Using Cloud Computing

I am sure we all are using so call cloud computing solutions in our day to day activities / operations either knowingly or unknowingly. And it is equally true that the improvisation of Operating System or the platform running over our enormous hardware has helped us to improvise utilisation of available resources. Take an example most of my emails and personal document management is taken care by google apps and if I have to deploy my online application and want to purely concentrate on my business rather than worry about Infrastructure, hardware scoping, infrastructure management, high availability, up-scaling, etc. and most important CAPEX, it would make more sense in using offerings made by Amazon and others, as this will help me to concentrate more on my business operations & activities and let the service provider manage the Infrastructure. And yes, SaaS (Software as a Service), PaaS (Platform as a Service) & IaaS (Infrastructure as a Service) will be the focus and not just selling boxes or softwares.

Cloud Computing

Everybody is busy talking ga ga about cloud computing ... I sometime wonder why .... cloud computing is just a repackaging & selling of mainframe technology. The same old technology with same old features like batch processing, multi functional, virtualisation, storage etc.

Nginx (engine x) – Installation Guide on CentOS

1] Download source code of Nginx from the official site (http://nginx.net/)

To get stable version as per this tutorial dated is

$ wget http://sysoev.ru/nginx/nginx-0.7.61.tar.gz

or

To get development version as per this tutorial dated is

$ wget http://sysoev.ru/nginx/nginx-0.8.7.tar.gz

(Note : For production server use stable version only)


2] We store downloaded file under a directory, for example we will use 'download' directory

$ mkdir ~/download

$ cp nginx-0.6.36.tar.gz ~/download

$ cd download


3] Install required Nginx dependencies

pcre pcre-devel zlib zlib-devel openssl openssl-devel

so using default package manager of CentOS

$ sudo yum install pcre pcre-devel zlib zlib-devel openssl openssl-devel


4] Create required Nginx user and group ids

$ sudo /usr/sbin/groupadd nginx

$ sudo /usr/sbin/useradd –g nginx –s /bin/false nginx


5] Proceed with source installation of Nginx

$ cd ~/download

unzip the source file

$ tar -zxvf nginx-0.7.61.tar.gz

$ cd nginx-0.7.61


6] Configure Nginx source

$ ./configure \

--prefix=/usr/local/nginx \

--sbin-path=/usr/local/sbin \

--conf-path=/usr/local/nginx/nginx.conf \

--http-log-path=/var/log/nginx/access.log \

--error-log-path=/var/log/nginx/error.log \

--pid-path=/var/run/nginx/nginx.pid \

--lock-path=/var/lock/nginx.lock \

--user=nginx \

--group=nginx \

--http-client-body-temp-path=/var/tmp/nginx/client/ \

--http-proxy-temp-path=/var/tmp/nginx/proxy/ \

--http-fastcgi-temp-path=/var/tmp/nginx/fcgi/ \

--with-http_ssl_module \

--with-http_realip_module \

--with-http_perl_module \

--with-http_flv_module \

--with-http_gzip_static_module \

--with-http_stub_status_module \

--with-md5-asm \

--with-md5=auto/lib/md5 \

--with-sha1-asm \

--with-sha1=auto/lib/sha1


7] Make and Install

$ make

$ sudo make install


8] Change ownerships before we proceed

$ sudo chown nginx:nginx –R /usr/local/nginx


9] Create following directories with required ownership to proceed

$ sudo mkdir -p /var/tmp/nginx /{client,proxy,fcgi}

$ sudo chown nginx:nginx -R /var/tmp/nginx


10] Start Nginx

$ sudo /usr/local/sbin/nginx

If we get no error while starting Nginx then lets check running process status by executing following command and getting similar output as below

$ ps aux | grep nginx

root 10009 0.0 0.0 5524 592 ? Ss 07:21 0:00 nginx: master process /usr/local/sbin/nginx

nginx 10010 0.0 0.0 5716 928 ? S 07:21 0:00 nginx: worker process


11] And we are ready to use Nginx

Open your browser and type ip address of your server or just type localhost.

http://localhost

http://127.0.0.1


Bingo!!!

12] Shutdown Nginx

$ sudo kill `cat /var/run/nginx/nginx.pid`

Telecom - Time to come

In next 3 - 5 years we will see a sea change in the role or service provided by Telecom operators. They will transform into ISPs, providing broadband / High speed data connectivity Over The Air to all the subscriber base. The mobile number portability will die an early death and IP Address portability will be default standard. Each subscriber will be assigned a unique IP address which will be means to communicate with him / her. All devices used by the subscriber will be NATed to the unique IP address. IPv6 seems to be the only viable option as of coming technology. And the IP assigning cost may be borne by the government. And the IP address will be issued along with the birth certificate.

HowTo Configure Port Based Virtual Host on Apache2

1] Change to root user to make changes

$ su -

2] Modify apache config file

# vi /etc/httpd/conf/httpd.conf

3] Locate the line which shows 'Listen 80' and add a line under it with the port number on which virtual host needs to run, in this example 8080.

