Category Archives: Servers

configure apache

Apache Active Directory Authentication

Overview

This tutorial provides an example of Apache Active Directory Authentication using the Authz LDAP module.
Apache and SSL settings are not in the scope of this tutorial.
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CentOS PostgreSQL Installation Tutorial – (Centos 6.x)

CentOS PostgreSQL Installation tutorial

CentOS PostgreSQL

centos postgresql :

PostgreSQL is a powerful, open source object-relational database system.
In the following tutorial I’ll show how to install PostgreSQL on your CentOS box

 

CentOS PostgreSQL Installation

We can install PostgreSQL in (at-least) two ways:

  • Using YUM
  • Compile from source

 

Install from repository

yum install postgresql-server
this will install the package postgresql-server, also: postgresql and postgresql-libs.
centos postgresql

centos postgresql

Install from source

If you want to install the latest version of PostgreSQL you should compile from source. it’s recommended for advanced users and one may argue it’s recommended too for production.

Anyway, this article from DigitalOcean covers this area well (and more). If you want to compile using source you better move to that article. If you prefer or installed using repository (yum), continue…

 

PostgreSQL Service

if you’ll try to start PostgreSQL using the service command, you will see an error tells you must init the db first and create the db files in: /var/lib//pgsql/data

posgresqlerror

so,

to init on centos postgresql service use:

service postgresql initdb

posgreinit

This created a data folder in /var/lib/pgsql. You can’t run this command again without deleting first this folder (and all your data).

Also, when you called the initdb command above from RedHat’s init script configured permissions on the database. These configuration settings are in the pg_hba.conf file inside the data folder.

By default all permissions are ‘Ident’,

pgsql-ident

means the only user that can get in initially is user “postgres”, so if you’ll try ‘psql’ from root you’ll get error:

psql: FATAL: Ident authentication failed for user “root”

If you want to login and use postgres with other users than `postgres` you can change the permissions method in pg_hba.conf. change from ‘ident’ to ‘md5’ is recommended.

If you want to use phpPgAdmin (described later) you should change from ‘Ident’ to ‘md5’ or else it won’t login to your system.

 

Set port and Listen Addresses

If you need to change the default port (5432 by default) and Listen Addresses (localhost by default), you can set those vars inside the postgresql.conf inside /var/lib/pgsql/data folder.

#listen_addresses = 'localhost'
#port = 5432

 

Start service

and then, to start on centos postgresql service use:

service postgresql start

postgrestart

to make centos postgresql load on boot use the chkconfig command as follows:

chkconfig postgresql on

 

and That’s it!

 

What next?

 

Managing from Command line

login to postgres

As I mentioned, default setup has ident authentication means the only user that can get in initially is user “postgres”, so if you haven’t changed permissions scheme you should su to postgres before.

to start ‘psql’ as postgres:

# change user to postgres
su - postgres
# start psql manager
psql
# CTRL + D twice to exit both psql and su.

# You can also short the two commands into:
# su postgres -c psql

Add (or create) a user with permission to specific database?

Read this great tutorial.

 

PhpPgAdmin

PostgreSQL visual interface similar to phpMyAdmin? – in short, if you know phpMyAdmin and want phpPgAdmin, you need to add the EPEL repositories, Apache (yum install httpd) and then install using:

If your permissions scheme is currently ‘Ident’ you might need to change that to ‘md5’ as PhpPgAdmin requires it.

yum install phpPgAdmin

Then visit in your browser: http://localhost/phpPgAdmin

centos phppgadmin
centos phppgadmin

Remote connection

Edit /etc/httpd/conf.d/phpPgAdmin.conf if you want to allow access remotly and restart httpd (service httpd restart).

do you use pgsql, postgres, root, administrator as login or even user without password?
if you do, set the $conf[‘extra_login_security’] entry to false in your et/phpPgAdmin/config.inc.php.

 

Change default Postgres user password

If you really want to use the “postgres” role, make sure you set it up a password and $conf[‘extra_login_security’] is false.

use the command:

passwd postgres

to change the system user password and

ALTER USER Postgres WITH PASSWORD 'password';

That alters the password for within the database. To change the password inside Postgresql. there is also short code (inside psql):

\password

Which will ask from you a new password to set.

 

 

Cheers!

Development Specialist, Artist and Activist
Personal Website
VMWare Workstation start on boot CentOS

CentOS Gunicorn installation instructions for newbies

centos gunicorn installation instructions

centos gunicorn

centos gunicorn : In this simple tutorial I’ll explain how to install and run Gunicorn python server on your CentOS machine.

This tutorial is meant for Centos 6.4 and above but it should work on any CentOS 6.x release.

 

What is gunicorn?

From: Gunicorn – Python WSGI HTTP Server for UNIX:

Gunicorn ‘Green Unicorn’ is a Python WSGI HTTP Server for UNIX. It’s a pre-fork worker model ported from Ruby’s Unicorn project. The Gunicorn server is broadly compatible with various web frameworks, simply implemented, light on server resources, and fairly speedy.

 

Installation

Python

before you going to install the centos gunicorn server you need to insure you have the python interperter installed (it should be, as it’s installed by default on the latest CentOS releases). to check that you have python use the command:

python

command not found of course means you need to install python now.

