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Samba: How to share files for your LAN without user/password

admin — Fri, 06 Jan 2012 10:57:17 +0000

This tutorial will show how to set samba to allow read-only file sharing for your LAN computers as guest (without be prompted for a password).

Because users won’t be prompted for a user/password, this tutorial is meant to be installed in a LAN where all host are to be trusted.

There is many advantages of sharing files in a LAN. For instance, when you have a multimedia box (playing music, movies….) it is great to be able to access the music on that box from any machines in your LAN.

Let’s get started. In the first place, you need to have samba installed.

$sudo apt-get install samba

Because we are going to make samba security insecure, make sure only your local network can access samba service. To do so, open and edit/etc/samba/smb.conf

$sudo vi /etc/samba/smb.conf

and set interfaces to lo and your local network interface. In my case: eth1.

interfaces = lo eth1
bind interfaces only = true

Now, it is time to smoothen samba default security by changing the security variable: security and make sure it is set to share instead ofuser and that guest account is enabled:

security = share
...
...
guest account = nobody

Now, we can create a share to be accessible to guest users:

[Guest Share]
        comment = Guest access share
        path = /path/to/dir/to/share
        browseable = yes
        read only = yes
        guest ok = yes

You can now test that your configuration is good using testparm:

$ testparm

If everything is fine, it is time to reload samba service to have your new configuration taken into account:

$sudo /etc/init.d/samba reload

That’s it, anybody in your LAN can now access your share.

Create daemons in PHP

admin — Mon, 26 Apr 2010 04:15:02 +0000

Everyone knows PHP can be used to create websites. But it can also be used to create desktop applications and commandline tools. And now with a class called System_Daemon, you can even create daemons using nothing but PHP. And did I mention it was easy?

What is a Daemon?

A daemon is a Linux program that run in the background, just like a ‘Service‘ on Windows. It can perform all sorts of tasks that do not require direct user input. Apache is a daemon, so is MySQL. All you ever hear from them is found in somewhere in /var/log, yet they silently power over 40% of the Internet.

You reading this page, would not have been possible without them. So clearly: a daemon is a powerful thing, and can be bend to do a lot of different tasks.

Why PHP?

Most daemons are written in C. It’s fast & robust. But if you are in a LAMP oriented company like me, and you need to create a lot of software in PHP anyway, it makes sense:

Reuse & connect existing code Think of database connections, classes that create customers from your CRM, etc.
Deliver new applications very fast PHP has a lot of build in functions that speed up development greatly.
Everyone knows PHP (right?) If you work in a small company: chances are there are more PHP programmers than there are C programmers. What if your C guy abandons ship? Admittedly it’s a very pragmatic reason, but it’s the same reason why Facebook is building HipHop.

Possible use cases

Website optimization If you’re running a (large) website, jobs that do heavy lifting should be taken away from the user interface and scheduled to run on the machine separately.
Log parser Continually scan logfiles and import critical messages in your database.
SMS daemon Read a database queue, and let your little daemon interface with your SMS provider. If it fails, it can easily try again later!
Video converter (think Youtube) Scan a queue/directory for incoming video uploads. Make some system calls to ffmpeg to finally store them as Flash video files. Surely you don’t want to convert video files right after the upload, blocking the user interface that long? No: the daemon will send the uploader a mail when the conversion is done, and proceed with the next scheduled upload

Deamons vs Cronjobs

Some people use cronjobs for the same Possible use cases. Crontab is fine but it only allows you to run a PHP file every minute or so.

What if the previous run hasn’t finished yet? Overlap can seriously damage your data & cause siginificant load on your machines.
What if you can’t afford to wait a minute for the cronjob to run? Maybe you need to trigger a process the moment a record is inserted?
What if you want to keep track of multiple ‘runs’ and store data in memory.
What if you need to keep your application listening (on a socket for example) Cronjobs are a bit rude for this, they may spin out of control and don’t provide a

framework for logging, etc. Creating a daemon would offer more elegance & possibilities. Let’s just say: there are very good reasons why a Linux OS isn’t composed entirely of Cronjobs

How it works internally

(Nerd alert!) When a daemon program is started, it fires up a second child process, detaches it, and then the parent process dies. This is called forking. Because the parent process dies, it will give the console back and it will look like nothing has happened. But wait: the child process is still running. Even if you close your terminal, the child continues to run in memory, until it either stops, crashes or is killed.

In PHP: forking can be achieved by using the Process Control Extensions. Getting a good grip on it, may take some studying though.