Listen 8080

4] Then locate virtual host section in the config file which is usually at the end of the config file. And add new virtual host section as shown in the example below and save the file. Please m necessary changes in the below section as per your requirement.

# vhost

ServerAdmin webmaster@vhost.com
DocumentRoot /var/www/vhost
ServerName vhost.com
ErrorLog logs/vhost.com-error_log
CustomLog logs/vhost.com-access_log common


5] Above virtual host section we have defined html web page path as /var/www/vhost, so this directory has to exist along with the index.html page for apache to serve http request received on 8080.

6] Now check if apache config for errors

# /usr/sbin/apachectl -t

7] And if output say 'Syntax OK' then restart apache services

# service httpd restart

8] Now start your browser and open and bingo your Virtual Website is serving pages

http://ServerIP:8080

Replace ServerIP with the real ip address of your web server

Howto Disable SELINUX on CentOS 5.x / RHEL 5.x

1] Change to root user to make changes

$ su -

2] Check the status of SELINUX using following command

# sestatus
SELinux status: enabled

3] To disable SELINUX modify config file

# vi /etc/selinux/config

4] Search for the line 'SELINUX=enforcing' and modify this line as

SELINUX=disabled

5] Now save the file and reboot the system.

6] Once the system is restarted check the status of SELINUX run the command mentioned above in point 2 and now it should show SELINUX status as 'disabled'.

My search for free Push Mail Client for my E71

It was only when I brought recently launched (July 08) Nokia E71, I realised that Nokia has discontinued their support for BlackBerry and there was no BB client available for E71. And in One97 Communications, I was expected to be always accessible on my official emails. And then started my search to find free push client for my mobile.

My initial search on Google showed me few options to access our official emails on Google Apps. The options were Seven, Emoze, Mail For Exchange, Beta Nokia Messaging client, etc. First thing I tried was Mail For Exchange and educated immediately that Google Apps is not Exchanged based or compatible. Then it was the turn of the most promising client Seven. When I downloaded and installed Seven I was very exited and hopefull and after 5 - 6 days and few posting on the Seven mailing group and blogs, I found myself stuck in a no mans land. Every second person on web said Seven is the best and I looked like an idiot.

Then I tried Emoze and there I was exited to see my first push mails on my E71. And there was no stopping and I continued to trust and use Emoze and in between they came up with newer versions and I religiously upgrade the same on my mobile. With one version upgrade rollback I never faced any problem. Yesterday when I upgrade the firmware of my mobile I downloaded latest version of Emoze and i was surprised to find that now it supports only 1 email account and I need to upgrade Pro Version if I need mails from additional accounts.

Althought the cost is approximate Rs 700 per annum, but I decided to start my search again for free push client. This time I decided to use Google's Gmail for mobile Ver 2.0 a access mails. I was easy to get it installed and configure for my both Google App and gmail mails. But it did not take me long to realise that I am not getting any new mail alerts except a brief vibration. I searched everywhere to enable alert and then decided to ask google for an answer and got none. And so I started my search again and Nokia Messaging client was my next option. Although I avoid beta softwares but still decided to give Nokia Messaging client. And since the time my first mail rushed in on my mobile and I am totally impressed by this application. It has a very intelligent & impressive UI and it shows email status details on the mobile main screen. Only issue noticed by me was it s not possible to navigats to previous or next message by pressing NaviKey. Well it is too early to rate this product but overall a good product and shall put a post on the blog if I encounter anything interesting :)

Upgrading my Nokia E71 firmware to V200.21.118

Last night I decided to upgrade firmware of my Nokia E71 to the latest available V200.21.118 when I saw the very long list of changelog posted on few of Nokia / Symbian blogs. The improvement in WLAN, VOIP, Camera, Email functionality was of interest to me.

Well as everyone is aware firmware upgrade of any product is not for weak hearted and it is equally tough for Nokia phones. Before proceeding with firmware upgrade using Nokia Software Updater, you are required to make backup of our mobile data using Nokia PC Suite as all your data is wiped out when you flash the firmware of your mobile. Although all your data gets backup properly, but at the time of restore, PC Suite cannot restore back your most important of all the contact list. And Yes you also end up losing other important data like stored messages, calendar entries, notes etc.

It is a known issue and your only savior is Nokia's own tool 'Nokia_Contact_Transfer.exe'. But it is not so easy to locate this tool on Nokia site and I had to spends one precious night in November 08 just to locate it and all other tools I could lay my hands on were paid products. This tool is cool as it auto detects and shows all backup files stored on your desktop. And it helps you select correct stored backup file and recover / restore all your contacts data from the backup file. And this tool is so fast that you refuse to believe your eyes.

Anyway I am happy that I upgraded E71 and it was really worth the efforts I had to put in. And I do have a story to tell about my upgraded N71 but that will be coming tomorrow.