 

Install python

first make sure your have python installed. Simple as:

yum install python

test python by typing: “python” and you should see something similar to:

python

(Ctrl+D to exit)

 

Gunicorn

Next we need to install gunicorn. for this we have (as always) several choices.

1) Using YUM. I personally don’t recommend it. I know some are happy to use the system packaging management wherever possible, but as for python I don’t think it’s the way to go.

To install gunicorn using yum:

yum install python-gunicorn

2) Using easy_install. using easy_install is a better choice for my taste to install python packages. this is how you install gunicorn using easy_install, but I recommend installing gunicorn using PIP as I will show next…

yum install python-setuptools
easy_install gunicorn

3) Using PIP: This is my RECOMMENDED way of installing gunicorn. to install PIP you actually need easy_install so the commands are:

yum install python-setuptools
easy_install pip
pip install gunicorn

Virtualenv

I can’t recommend enough to start working with virtualenv from beginning. At some point in the future, if you are going to consist with python coding, you are going to use the ‘pip update’ command to update some or all your libraries and then expect your python application to stop working.

Python libraries, as any open source library, have the freedom to sacrifice backward compatibility for new features, performance or redesign.

Virtualenv is a python virtual environment tool to ensure that your python applications will work as expected as long you don’t deliberately update some or all of the dependency libraries for that virtual environment specifically.

To install virtualenv (and virtualenvwrapper) and learn the basics read this tutorial. then create your virtual environment and install gunicorn to that environment.

# after you've install pip, virtualenv and virtualenvwrapper
mkproject myapp
workon myapp
pip install gunicorn

 

Running Gunicorn

Basic usage:

$ gunicorn [OPTIONS] APP_MODULE

so for the following myapp.py file:

# -*- coding: utf-8 -

def app(environ, start_response):
    data = 'Hello, World!\n'
    status = '200 OK'
    response_headers = [
        ('Content-type','text/plain'),
        ('Content-Length', str(len(data)))
    ]
    start_response(status, response_headers)
    return iter([data])

just run:

gunicorn -w 4 myapp:app
# Sample output
[INFO] Arbiter booted
[INFO] Listening at: http://127.0.0.1:8000
[INFO] Worker spawned (pid: 16801)
[INFO] Worker spawned (pid: 16802)
[INFO] Worker spawned (pid: 16803)
[INFO] Worker spawned (pid: 16804)
centos gunicorn

centos gunicorn

This command starts gunicorn with 4 workers on port 8000. feel free to experiment and customize the command with additional parameters.

There also command line for using Django <1.4 and Paster. read more here.

Read more about configuring Gunicorn and configuration files.

 

Deploying Gunicorn

on deployment, It’s strongly recommended to use Gunicorn behind a proxy server.

nginx

I personally prefer nginx but it’s not your only choice.

If you want to install nginx on your CentOS machine follow this installation instructions.
use this script (at github) to configure your nginx to pass request to the gunicorn process

 

Monitoring and Logging

Usally you’d want the gunicorn to be run in the background, load on boot and restart on errors. you want also the ability to monitor that process.

There are several tools for that.job, including: Supervisord, Gafferd, runit and many more…  choose what fits you best. here you have examples for monitoring gunicorn using those tools.

 

That it. enjoy playing with your centos gunicorn setup.

 

Development Specialist, Artist and Activist
Personal Website
cento tomcat

CentOS Tomcat server installation is easy!

CentOS Tomcat installation

CentOS Tomcat

centos tomcat

“Apache Tomcat is an open source software implementation of the Java Servlet and JavaServer Pages technologies. The Java Servlet and JavaServer Pages specifications are developed under the Java Community Process.” from Tomcat homepage.

 

Prerequisities

  • CentOS 6.x (I haven’t tested this on older versions but it should probably work as well) 

Check your Java installation

before we’ll continue the installation of Tomcat, the JDK (Java Development Kit) should be installed on your CentOS machine. to check for Java support use the command:

java -version

javanotfound

if bash returns ‘command not found‘ then continue to the next step and install the JDK, else skip the step and continue to Tomcat server installation.

 

Install Java Development Kit (JDK)

To install the jdk we have 2 options:

  1. Install OpenJDK – Using YUM.
  2. Install Oracle JDK – Install manually.

I’ll explore both:

Option 1: Install Open-JDK using YUM

For beginners and testing purposes you should go with this option.

Why should I use the Oracle JDK over the OpenJDK, or vice-versa? [closed]

The command to install JDK using YUM is very simple:

yum install java

yuminstall java

  • Note: use sudo if you are not logged-in with root.
  • the command will install the latest jdk (1.7 as for this date). If you want to install older version use the full name (search using: $ yum search jdk)yum-search-jdk
    You can see you can install the 1.6 version by typing: yum install java-1.6.0

Check you have installed it right:

javafound

 

Option 2: Install JDK manually

Download your required JDK here.

Note: I can’t give you an WGET command to download, because you need to Accept License Agreement before downloading any file.

You can download and install using the RPM or the tar.gz (both with x86 or x64) on your CentOS machine:

downloadjava

 

 

In case of our CentOS we can download and install the .rpm file or the .tar.gz file.