System_Daemon

Because the Process Control Extensions‘ documentation is a bit rough, I decided to figure it out once, and then wrap my knowledge and the required code inside a PEAR class called: System_Daemon. And so now you can just:

require_once “System/Daemon.php”;                 // Include the Class
 
System_Daemon::setOption(“appName”, “mydaemon”);  // Minimum configuration
System_Daemon::start();                           // Spawn Deamon!

And that’s all there is to it. The code after that, will run in your server’s background. So next, if you create a while(true) loop around that code, the code will run indefinitely. Remember to build in a sleep(5) to ease up on system resources.

Features & Characteristics

Here’s a grab of System_Daemon’s features:

Daemonize any PHP-CLI script
Simple syntax
Driver based Operating System detection
Unix only
Additional features for Debian / Ubuntu based systems like:
Automatically generate startup files (init.d)
Support for PEAR’s Log package
Can run with PEAR (more elegance & functionality) or without PEAR (for standalone packages)
Default signal handlers, but optionally reroute signals to your own handlers.
Set options like max RAM usage

Download

You could download the package from PEAR, or, if you have PEAR installed on your system: just run this from a console:

pear install -f System_Daemon

You can also update it using that last command.

Beta

Though I have quite some daemons set up this way, it’s officially still beta. So please report any bugs over at the PEAR page. Other comments may be posted here.

Complex Example

Ready to dig a little deeper? This example program is called ‘logparser’, it takes a look at a more complex use of System_Daemon. For instance, it introduces command line arguments like:

--no-daemon              # just run the program in the console this time
--write-initd            # writes a startup file

Read this source to get the picture. Don’t forget the comments!

#!/usr/bin/php -q

/**
 * System_Daemon turns PHP-CLI scripts into daemons.
 *
 * PHP version 5
 *
 * @category  System
 * @package   System_Daemon
 * @author    Kevin 
 * @copyright 2008 Kevin van Zonneveld
 * @license   http://www.opensource.org/licenses/bsd-license.php
 * @link      http://github.com/kvz/system_daemon
 */
 
/**
 * System_Daemon Example Code
 *
 * If you run this code successfully, a daemon will be spawned
 * but unless have already generated the init.d script, you have
 * no real way of killing it yet.
 *
 * In this case wait 3 runs, which is the maximum for this example.
 *
 *
 * In panic situations, you can always kill you daemon by typing
 *
 * killall -9 logparser.php
 * OR:
 * killall -9 php
 *
 */
 
// Allowed arguments & their defaults 
$runmode = array(
    ‘no-daemon’ => false,
    ‘help’ => false,
    ‘write-initd’ => false,
);
 
// Scan command line attributes for allowed arguments
foreach ($argv as $k=>$arg) {
    if (substr($arg, 0, 2) == ‘–’ && isset($runmode[substr($arg, 2)])) {
        $runmode[substr($arg, 2)] = true;
    }
}
 
// Help mode. Shows allowed argumentents and quit directly
if ($runmode['help'] == true) {
    echo ‘Usage: ‘.$argv[0].‘ [runmode]‘ . “\n“;
    echo ‘Available runmodes:’ . “\n“;
    foreach ($runmode as $runmod=>$val) {
        echo ‘ –’.$runmod . “\n“;
    }
    die();
}
 
// Make it possible to test in source directory
// This is for PEAR developers only
ini_set(‘include_path’, ini_get(‘include_path’).‘:..’);
 
// Include Class
error_reporting(E_ALL);
require_once ‘System/Daemon.php’;
 
// Setup
$options = array(
    ‘appName’ => ‘logparser’,
    ‘appDir’ => dirname(__FILE__),
    ‘appDescription’ => ‘Parses vsftpd logfiles and stores them in MySQL’,
    ‘authorName’ => ‘Kevin van Zonneveld’,
    ‘authorEmail’ => ‘kevin@vanzonneveld.net’,
    ’sysMaxExecutionTime’ => ‘0′,
    ’sysMaxInputTime’ => ‘0′,
    ’sysMemoryLimit’ => ‘1024M’,
    ‘appRunAsGID’ => 1000,
    ‘appRunAsUID’ => 1000,
);
 
System_Daemon::setOptions($options);
 
// This program can also be run in the forground with runmode –no-daemon
if (!$runmode['no-daemon']) {
    // Spawn Daemon 
    System_Daemon::start();
}
 
