Common Kerberos commands: 1.Change password of a principal(user) $ kadmin.local kadmin.local: cpw <principalname> Enter password for princal "principalname@REALM.COM": 2.initialize a kerberos ticket $ kinit <principalname> To get detailed verbose info use below options: $ KRB5_TRACE=/dev/stdout kinit -V 3. Destroy the current ticket: $ kdestroy 4. Check the status of Kerberos KDC $ systemctl status kadmin $ systemctl … Continue reading Kerberos commands
Following steps are needed to run a Java program in Hadoop with Kerberos security enabled: 1. Create a text file named FileCount.java and store it in your home directory such as /home/userid 2. Copy paste the below code into the file FileCount.java . Change the hadoop hostname from quickstart.cloudera:8020 to the correct host. import java.io.*; import … Continue reading Run a Java program in Hadoop with Kerberos enabled.
SPNEGO, and WebHDFS on Hadoop using Chrome browser: Reference: http://www.ghostar.org/2015/06/google-chrome-spnego-and-webhdfs-on-hadoop/ We want to see if the Chrome browser can be used to authenticate users with Kerberos and display Hadoop webhdfs REST api data. In the Cloudera Security .pdf manual follow these steps: Step 9: (Optional) Enable Authentication for HTTP Web Consoles for Hadoop Roles … Continue reading Kerberos, SPNEGO and WebHDFS on Hadoop using Chrome browser:
If you have a Centos server and want to install Chrome browser which will display GUI on Windows laptop using X server then follow these steps: First download and install Mobax terminal software on your laptop from https://mobaxterm.mobatek.net/ . This will provide the X server needed to display the browser on windows. Enable Google YUM … Continue reading Install Google Chrome on Centos 7
Reference: http://blog.cloudera.com/blog/2015/03/how-to-quickly-configure-kerberos-for-your-apache-hadoop-cluster/ Cloudera Security manual .pdf – CDH 5.15 on Cloudera Documentation website http://www.ghostar.org/2015/06/google-chrome-spnego-and-webhdfs-on-hadoop/ https://www.youtube.com/watch?v=4TwU0LwDJAg Environment: Cloudera CDH 5.15 on Centos 7 MIT KDC Kerberos Setting up Kerberos in Cloudera CDH is somewhat tricky. The above blog is a good step by step way to setup. Also refer to the official Cloudera Security … Continue reading Kerberos setup in Cloudera Hadoop
Virtualbox network setup for internet access: Generally the following table gives the connectivity for different Virtualbox Network adapters. Sometimes it is possible the Bridged network wont get an ipv4 address and cannot connect to internet. Then we have to setup both a NAT and a Host-only adapter network. The requirement is: Host is Windows 10, … Continue reading Virtualbox VM setups.
Reference: http://linuxresolved.com/upgrade-mysql-5-6-mysql-5-7-centos/ 1. # service mysql stop 2. Important backup your databases before upgrade. Create a backup of the original MySQL data. mv /var/lib/mysql /var/lib/mysql.original 2. Download the MySQL 5.7 RPM wget http://repo.mysql.com/mysql57-community-release-el7.rpm -P /tmp/ 3. Remove the MySQL-Community RPM that contains MySQL 5.6 yum remove mysql-community-release 4. Install the MySQL 5.7 RPM rpm -ivh /tmp/mysql57-community-release-el7.rpm … Continue reading Upgrade MySQL 5.6 to 5.7 on Centos 7
In Ubuntu, the server is run as a service called postgresql (configured in /etc/init.d/postgresql). The postgresql service is started automatically upon startup. Like all other services, you could: $ sudo service postgresql stop // Stop the service $ sudo service postgresql start // Start the service $ sudo service postgresql restart // Stop and restart the service $ sudo service postgresql reload … Continue reading PostgreSQL notes
In Ubuntu 16.04 by default root login by SSH is blocked for security reason. To enable root to login by SSH we have to update the ssh configuration. NOTE: This may make your server insecure for hackers so just enable root login temporarily if needed. /etc/ssh# ssh root Permission denied (publickey). Next edit the file: /etc/ssh# vi sshd_config Change the following … Continue reading Enable SSH login to Ubuntu by root user
Below blog has good instructions: https://www.digitalocean.com/community/tutorials/how-to-install-java-with-apt-get-on-ubuntu-16-04