RPM can be installed ONLY by the root.
TAR.GZ can be installed be any user on the computer.

 

Option A: Install using .rpm

make sure to uninstall older installations (if any):

rpm –e <package name>

To install the jdk using the downloaded rpm use the rpm command:

rpm –ivh jdk-7u45-linux-x64.rpm

If you just want to upgrade a package you’ve already installed use the -Uvh parameter.

rpm –Uvh jdk-7u45-linux-x64.rpm

Delete the .rpm file if you want to save disk space.

Read more about installation of Oracle Java on Centos here on ItekBlog

 

Use alternatives :

alternatives –install /usr/bin/java java /usr/java/latest/jre/bin/java 20000
alternatives –install /usr/bin/javaws javaws /usr/java/latest/jre/bin/javaws 20000

alternatives

and config your default jdk (if you have more then one) using:

using:

alternatives –config java

alternatives-config

 

Test your environment

Just as in the first step: type java -version to see if your have jdk installed.

oraclejavaversion

 

Option B: Install using tar.gz

The advantage of tar.gz installation of the JDK is that we can able to install multiple version of java if required.

The archive can be installed by anyone (not only root users), in any location that you can write to. However, only the root user can install the JDK into the system location.

You need to unpack the .tar.gz file (using tar -xzf) into the  the location where you would like the JDK to be installed.

Unpack the tarball and install the jdk:

tar zxvf jdk-7u<version>-linux-i586.tar.gz

Delete the .tar.gz file if you want to save disk space.

 

Use alternatives :

alternatives –install /usr/bin/java java /path/to/jdk1.7.0_45/bin/java 2
alternatives –config java

read more about installation of jdk in the oracle documentation.

for extended installation tutorial read this post by adam in this blog.

 

JDK 1.6 vs JDK 1.7

read more on What is the difference between jdk 1.6 and 1.7 ?

 

Environment Variables

1
JAVA_HOME

 is a 

1
environment

 variable (in Unix terminologies), or a PATH variable (in Windows terminology) you need to create to point to where Java is installed. ($JAVA_HOME/bin/java should execute the Java runtime).

Why doesn’t the Java SDK installer set JAVA_HOME?

To set it for your current session type at bash:

export JAVA_HOME=/usr/java/jdk1.7.0_05
export PATH=$PATH:$JAVA_HOME/bin

To set the JAVA_HOME permanently we need to add the commands to the ~/.bash_profile file of the user.
We can also add it /etc/profile and then source it to give to all users.

 

Test Environment Variables

use the echo command to check you’ve configured the variables:

echo $JAVA_HOME
echo $PATH

echovars

 

Installing Tomcat

After we have java installed and tested we can continue to the installation of the Tomcat server.

Download Tomcat

Since Apache Tomcat is distributed as binaries, all you have to do is to download it and start it.

Download apache-tomcat-x.x.xx.tar.gz (latest version or any) from Apache Tomcat Homepage

I’ll go with the tomcat 8 – tar.gz package.

centos tomcat

centos tomcat

and using command:

cd /usr/share
wget http://apache.spd.co.il/tomcat/tomcat-8/v8.0.0-RC10/bin/apache-tomcat-8.0.0-RC10.tar.gz

tomcat-wget

verify and extract the download using::

md5sum apache-tomcat-8.0.0-RC10.tar.gz
tar xvzf apache-tomcat-8.0.0-RC10.tar.gz

and I have a /usr/share/apache-tomcat-8.0.0-RC10 folder now.

 

Test Tomcat server

Tomcat by default start on port 8080 you can start the server now by typing at bash:

cd apache-tomcat-8.0.0-RC10
./bin/startup.sh

tomcat-start

 

Now Access the tomcat by connecting your server with a web browser on port 8080.

http://localhost:8080

tomcat

If you cannot access the above Tomcat page, make sure to stop iptables (since CentOS has iptables on by default set to block the Tomcat’s default listening port 8080).

service iptables stop

to permanently disable iptables (NOT RECOMMENDED AT ALL) use:

chkconfig iptables off

Change the Tomcat server port

Locate server.xml in {Tomcat installation folder}/conf/ which is at /usr/share/apache-tomcat-8.0.0-RC10/conf in our case

Find the following:

 <!-- Define a non-SSL HTTP/1.1 Connector on port 8180 -->
    <Connector port="8080" maxHttpHeaderSize="8192"
               maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
               enableLookups="false" redirectPort="8443" acceptCount="100"
               connectionTimeout="20000" disableUploadTimeout="true" />

and change the 8080 port to your required port.