// With the runmode –write-initd, this program can automatically write a 
// system startup file called: ‘init.d’
// This will make sure your daemon will be started on reboot 
if (!$runmode['write-initd']) {
    System_Daemon::info(‘not writing an init.d script this time’);
} else {
    if (($initd_location = System_Daemon::writeAutoRun()) === false) {
        System_Daemon::notice(‘unable to write init.d script’);
    } else {
        System_Daemon::info(
            ’sucessfully written startup script: %s’,
            $initd_location
        );
    }
}
 
// Run your code
// Here comes your own actual code
 
// This variable gives your own code the ability to breakdown the daemon:
$runningOkay = true;
 
// This variable keeps track of how many ‘runs’ or ‘loops’ your daemon has
// done so far. For example purposes, we’re quitting on 3.
$cnt = 1;
 
// While checks on 3 things in this case:
// - That the Daemon Class hasn’t reported it’s dying
// - That your own code has been running Okay
// - That we’re not executing more than 3 runs 
while (!System_Daemon::isDying() && $runningOkay && $cnt <=3) {
    // What mode are we in?
    $mode = ‘”‘.(System_Daemon::isInBackground() ? ” : ‘non-’ ).
        ‘daemon” mode’;

    // Log something using the Daemon class’s logging facility
    // Depending on runmode it will either end up:
    //  - In the /var/log/logparser.log
    //  - On screen (in case we’re not a daemon yet)  
    System_Daemon::info(‘{appName} running in %s %s/3′,
        $mode,
        $cnt
    );

    // In the actuall logparser program, You could replace ‘true’
    // With e.g. a  parseLog(’vsftpd’) function, and have it return
    // either true on success, or false on failure.
    $runningOkay = true;
    //$runningOkay = parseLog(’vsftpd’);

    // Should your parseLog(’vsftpd’) return false, then
    // the daemon is automatically shut down.
    // An extra log entry would be nice, we’re using level 3,
    // which is critical.
    // Level 4 would be fatal and shuts down the daemon immediately,
    // which in this case is handled by the while condition.
    if (!$runningOkay) {
        System_Daemon::err(‘parseLog() produced an error, ‘.
            ’so this will be my last run’);
    }

    // Relax the system by sleeping for a little bit
    // iterate also clears statcache
    System_Daemon::iterate(2);

    $cnt++;
}
 
// Shut down the daemon nicely
// This is ignored if the class is actually running in the foreground
System_Daemon::stop();

Console action: Controlling the Daemon

Now that we’ve created an example daemon, it’s time to fire it up! I’m going to assume the name of your daemon is logparser. This can be changed with the statement: System_Daemon::setOption('appName', 'logparser'). But the name of the daemon is very important because it is also used in filenames (like the logfile).

Execute

Just make your daemon script executable, and then execute it:

chmod a+x ./logparser.php ./logparser.php

Check

Your daemon has no way of communicating through your console, so check for messages in:

tail /var/log/logparser.log And see if it’s still running:

ps uf -C logparser.php

Kill

Without the start/stop files (see below for howto), you need to:

killall -9 logparser.php Autch.. Let’s work on those start / stop files, right?

Start / Stop files (Debian & Ubuntu only)

Real daemons have an init.d file. Remember you can restart Apache with the following statement?

/etc/init.d/apache2 restart That’s a lot better than killing. So you should be able to control your own daemon like this as well:

/etc/init.d/logparser stop /etc/init.d/logparser start Well with System_Daemon you can write autostartup files using the writeAutoRun() method, look:

$path = System_Daemon::writeAutoRun();On success, this will return the path to the autostartup file: /etc/init.d/logparser, and you’re good to go!

Run on boot

Surely you want your daemon to run at system boot.. So on Debian & Ubuntu you could type:

update-rc.d logparser defaults Done your daemon now starts every time your server boots. Cancel it with:

update-rc.d -f logparser remove

Logrotate

Igor Feghali shares with us a logrotate config file to keep your log files from growing too large. Just place a file in your /etc/logrotate.d/.

/var/log/mydaemon.log { rotate 15 compress missingok notifempty sharedscripts size 5M create 644 mydaemon_user mydaemon_group postrotate /bin/kill -HUP `cat /var/run/mydaemon/mydaemond.pid 2>/dev/null` 2> /dev/null || true endscript } Obviously, replace the mydaemon occurances with values corresponding to your environment. Thanks Igor!

Troubleshooting

Here are some issues you may encounter down the road.

