Get is not resolving us.archive.ubuntu.com / wget: unable to resolve host address

I had faced this issue a lot of times when i try to download / install any software, i was able to access the same URL in browser but not in terminal:

I fixed my problem by fixing a DNS address manually into file /etc/resolv.conf to DNS address of my operator. 

Previously it was set to 192.168.0.254 by Ubuntu.


$cat /etc/resov.conf

nameserver 8.8.8.8

nameserver 192.168.0.254

Openstack installation in few steps (Single Node Setup)

1. Download and Install Oracle Virtual Box


2. Download Ubuntu Operating System Image file, and create a virtual machine.

    If you face any issues then check and enable the virtualization options in your BIOS settings.


3.  While creating vm, you may end up with 2 options try Ubuntu / Install Ubuntu, click on Install Ubuntu.

4. Once the installation is over then follow the below steps to setup openstack in your vm.

                     a. sudo apt-get update

                     b. sudo apt-get upgrade

                     c. sudo apt-get install git
                     d. sudo git clone –b stable/icehouse https://github.com/openstack-dev/devstack.git

                     e. cd devstack

                     f. sudo wget –O localrc http://goo.gl/OeOGqL

                     g. ./stack.sh

now you can access openstack url http://localhost


the default credentials are:

Username  : admin / demo

password  :  openstack

NOTE : you may face some permission issues, please modify the permissions accordingly.

Setting Environment Variables with Spaces in the Path

1. We can use one temp variable to store the path with  spaces, after we can use this variable for setting the environment variables.

For ex:

to set JAVA_HOME, I can use below commands:

set temp=c:\program files\java\jre7

set JAVA_HOME="%temp%"

2. we can simply go with the below approach:


  set "JAVA_HOME=c:\program files\java\jre7"

Powershell Script to Convert xlsx to csv

Use the below code to convert the xlsx file into csv:


$xlsx_file="C:\Users\v-gibag\Desktop\locations.xlsx"
$csv_file="C:\Users\v-gibag\Desktop\user1.csv"
$Excel = new-object -comobject excel.application
$book = $Excel.Workbooks.Open($xlsx_file)
$book.SaveAs($csv_file,6)
$book.Close($false)
$Excel.quit()

How to submit hive query to HDinsight cluster from Powershell

1. Open azure power shell , please type the following command

    Get-AzurePublishSettingsFile

   It will open Azure login page, enter the credentials

 

       

Once after successful login, the Public settings file will be downloaded automatically.

2. After use the below Import command to import the settings file   

                                     

Import-AzurePublishSettingsFile <path to file>      

3.please use the below script to connect to hive and run hive.

$subscriptionName = "Azure in Open"

PS C:\> $clusterName = "IngramCluster"

PS C:\> Select-AzureSubscription $subscriptionName

PS C:\> Select-AzureSubscription -SubscriptionName $subscriptionName

PS C:\> Use-AzureHDInsightCluster $clusterName

Successfully connected to cluster IngramCluster

PS C:\> Invoke-Hive -Query "select * from hivesampletable limit 5;"

Submitting Hive query..

Started Hive query with jobDetails Id : job_1421995004773_0004

Hive query completed Successfully

8       18:54:20        en-US   Android Samsung SCH-i500        California      United States   13.9204007      0

0

23      19:19:44        en-US   Android HTC     Incredible      Pennsylvania    United States   NULL    0       0

23      19:19:46        en-US   Android HTC     Incredible      Pennsylvania    United States   1.4757422       0

1

23      19:19:47        en-US   Android HTC     Incredible      Pennsylvania    United States   0.245968        0

2

28      01:37:50        en-US   Android Motorola        Droid X Colorado        United States   20.3095339      1

                        

Calling SQL Stored procedure from R

The Following lines in R calls a stored  procedure in SQL SEREVR 

library(RODBC)
conn <- odbcDriverConnect('driver={SQL Server};server=HostName;database=DatabaseName;uid=useName;pwd=Password')
query <- paste("exec  dbo.R_getData ");
res<-sqlQuery(conn, query);

Enable oozie workflow for new mapReduce API

If you are using new MapReduce API, and wants to execute implement DAG with oozie workflow, then you
may face the below exception :

java.lang.RuntimeException: Error in configuring object
 at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:93)
 at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:64)
 at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.jav

Caused by: java.lang.reflect.InvocationTargetException

 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:597)
 at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:88)
 ... 9 more

Caused by: java.lang.RuntimeException: java.lang.RuntimeException: class TestMapper not org.apache.hadoop.mapred.Mapper
 at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:899)
 
Caused by: java.lang.RuntimeException: class TestMapper not org.apache.hadoop.mapred.Mapper
 at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:893)
 ... 16 more

To solve the above issue, we need to have two properties in workflow.xml,

<property>

    <name>mapred.reducer.new-api</name>

    <value>true</value>

  </property>

  <property>

    <name>mapred.mapper.new-api</name>

    <value>true</value>

</property>

now replace the workflow.xml in HDFS with updated one, the issue will be resolved.....