 

Start on boot

To start the tomcat service on system boot create the file /etc/init.d/tomcat8 (I am using vi /etc/init.d/tomcat8) and fill it with:

#!/bin/bash 
# description: Tomcat Start Stop Restart 
# processname: tomcat 
# chkconfig: 234 20 80 
JAVA_HOME=/usr/java/jdk1.7.0_05 
export JAVA_HOME 
PATH=$JAVA_HOME/bin:$PATH 
export PATH 
CATALINA_HOME=/usr/share/apache-tomcat-8.0.0-RC10
 
case $1 in 
start) 
sh $CATALINA_HOME/bin/startup.sh 
;; 
stop) 
sh $CATALINA_HOME/bin/shutdown.sh 
;; 
restart) 
sh $CATALINA_HOME/bin/shutdown.sh 
sh $CATALINA_HOME/bin/startup.sh 
;; 
esac 
exit 0

Now set the permissions on the file and the catalina.sh file:

chmod a+x /etc/init.d/tomcat8
chmod a+x /usr/share/apache-tomcat-8.0.0-RC10/bin/catalina.sh

to start/stop/restart the service use:

service tomcat8 start
service tomcat8 restart
service tomcat8 stop

to start the service on boot use:

chkconfig --add tomcat8
chkconfig tomcat8 on

to disable it later you can use off instead of on:

chkconfig tomcat8 off

 

 

That’s it! you have your CentOS Tomcat server working and runing… 

Development Specialist, Artist and Activist
Personal Website
G-WAN

CentOS G-WAN server installation instructions

CentOS G-WAN Server

CentOS G-WAN server

G-WAN is a web server with scripts in Asm, C, C++, C#, D, Go, Java, Javascript, Lua, Objective-C, Perl, PHP, Python, Ruby and Scala.

G-WAN better uses CPU Cores
to make the Internet of Things
fly thousand times higher !

Leverage legacy servers and
low-consumption CPUs to
do more with less!

G-WAN works best on Linux distributions like Debian or CentOS, both of which offer ‘Desktop’ and ‘Server’ flavors.

 

CentOS G-WAN server installation instructions

CentOS G-WAN installation instructions

 

Installation

choose a location for your installation. for demonstration purposes we’ll install G-WAN to /opt

cd /opt
wget http://gwan.com/archives/gwan_linux64-bit.tar.bz2
tar -xjf gwan_linux64-bit.tar.bz2; cd gwan_linux64-bit
sudo ./gwan
centos g-wan

centos g-wan

use the 32bit version instead (http://gwan.com/archives/gwan_linux32-bit.tar.bz2) if you need.

Test

Then, type http://localhost:8080/ in your browser

centos g-wan

centos g-wan server default homepage

and play with the/gwan/.../csp samples.

 

Programming Languages

If you want to install more Programming Languages read the FAQ – Setup of Programming Languages

To install all 15 languages using the bash script donated by generous user on many Linux distributions (Debian, LinuxMint, CentOS, Fedora, RedHat, Manjaro, Arch Linux and Bridge) use:

cd /opt
wget http://www.as2.com/linux/tools/G-WAN_full-install.tar.bz2
tar -xjf G-WAN_full-install.tar.bz2
./G-WAN_full-install

The installation menu is available in English, German, French and Spanish!

 

Service mode

To start G-WAN as a service (make it start automatically at boot time) use this instructions

with one exception for CentOS in the manual:

instead of:

sudo update-rc.d gwan defaults 95 5

use:

sudo chkconfig gwan on

and you don’t need to restart.

 

What’s next?

check the API and Frequently Asked Questions.

Stackoverflow lists many more examples and will let you search for replies to common questions.

 

And that’s it. you have G-WAN server.

Development Specialist, Artist and Activist
Personal Website
how to speed website

How to speed up website load time

How to speed up website load time

How to speed up website load time is important question for those that performance matters to them.

Nobody Likes a Slow Website!

 

Overview

How to speed up website?

Website optimization is a required step for production, and when is automated when possible correctly it can help you deliver your website as fastest as possible without compromising on development comfortability and code readability.

 

Test your website load time speed

How to speed up website question could be answered for your case better if you’ll use a website speed test tools. There several good websites load time speed tests available online for free. check out pingdom website speed test, Google PageSpeed tools. this are very good tools which also gives you important and valuable information and tips to speed up your website.

 

pingdom

You can also check: WebPagetest, GTmetrix or PageScoring Website Speed Test.

Some of them rates your website and/or explain what could be done to make your site faster. you can learn also a lot from loading time graphs.collect information from all the above to optimize your website to maximum.

  • If it takes more then 10 seconds for your website to load. you are doing a very bad job optimizing your website (if at all).
  • If your page load time takes several seconds then you’re ok (but you can do better then that!).
  • if your page load time takes up to two seconds then your site is in very good shape!
  • if your page load time takes less then a second then your site is sooooo fast!! and you are doing a excellent job!

if your score is bad.. continue reading How to speed up website

 

How to speed up website load time

So, how to speed up your website load time?

You can do that using several tweaks.. one at a time…

 

1. learn the waterfall. where are your bottom neck ?

Use the mentioned websites speed test graphs to learn what are the slowest parts of your website and start with them. does the problem is with your webserver or maybe the infrastructure?

How to speed up website ? Does your static files load time is the problem?

And maybe it is the dns? processing request? loading the images? loading the scripts? maybe you have bad requests?

This extreme powerfull tool will help you learn your weaks and strongs.

how to speed website

how to speed website

2. Minimize redirects

If your website on load check if it’s mobile or not, then it redirect to another page when checks the language and then redirects to another page who check the cookies and then redirect… well you’ve got the idea. Bad design pattern!