Don’t use echo() **Echo writes to the STDOUT of your current session. If you logout, that will cause fatal errors and the daemon to die. Use System_Daemon::log() instead.
Connect to MySQL after you start() the daemon. Otherwise only the parent process will have a MySQL connection, and since that dies.. It’s lost and you will get a ‘MySQL has gone away’ error.
Error handling Good error handling is imperative. Daemons are often mission critical applications and you don’t want an uncatched error to bring it to it’s knees.
- Reconnect to MySQL A connection may be interrupted. Think about network downtime or lock-ups when your database server makes backups. Whatever the cause: You don’t want your daemon to die for this, let it try again later.
- PHP error handler As of 0.6.3, System_Daemon forwards all PHP errors to the log() method, so keep an eye on your logfile. This behavior can be controlled using the logPhpErrors (true||false) option.
Monit Monit is a standalone program that can kickstart any daemon, based on your parameters. Should your daemon fail, monit will mail you and try to restart it.
Watch that memory Some classes keep a history of executed commands, sent mails, queries, whatever. They were designed without knowing they would ever be used in a daemonized environment. Cause daemons run indefinitely this ‘history’ will expand indefinitely. Since unfortunately your server’s RAM is not infinite, you will run into problems at some point. This makes it’s very important to address these memory ‘leaks’ when building daemons.
Statcache will corrupt your data If you do a file_exists(), PHP remembers the results to ease on your disk until the process end. That’s ok but since the Daemon process does not end, PHP will not be able to give you up to date information. As of 0.8.0 you should call System_Daemon::iterate(2) instead of e.g. sleep(2), this will sleep & clear the cache and give you fresh & valid data.

I know I’m saying MySQL a lot, but you can obviously replace that with Oracle, MSSQL, PostgreSQL, etc.

run php script on startup

admin — Sun, 07 Feb 2010 11:04:48 +0000

Suse appears to use init scripts to launch apps at start up and you will need to write a custom init script to launch your socket.php script.

At the bare minimum, you could create an executable script in /etc/rc2.d named S99socket containing
#!/bin/sh /path/to/php /path/to/socket.php &

Installing !Openmeetings on debian etch

admin — Sun, 31 Jan 2010 07:00:04 +0000

First variant (works with lenny as well):

Download the following debian package: http://www.expressaas.com/distrib/release/red5-openmeetings_1.0.2760.noarch.deb

And install it using sudo dpkg -i red5-openmeetings_1.0.2760.noarch.deb command. All additional utilities, such as Openoffice, Ghostscript, Imagemagick and Swftools should be installed as described below.

Second variant (outdated):

this sample is rather outdated

the installation procedure (if you forget of all 3th party requirements) is as simple as the following:

donwload openmeetings-package (you can download it into your home-directory)
unzip it
cd /openmeetings-package/webapps/openmeetings/conf and configure the hibernate.cfg.xml
cd up again to /openmeetings-package/ run the red5.sh

that is all!

no copy of any dirs, no /etc/init.d/, ^^ In doubt see what is written down in here:http://code.google.com/p/openmeetings/wiki/InstallationOpenMeetings There is no mention of any init.d-script or other copy actions.

In this how-to I’m going to descript way to install OpenMeetings on debian GNU/Linux Etch (4.0), Steps are following way:

What we need!
Install MySQL
Install xvfb and OpenOffice.org
Install ImageMagic & !Ghostscript
Install SwfTools
Install Java and red5
Download openlazslo
Install OpenMeetings
Installing must new version?
Configure OpenMeetings and place files
Start every thing
!Troobleshooting
Author

What We Need

In this article I will use aptitude to install packages, if you don’t have apptitude please install it before going forward :

$su
#apt-get update
#apt-get install aptitude

After aptitude we need Debian GNU/Linux, I use version 4.0 (code name Etch), befor installing any thing else I recommend you to create a directory and manage every thing from there:

#su
#mkdir /root/tmpOpenMeetings/
#cd  /root/tmpOpenMeetings/

Install !MySQL

OpenMeetings can work with wide range of databases, I will install OpenMeetings with MySQL, to install !MySQL server:

aptitude install mysql-server

Add/edit the following lines to /etc/mysql/my.conf to enable localization:

[mysqld]
default-character-set=utf8
character-set-server=utf8

Install xvfb and OpenOffice

If you would like exchange Presentation and Office documentation in OpenMeetings, you will nedd xvfb and OpenOffice.org

#aptitude install xvfb  openoffice.org

Then edit Setup.xcu:

#vim  /usr/lib/openoffice/share/registry/data/org/openoffice/Setup.xcu

You should insert following lines after: :

     oor:name=“ooSetupConnectionURL” oor:type=“xs:string”>
        socket,host=localhost,port=8100;urp

Install ImageMagick and Ghostscript

ImageMagick is a software suite for image manipulation and display, supporting close to 100 image formats. It is mainly used to perform various transformation and conversion operations on images and Ghostscript is a suite of software based on an interpreter for Adobe Systems’ PostScript and Portable Document Format (PDF) page description languages.

