Understanding Cloud Computing

Now a days a cloud computing can be hear every where. But actually what is the cloud computing. Why such name ?

If we open any book and find the diagram depicting the Internet its always a cloud so the term cloud is used as a metaphor for the Internet. It is abstraction of the complex infrastructure of the Internet. But we don't care much about what that cloud contains or what it have. We know its used for sending and receiving data. So cloud is internet.

Now a days we use web application for almost all the tasks. Take an example of gmail,yahoo or any other web mail . What we do their ? We open the page give our login information. Data is retrieved from the server. So the client part is doing almost nothing in this case. A simple but powerful example of Cloud Computing. In this case we can say, We open web mail enter credential details and the cloud takes care of the rest. So a great workload shift from client.

Cloud is nothing but various computers, servers , data storage etc... In general term anything that involves delivering hosted service over the internet is cloud computing. These services can be divided in three categories:
1. IaaS - Infrastructure-as-a-service
2. PaaS - Platform-as-a-service
3. SaaS - Software-as-as-service


Infrastructure-as-a-Service like Amazon Web Services provides virtual server instances with unique IP addresses and blocks of storage on demand.

Platform-as-a-service in the cloud is defined as a set of software and product development tools hosted on the provider's infrastructure. Developers create applications on the provider's platform over the Internet. PaaS providers may use APIs, website portals or gateway software installed on the customer's computer. GoogleApps are examples of PaaS. Developers need to know that currently, there are not standards for interoperability or data portability in the cloud. Some providers will not allow software created by their customers to be moved off the provider's platform.

In the software-as-a-service cloud model, the vendor supplies the hardware infrastructure, the software product and interacts with the user through a front-end portal. SaaS is a very broad market. Services can be anything from Web-based email to inventory control and database processing. Because the service provider hosts both the application and the data, the end user is free to use the service from anywhere.

Again a cloud can be public, private or hybrid. Eg: Public Cloud - Amazon Web Service. So public clouds sells a service to everyone on the internet. Private coluds is a proprietary network that supplies hosted services. Hybrid cloud consist of many internal / external providers.

So main goal of cloud computing is to provide easy, scalable access to computing resources.

Key Features as described on wiki are :
- Agility
- Device and location independence
- Multi - tenancy
- Reliability
- Scalability
- Security
- Sustainability

Why cloud computing ?

- Cost cutting on client hardware side
- Clients can access data anytime anywhere.(In n/w)
- No need to buy for each user/employee.
- Storng data on someone else PC no client storage
- Less hardware issues at client side


Useful links
1. http://en.wikipedia.org/wiki/Cloud_computing

Configuring bzr for windows

Bazaar is distributed version control system. Launchpad is a place for hosting bazaar code. Bazaar and launchpad need ssh key pair to work on with. The use of ssh key pair that is private/public key pair safeguards against any kind of brute force attack.

Bazaar runs on Windows, GNU/Linux, UNIX and Mac OS, and requires only Python 2.4.


Generating key pair on windows :

1. Download bazaar from http://bazaar-vcs.org/Download

2. Download PuttyGen and Pageant

3. Run PuttyGen it will show :

4. Click on generate and move mouse to generate randomness






















5. Enter the keyphrase and save both key


















So the pair of keys generated. This can be used on launchpad to register your key.


Generating key pair in linux

1. Open terminal

2. Run ssh-keygen -t rsa

3. When asked enter the file name for keys to be saved.

4. Enter password to protect you keys

5. File normally get saved in ~/.ssh/id_rsa.pub

This can be used as public key.

Registering key on Launchpad

Ii your ssh key page paste the public key and import and hence your pc is ready for launchpad work :)

In windows we need to run the pageant to load the key.

Search and delete lines in vim

vim is great editor but one must remember some commands. Sometimes we want to delete line as per the search criteria. vim is capable of that also. To delete the lines as per search use

:g/editor choice/d

This will delete all the lines that have the word "editor choice". Offcourse we can use regular expression too.

:g/regex/d

Pretty simple g tells to do thing globally. / for pattern enclosing . d for deleting.

Enjoy vim :)

Setting port forwarding for Torrent Client

Port forwarding is required for getting good download speed from torrent. To make sure port forwarding is ok with your torrent client find Test if port forwarded properly option in u r torrent client. Normally its under the speed test / speed guide.

If it is configured it says ok else say some error. In Azures client is shows in the status bar whether NAT is ok or fire walled.

Lets see how we can configure port forwarding. If u are using BSNL or any other connection open you configuration page.

1. Type 192.168.1.1 in address bar of your browser which take you to your configuration page which look like

2. Go in to Advance option -> NAT

3. Click on Add. Give custom name say torrent

4. Give your server ip address (192.168.1.1)

5. In the port start and end column enter the port you find in speed guide of your torrent client. Save it

6. Reboot your modem and torrent client.

7. Speed test will be success on port and NAT will show ok in status bar.

Enjoy downloading torrent with good speed

Giving power to vim - 2

vim one of powerful editor in linux. Here are few tips to make it more powerful

1. Setting auto completion
autocmd FileType python set omnifunc=pythoncomplete#Complete
autocmd FileType javascript set omnifunc=javascriptcomplete#CompleteJS
autocmd FileType html set omnifunc=htmlcomplete#CompleteTags
autocmd FileType css set omnifunc=csscomplete#CompleteCSS
autocmd FileType xml set omnifunc=xmlcomplete#CompleteTags
autocmd FileType php set omnifunc=phpcomplete#CompletePHP
autocmd FileType c set omnifunc=ccomplete#Complete

Giving power to vim - 1

To use vim efficiently and effectively we need to do some settings.

Open vimrc file. Its normally under HOME directory and hidden. On ubuntu
gedit ~/.vimrc will open it in gedit .

Add Following in to it:

1. Keeping History : Vim only remembers the last 20 commands and search patterns entered.
set history 1000

2. To show line numbers : set nu

3. To show syntax highlighting : set syntax on

4. To show menu with possible tab completions : set wildmenu

5. To set background : set background=dark

6. To set terminal title to filename : set title

Installing / adding fonts in ubuntu

Ubuntu comes with variety of fonts. But if we still have an urge for installing some extra fonts from windows or some other fonts how we do it. To add the fonts in ubuntu is very easy and can be done in few steps.

Fonts normally get installed in /usr/share/fonts/truetype. Simple way of adding font is to make one folder in said path and copy the font files in it. To open this folder with root access type sudo nautalius. This will open the file explorer in root mode.

The other way is to add the fonts in /home//.fonts

To refresh or update font cache run sudo fc-cache -f -v.