Minimize redirects!

 

3. Browser caching

Set up your server to return Expire and Cache-Control headers with static files. Setup you expire date to be within week or more is a very good timeframe (depend on how frequently you update your website static files you can setup the expire date as required).

 

4. use CDN (if possible)

Content Delivery Network (CDN) can be an important tool in achieving decent page load and web application speeds. Providers such as AkamaiEdgeCast, Amazon (CloudFront), Rackspace (CloudFiles), Google (PageSpeed) and Microsoft (Azure CDN) are providing the means to distribute your content to locations geographically closer to your customers/users, which improves the responsiveness of the application or website.

 

5. put cache server between your server and your client when possible

Although using a CDN can help with page load speeds, a CDN is not always the best solution in terms of Cost–benefit.

when configuring a cache server before your website server, and no matter if it’s apache, tomcat, gunicorn or any other html generator you can boost up clients page load dramatically.

 

caching the compiled html pages is very important speed tweak. if you have any static and/or low-rate updated pages with no problem if some users will not see the lastest updates of the html when it changes (until cache reloads).. check varnish-cache or squid-cache or nginx (with HttpProxy module) or Apache with mod_proxy.

You should think of your webapp as in several seperate layers. where one layer could answering html requests and other serving your static files. always try to find the suitable tool for this mission in terms of speed (and taste). consider serving your static files (those not on CDN) using the fastest web server for static files you can find.

 

6. Minify

A very important stage is to minify data.

  • Minify CSS files for production! there are many simple gui or command tools to do that..
    if you are using LESS, SASS or other, Never compile on client side! compiler only on server side and setup your compiler to minify results.
  • Minify your JS files. if possible, insert them as scripts into the html, or better, minify and join them inside when processing the html (But don’t forget to use Cache server!).
    If you’re using Coffee-script and template engine it should be easier as you can compile the ,coffee file to minified version and include it within your template.
  • Minify HTML. if you have static html files use command or gui tool. if you have more advanced server like python or ruby – minify them before sumbit.
  • If your template engine support preprocessors. use them to minify HTML (and everything other you can). if not – use a library (if possible).

 

7. GZip

Configure you webserver (nginx, apache,etc)  to GZip response.

Set the Vary header (Vary: Accept-Encoding header) correctly for Internet Explorer.

 

8. Caching data

If you have data you can cache in memory for your application server – DO IT.

Use Redis, memcached or any other tool you find is suitable.

It can be small data (like the number of your followers you’ve just counted from facebook, twitter and youtube JSON calls) or the Entire processed HTML.

Put expire time for each resource on your store as needed.

 

 

How to speed up website

‘ How to speed up website ‘ tutorial ends here.

hope you’ll have fun optimizing your website and now you now few important tips on How to speed up website

Using those steps I’ve managed to reduced my website load time from several seconds to only 1-2 seconds (and sometimes less then second). It’s was worth the effort!!

 

Good day (or night),

Development Specialist, Artist and Activist
Personal Website

Django CentOS 6.4 installation instructions for noobs.

Django Centos 6.4 installation instructions for noobs.

So you want to build your first django centos 6.4 based web site? This is quite easy to install and configure. I’ll cover how to install Python/Django on your centos.

Django Centos

Prerequisite

  • CentOS 6.4 (For the matter of fact, this tutuorial is good for all the CentOS 6.x series)
  • Apache (httpd)

 

What is Python?

Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Its syntax is said to be clear and expressive.” from Wikipedia.

Visit http://www.python.org/

 

What is Django?

“Django is a high-level Python Web framework that encourages rapid development and clean, pragmatic design.” from https://www.djangoproject.com/

Installing Python

Prerequisites

you may need the EPEL repositories for Centos.

cd /opt/
wget http://mirrors.nl.eu.kernel.org/fedora-epel/6/i386/epel-release-6-8.noarch.rpm
rpm -Uvh epel-release-6-8.noarch.rpm
rm epel-release-6-8.noarch.rpm -f

 

Installation Process

Simple as:

yum install python

test python by typing: “python” and you should see something similar to: (CTRL+D to exit)

At the time of writing (September 30 2013), the version of python@EPEL is 2.6.6

Django works with any Python version from 2.6.5 to 2.7. It also features experimental support for versions 3.2 and 3.3. All these versions of Python include a lightweight database called SQLite so you won’t need to set up a database just yet unless you need other SQL

 

Installing SQL

Django works with several DB engines. for simplicity, Install SQLite:

yum install sqlite

If you need other SQL Server else then SQLite,  you can follow:
MySQL/MongoDB/CouchDB on RHEL/Centos 6.3
If you don’t need SQL and you installed Python 2.5 or later, you can skip this step for now.

 

 

 

 

Installing Django

You can install using EPEL repositories any yum (like in the old article I wrote), but I recommend to use the easy_install method from the python-setuptools package, which I’ll show next:

yum install python-setuptools
easy_install django

 

Testing Django

Test Django by typing python on your command and then:

import django
print django.get_version()

python-django-1.5.4

As you can see, the RPM version is version 1.5.4, while the current release in the EPEL version is 1.3.1. Internationalization: in template code is not available in 1.3.1 for example but only from Django 1.4

 

 

Creating Project

From the command, cd into a directory where you’d like to store your app, then run the following command:

django-admin.py startproject mysite
cd mysite

 Note: if you are installing Django using EPEL repos, the command will be django-admin and not django-admin.py.

