R Setup in Ubuntu

R is a statistical package to analyze data. I came across this framework while exploring Hortonworks Hadoop Data Platform and want to list down the steps to setup R – Steps on how to use R is not covered here:

1. Open Terminal and Run following commands:
sudo apt-get update
sudo apt-get install r-base
2. Above would install R 2.14.1. To upgrade to latest version, append following to “/etc/apt/sources.list” and run “sudo apt-get update” once again:
deb http://cran.rstudio.com/bin/linux/ubuntu precise/

3. In my Ubuntu, executing above, generated following error:

W: GPG error: http://cran.rstudio.com precise/ Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 51716619E084DAB9

4. To resolve above error, execute following commands:
gpg –keyserver pgpkeys.mit.edu –recv-key 51716619E084DAB9
gpg -a –export 51716619E084DAB9 | sudo apt-key add -
Reference: http://ubuntuforums.org/archive/index.php/t-2154184.html

5. Run following command to upgrade all packages:
sudo apt-get upgrade

Note: To find #packages ubuntu has, use following command – more #packages, more time is taken to upgrade (be ready to do plan for alternative task during this time – upgrade took me 2-3 hours):
dpkg –get-selections | grep -v deinstall > packages.txt

Reference: ubuntuforums.org/archive/index.php/t-2154184.html

6. Run “R” in terminal and we would see R’s console.

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Linux – 32 bit or 64 bit?

Installing a New Software in Linux VM? Perform the following check to determine if Linux VM is running on 32 bit or 64 bit and then download the correct version:

1. Open Terminal

2. Run uname -a

3. Result for 32-bit linux would be:

Linux discworld 2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:50 UTC 2011 i686 i686 i386 GNU/Linux

4. Result for 64-bit linux would be:

Linux discworld 2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:50 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

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Increasing traffic, content engagement and Social tools

How to Increasing traffic, content engagement and revenue by showing Social tools? Smart Layers by AddThis helps in this area – refer WordPress › Smart Layers by AddThis « WordPress Plugins.

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Comparison of RabbitMQ, ActiveMQ, and ZeroMQ Message Brokers

A Concise Comparison of RabbitMQ, ActiveMQ, and ZeroMQ Message Brokers | Javalobby

RabbitMQ is one of the leading implementation of the AMQP protocol (along with Apache Qpid). Therefore, it implements a broker architecture, meaning that messages are queued on a central node before being sent to clients. This approach makes RabbitMQ very easy to use and deploy, because advanced scenarios like routing, load balancing or persistent message queuing are supported in just a few lines of code. However, it also makes it less scalable and “slower” because the central node adds latency and message envelopes are quite big.


ZeroMQ is a very lightweight messaging system specially designed for high throughput/low latency scenarios like the one you can find in the financial world. Zmq supports many advanced messaging scenarios but contrary to RabbitMQ, you’ll have to implement most of them yourself by combining various pieces of the framework (e.g : sockets and devices). Zmq is very flexible but you’ll have to study the 80 pages or so of the guide (which I recommend reading for anybody writing distributed system, even if you don’t use Zmq) before being able to do anything more complicated that sending messages between 2 peers.


ActiveMQ is in the middle ground. Like Zmq, it can be deployed with both broker and P2P topologies. Like RabbitMQ, it’s easier to implement advanced scenarios but usually at the cost of raw performance. It’s the Swiss army knife of messaging.


Finally, all 3 products:

•   Have client APIs for the most common languages (C++, Java, .Net, Python, Php, Ruby, …)

•   Have strong documentation

•   Are actively supported

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Virtualization Technologies


There are many virtualization technologies are available in the market today, some of them are OpenVZ, Xen, KVM and VMware, you can understand about all these technologies.


It is an operating system level virtualization technology based on linux kernel and it allows a physical server to run multiple operating systems. It creates multiple secure and isolated linux containers on a single physical server, each container performs as a standalone server and a container can independently reboot. It is a free service and runs only linux based operating systems such as Fedora, Debian, Centos and Gentoo.


Xen is an open source software, it allows multiple operating systems to run on a single physical computer by using a layer called a hypervisor. The Hypervisor is a program that allows multiple operating systems to share a single hardware. Xen supports Linux kernels through an approach called paravirtualization. It is used for both linux and windows.