Starting Server

python manage.py runserver

You’ve started the Django development server, a lightweight Web server – easier to startwithout having to deal with configuring a production server — such as Apache — until you’re ready for production.

Browse to http://127.0.0.1:8000/ with your Web browser. You’ll see a “Welcome to Django” page. It worked!

To change port:

python manage.py runserver 8080

If you need to start the server to answer not only locally, use:

python manage.py runserver 0.0.0.0:8000

 

Remember: Apache loads Django environment when starting and keep running it even when source is changed! I suggest you to use Django ‘runserver’ (which automatically restarts on source code changes) in development sessions, unless you need some Apache-specific features.

 

Configure more…

Config Database

Edit mysite/settings.py. It’s a normal Python module with module-level variables representing Django settings.

Help here.

 

Django using Apache

To run your Django application inside apache – use either mod_python or mod_wsgi, Support for mod_python will be deprecated in a future release of Django. If you are configuring a new deployment, you are strongly encouraged to consider using mod_wsgi or any of the other supported backends.

 

OPTION A: Install mod_python (NOT recommended)

For this to work, you must have apache installed and configured.

yum install mod_python

python using mod_python

you need to configure you apache/VirtualHost to:


    AddHandler mod_python .py
    PythonHandler mod_python.publisher | .py
    AddHandler mod_python .psp .psp_
    PythonHandler mod_python.psp | .psp .psp_
    PythonDebug On

 

Testing mod_python

Create a ‘test.py’ file in your apache server. put inside:

<% req.write("Hello World!") %>

and browse to www.your.server/test.py and you should see the “Hello World!” there.

Django using mod_python

Edit your httpd.conf file:


<Location "/mysite/">
    SetHandler python-program
    PythonHandler django.core.handlers.modpython
    SetEnv DJANGO_SETTINGS_MODULE mysite.settings
    PythonOption django.root /mysite
    PythonDebug On
</Location>

read more…

 

 

Option B: Install mod_wsgi (RECOMMENDED)

Deploying Django with Apache and mod_wsgi is the recommended way to get Django into production.

yum install mod_wsgi

 

to use mod_wsgi, create an apache folder inside your project and create a django.wsgi file:

import os, sys
sys.path.append('/var/www/django')
sys.path.append('/var/www/django/mysite')
os.environ['DJANGO_SETTINGS_MODULE'] = 'mysite.settings'

import django.core.handlers.wsgi

application = django.core.handlers.wsgi.WSGIHandler()

 

and configure your apache with:

<VirtualHost *:80>

ServerName www.example.com
ServerAlias www.example.com
WSGIScriptAlias / /var/www/django/mysite/apache/django.wsgi

# Alias /robots.txt /var/www/django/mysite/static/robots.txt
# Alias /favicon.ico /var/www/django/mysite/static/favicon.ico
Alias /static/admin/ /usr/lib/python2.6/site-packages/django/contrib/admin/media/
Alias /static/ /var/www/django/mysite/static/
Alias /media/ /var/www/django/mysite/media/

<Directory /var/www/django/mysite>
Order allow,deny
Allow from all
</Directory>

<Directory /var/www/django/mysite/media>
Order deny,allow
Allow from all
</Directory>

<Directory /var/www/django/mysite/static>
Order deny,allow
Allow from all
</Directory>
</VirtualHost>

 

read more on: multiple django sites with apache & mod_wsgi

 

 

That’s it!

 

You’ve Python / Django installed on your Centos 6.4 and a new project template waiting for you to work on.

 

Continue reading…

* this article is an edited version of an older article.

Development Specialist, Artist and Activist
Personal Website

gevent CentOS 6.x Installation Guide

gevent CentOS 6.x Installation Guide

gevent CentOS 6.x Installation Guide

Installation

Requirments

  • yum install python python-devel
  • yum install libevent-devel

 

Install Setuptools

install python-setuptools (for easy_install)

yum install python-setuptools

Install greenlet

Install greenlet:

easy_install greenlet

Install gevent

There are several ways to install gevent:

using easy_install (recommended)

easy as:

easy_install gevent

centos gevent

from source

You need wget to download source:

yum install wget

Now, installing gevent: (Check here for the latest package)

cd /tmp wget http://pypi.python.org/packages/source/g/gevent/gevent-0.13.8.tar.gz tar -xvzf gevent-0.13.8.tar.gz cd gevent-0.13.8 python setup.py install

U may need to add –no-check-certificate to the wget if something is wrong.

from GitHub

You can also install gevent from github using pip.

Test

to test simply run in bash:

python

and then:

import gevent

if no error found, you have installed it correctly python-import-gevent

First App

Example taken from the community documentation:

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from gevent.wsgi import WSGIServer
 
def application(environ, start_response):
    status = '200 OK'
    body = '<p>Hello World</p>'
 
    headers = [
        ('Content-Type', 'text/html')
    ]
 
    start_response(status, headers)
    return [body]
 
WSGIServer(('', 8000), application).serve_forever()
from gevent.wsgi import WSGIServer

def application(environ, start_response):
    status = '200 OK'
    body = '<p>Hello World</p>'

    headers = [
        ('Content-Type', 'text/html')
    ]

    start_response(status, headers)
    return [body]

WSGIServer(('', 8000), application).serve_forever()

copy the example into a file (server.py for ex), and start the server by:

python server.py

and that’s it! browse to the machine on port 8000 using something like this:

http://[ip of the machine]:8000

gevent-working

What’s next..?

 

Production

In production you can host your gevent after several WSGI server racks like: Gunicorn, Circus, Meinheld, uWSGI, etc..

Gunicorn is the most common WSGI server to host gevent applications. one benchmark shows that Circus is faster then Gunicorn. other tested uWSGI vs Gunicorn and found that uWSGI is faster.

recommend you run them behind a reverse proxy such as nginx. Additional advantages of running them behind a reverse proxy include improved handling of slow clients and bad HTTP requests

 

SocketIO

You need socketio? you may want to install it:

easy_install gevent-socketio

 

Read more…

 

need microframework? (flask/bottle)?

You can use a python web framework on top of gevent.

 

Development Specialist, Artist and Activist
Personal Website

WordPress SSL Encryption using Apache and mod_ssl

Overview

WordPress SSL Encryption has several options so you can encrypt just the Log-in page, the entire Admin area or the entire WordPress instance.
Continue reading

Django Centos 6 Beginners Installation Guide

NOTE: This article was rewritten for CentOS 6.4. please read the updated post.

 

Django Centos 6

So you want your first django centos based web site? This is quite easy to install and configure. I’ll cover how to install Python/Django on your centos.

Django Centos

Prerequisite

  • Centos 6.x
  • Apache (httpd)

 

What is Python?

Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Its syntax is said to be clear and expressive.” from Wikipedia.

Visit http://www.python.org/

 

What is Django?

“Django is a high-level Python Web framework that encourages rapid development and clean, pragmatic design.” from https://www.djangoproject.com/

Installing Python

Prerequisites

you may need the EPEL repositories for Centos.

cd /opt/
wget http://mirrors.nl.eu.kernel.org/fedora-epel/6/i386/epel-release-6-8.noarch.rpm
rpm -Uvh epel-release-6-8.noarch.rpm
rm epel-release-6-8.noarch.rpm -f

 

Installation Process

Simple as:

yum install python

test python by typing: “python” and you should see something similar to:

As for this time being of writing (June 18 2012), the version of python@EPEL is 2.6.6

Django works with any Python version from 2.6.5 to 2.7. It also features experimental support for versions 3.2 and 3.3. All these versions of Python include a lightweight database called SQLite so you won’t need to set up a database just yet unless you need other SQL

 

Installing SQL

If you need other SQL Server else then SQLite,  you can follow:
MySQL/MongoDB/CouchDB on RHEL/Centos 6.3
If you don’t need SQL and you installed Python 2.5 or later, you can skip this step for now.

 

 

 

 

Installing Django

yum install Django

 

Testing Django

Test Django by typing python on your command and then:

import django
print django.get_version()

As you can see, the RPM version is version 1.3.1, while the current release version is 1.4.1. while you are not too far behind using EPEL, you won’t get to play with the last options. Internationalization: in template code is not available in 1.3.1 for example but only from Django 1.4

 

 

Creating Project

From the command, cd into a directory where you’d like to store your app, then run the following command:

django-admin startproject mysite
cd mysite

 

Starting Server

python manage.py runserver

You’ve started the Django development server, a lightweight Web server – easier to startwithout having to deal with configuring a production server — such as Apache — until you’re ready for production.

Browse to http://127.0.0.1:8000/ with your Web browser. You’ll see a “Welcome to Django” page. It worked!

To change port:

python manage.py runserver 8080

If you need to start the server to answer not only locally, use:

python manage.py runserver 0.0.0.0:8000

 

Remember: Apache loads Django environment when starting and keep running it even when source is changed! I suggest you to use Django ‘runserver’ (which automatically restarts on source code changes) in development sessions, unless you need some Apache-specific features.

 

Configure more…

Config Database

Edit mysite/settings.py. It’s a normal Python module with module-level variables representing Django settings.

Help here.

 

Django using Apache

To run your Django application inside apache – use either mod_python or mod_wsgi, Support for mod_python will be deprecated in a future release of Django. If you are configuring a new deployment, you are strongly encouraged to consider using mod_wsgi or any of the other supported backends.

 

Install mod_python

For this to work, you must have apache installed and configured.

yum install mod_python

python using mod_python

you need to configure you apache/VirtualHost to:


    AddHandler mod_python .py
    PythonHandler mod_python.publisher | .py
    AddHandler mod_python .psp .psp_
    PythonHandler mod_python.psp | .psp .psp_
    PythonDebug On

 

Testing mod_python

Create a ‘test.py’ file in your apache server. put inside:

<% req.write("Hello World!") %>

and browse to www.your.server/test.py and you should see the “Hello World!” there.