KVM stands for kernel based virtual machine, built for linux OS that enables linux to work as a hypervisor to run multiple virtual machines. It is designed to operate on x86-based processor architecture. It is free and supports Linux, windows, salaries and BSD guests, It is the basis for IBM’s and Red hat’s Linux virtualization technologies, it is the most used technology in the OpenStack cloud. OpenStack is a global collaboration of developers and technologists to produce an open cloud computing platform.


It is Cloud computing and virtualization software for x86 compatible computers, it is based on ESX/ESXi bare metal hypervisor. VMware ESX and ESXi can be deployed as part of the VMware infrastructure to empower centralized management for enterprise desktops and data center applications. VMware server works with Linux, Windows, Solaris and Netware. It is the most mature virtualization and most expensive also.

Eventually Virtualization technology employed by virtual private servers, whereby a physical server divided into virtual divisions, and these technologies provides you higher reliability and greater performance.

- See more at: http://www.alphavbox.com/blog/a-guide-to-virtualization-technologies/#sthash.qOaRXKSf.dpuf

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Beyond Chef and Puppet: Ten essential DevOps tools

1. Git and GitHub: Git is a repository for storing versions of code, otherwise known as a revision-control system; GitHub is a publicly hosted repository of code that can be downloaded and shared. Both are key for running DevOps environments, according to Matt Lanier, keeper of keys and grounds for Tout, a short-form video delivery firm based in San Francisco.

“We use Git for everything you can possibly use it for,” Lanier said. “Most people use it for revision control, but we use it for provisioning.”

In the company’s Amazon Web Services (AWS) environment, there’s one Git repository; on the other side of the wire in Tout’s data center is another. When provisioning Amazon instances, Tout’s cookbooks point to bits in the Git repository as templates.

2. Jenkins: This open source continuous integration server is essential for testing new code before deployment, according to a number of attendees here.

3. Berkshelf: This open source tool, maintained by Riot Games, offers a way of managing how cookbooks are fetched and deployed to a Chef server in order to make sure the right versions of cookbooks are being run. “If you’re not using Berkshelf in your cookbook development, you’re just doing it wrong,” said Trotter Cashion, founder of a consulting company called Mashion, in a session presentation this week.

4. Perforce: This proprietary revision-control system developed by Perforce Software Inc. is a must-have at Edmunds.com, a publisher of automotive information websites based in Santa Monica, Calif., according to Linux admin Joshua Miller. “Our essential tools are CloudStack, Chef and Perforce,” he said.

5. Nagios: Monitoring how changes to code affect the environment is crucial in deploying applications. The Nagios open source monitoring utility is tried and true — and free.

6. Sensu: Some attendees at ChefConf have moved from Nagios to Sensu, another open source monitoring utility. “I prefer Sensu because Nagios typically requires you to open a lot of firewall holes,” said Miah Johnson, DevOps engineer for Hotel Tonight, a last-minute lodging reservation service based in San Francisco.

7. LogStash: Johnson added that open source-based log-parsing utility LogStash is also key in her environment, providing another way to offer developers feedback on how code is performing by parsing and indexing logs. “It helps you figure out what the important parts of the logs are, and generates metrics based on your logs,” she said.

8. Test Kitchen: This tool allows users to test a Chef cookbook without actually running anything on the Chef Server, a sort of dry run in the cookbook development process.

9. Vagrant: Another lightweight test tool that allows for cookbooks and other software to be run on a virtual machine on a desktop.

10. Foodcritic: This is a really cool open source tool to look at a cookbook and test Chef correctness, said Phil Dibowitz, systems engineer for Facebook. “For us, it catches a lot of the really common errors that people could potentially make, especially if they’re new to Chef.”

Beyond Chef and Puppet: Ten essential DevOps tools.

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How To? Linux Delete Symbolic Link ( Softlink )

Linux Delete Symbolic Link ( Softlink ).

Create symbolic link
sudo ln -s <link name> <target file/folder>

Delete Symbolic Link File – Use the following syntax:
rm linkname (or) unlink linkname

Delete Symbolic Link Directory – Use the following syntax:
rm linkDirName (or) unlink linkDirName


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