Django using mod_python

Edit your httpd.conf file:


<Location "/mysite/">
    SetHandler python-program
    PythonHandler django.core.handlers.modpython
    SetEnv DJANGO_SETTINGS_MODULE mysite.settings
    PythonOption django.root /mysite
    PythonDebug On
</Location>

read more…

 

 

Install mod_wsgi

Deploying Django with Apache and mod_wsgi is the recommended way to get Django into production.

yum install mod_wsgi

 

to use mod_wsgi, create an apache folder inside your project and create a django.wsgi file:

import os, sys
sys.path.append('/var/www/django')
sys.path.append('/var/www/django/mysite')
os.environ['DJANGO_SETTINGS_MODULE'] = 'mysite.settings'

import django.core.handlers.wsgi

application = django.core.handlers.wsgi.WSGIHandler()

 

and configure your apache with:

<VirtualHost *:80>

ServerName www.example.com
ServerAlias www.example.com
WSGIScriptAlias / /var/www/django/mysite/apache/django.wsgi

# Alias /robots.txt /var/www/django/mysite/static/robots.txt
# Alias /favicon.ico /var/www/django/mysite/static/favicon.ico
Alias /static/admin/ /usr/lib/python2.6/site-packages/django/contrib/admin/media/
Alias /static/ /var/www/django/mysite/static/
Alias /media/ /var/www/django/mysite/media/

<Directory /var/www/django/mysite>
Order allow,deny
Allow from all
</Directory>

<Directory /var/www/django/mysite/media>
Order deny,allow
Allow from all
</Directory>

<Directory /var/www/django/mysite/static>
Order deny,allow
Allow from all
</Directory>
</VirtualHost>

 

read more on: multiple django sites with apache & mod_wsgi

 

 

That’s it!

 

You’ve Python / Django installed on your Centos 6.3 and a new project template waiting for you to work on.

 

Continue reading…

* this article is an edited version of an older article.

Development Specialist, Artist and Activist
Personal Website
configure apache

Apache Variables using system variables or mod_macro

Apache Variables

Apache Variables are not supported by defaultby apache but you can do two things to achieve this functionality::

  • Option 1 – Use system variables
  • Option 2 – Use mod_macro

Applicable to

  • Centos 6.x

This article was written with instructions for Centos 6.x, but the concept applies any distibution.

 

Option 1 – System Variables

Add variables in init script

To set environment variables in your Apache init script (/etc/init.d/httpd) before the line that calls httpd. For example, add:

MYVAR=value

Better would be to store all the variables in an external file, for example you can call it: /etc/httpd/conf/vars.txt and add to it all your variables:

MYAPP=/path/to/dir
BAR=/path/to/dir

and then include these into your Apache init.d script with:

. /etc/httpd/conf/vars.txt

you can also reload the file into memory by using the last command on shell.

to check that the variables added to your system variables use the set command:

set

Using inside configuration

Variables can be used in the configuration like so:

${MYVAR}

The variables can be used anywhere.

You can pass the variable into your CGI scripts and SSI pages using mod_env by adding to your confs:

PassEnv LD_LIBRARY_PATH

 

Option 2 – mod_macro

You can use apache Variables as functions using mod_macro extension,

mod_macro enables you to create macro functions with variables like:

<Macro VHost $host $port $dir>
  Listen $port
  <VirtualHost *:$port>

    ServerName $host
    DocumentRoot $dir

    <Directory $dir>
      # do something here...
    </Directory>

    # limit access to intranet subdir.
    <Directory $dir/intranet>
      order deny,allow
      deny from all
      allow from 10.0.0.0/8
    </Directory>
  </VirtualHost>
</Macro>

## Use of VHost with different arguments.

Use VHost www.apache.org 80 /projects/apache/web
Use VHost www.perl.com 8080 /projects/perl/web
Use VHost www.ensmp.fr 1234 /projects/mines/web

* example taken from here.

Prerequisites for mod_macro

  • The scripts in the article uses wget: yum install wget
  • apxs: yum install httpd-devel.i386
  • apache version 2.3

check your apache version using:
httpd -v

centos repository have apache 2.2.15, so you’ll need to compile newer version from source which is out of the bounds of this article. if you have later version of apache you can still use mod_macro which is better solution (for me) over system variables

 

mod_macro

to download and install mod_macro type:

cd /tmp
wget http://people.apache.org/~fabien/mod_macro/mod_macro-latest.tar.gz
tar xzvf mod_macro-1.2.1.tar.gz
apxs -cia mod_macro-1.2.1/mod_macro.c

Update 1.2.1 if wget returns newer version.

read more information and view demonstration code of how to use this extension check: http://www.cri.ensmp.fr/~coelho/mod_macro/

 

That’s it! select the way appropriate for your apache variables…

Development Specialist, Artist and Activist
Personal Website

Load Balancing SSH Connections using Pen on CentOS Linux

Overview

Load Balancing SSH Connections using Pen, a load balancer for “simple” tcp based protocols such as http or smtp.
It allows several servers to appear as one to the outside and automatically detects servers that are down and distributes clients among the available servers. This gives high availability and scalable performance.

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