To install this tools run:

 #aptitude install imagemagick  gs-gpl

Install SWFTools

SWFTools s a collection of SWF manipulation and creation utilities written by Rainer Böhme and Matthias Kramm. It is released under the GPL.

#aptitude install swftools

If you get this message: “Couldn’t find any package whose name or description matched “swftools” ” please download swftools directly from web with running:

#wget   http://ftp.it.debian.org/debian/pool/main/s/swftools/swftools_0.8.1-1_i386.deb

befor installing this ackage should install “libart-2.0-2 ” so run:

#aptitude install libart-2.0-2

and now install SWFTools:

#dpkg -i swftools_0.8.1-1_i386.deb

Install Java and Red5

red5 is a Open Source Flash Server that OpenMeetings based on, so you should install it, and befor installing red5 should install Java Runtime Environment and Java development Kit run:

#aptitude install sun-java5-bin
#aptitude install  sun-java5-demo
#

If aptitude gives you any error, please download all file with wget and then install

#wget http://ftp.tr.debian.org/debian/pool/non-free/s/sun-java5/sun-java5-demo_1.5.0-13-1_i386.deb
#wget http://ftp.de.debian.org/debian/pool/non-free/s/sun-java5/sun-java5-jdk_1.5.0-14-1etch1_i386.deb
# wget http://ftp.de.debian.org/debian/pool/non-free/s/sun-java5/sun-java5-bin_1.5.0-15-1_i386.deb
#dpkg -i sun-java5-demo_1.5.0-13-1_i386.deb sun-java5-jdk_1.5.0-14-1etch1_i386.deb sun-java5-bin_1.5.0-15-1_i386.deb

Now download red5 for Debian GNU/Linux and install it:

#wget http://dl.fancycode.com/red5/0.6.3/debian/red5_0.6.3-1_all.deb
#dpkg -i red5_0.6.3-1_all.deb

openlazslo

OpenLaszlo is an open source platform for the development and delivery of rich Internet applications. to installing it, run:

#wget http://download.openlaszlo.org/4.0.6/openlaszlo-4.0.6-unix.tar.gz
#tar -xvf openlaszlo-4.0.6-unix.tar.gz
#mv lps-4.0.6/ /opt/

Note: there is no need to install OpenLaszlo if you only use the application but don’t want to modify it.

Note: you might would like to have a look at this shell script to start/stop/restart/status, if yes you can use this how-to.

Installing OpenMeetings

Huraaa, making infrastructure is finished, now we are going to download latest OpenMeeting release and instaling it:

#wget http://openmeetings.googlecode.com/files/openmeetings051.zip
#unzip openmeetings051.zip

To installing OpenMeetings you should tell OM where is your DataBase server and as I use MySQL as my Server, steps are like this:

#cp openmeetings/conf/mysql_hibernate.cfg.xml openmeetings/conf/hibernate.cfg.xml

Now edit file and config your database:

#vim openmeetings/conf/hibernate.cfg.xml

Now change :

             name=“connection.username”>
             name=“connection.password”>
             name=“connection.url”>jdbc:mysql:///

For example my config look likes:

 
                 name=“connection.username”>root
                 name=“connection.password”>dj76shwrsh16xsvak1

                
                 name=“connection.driver_class”>com.mysql.jdbc.Driver
                 name=“dialect”>org.hibernate.dialect.MySQLInnoDBDialect
                 name=“connection.url”>jdbc:mysql://localhost/openmeetings?useUnicode=true&createDatabaseIfNotExist=true&characterEncoding=utf-8

Installing Must new Version?

If you would like get must new version, I mean the version is under development, you should get a Snapshot from current source code, to do this follow this steps, if you don’t like to have any thing more than OpenMeetings latest version or don’t know what’s snapshot, skip this step.

nstall Subversion if you don’t have:

#aptitude install subversion

Get (checkout) OpenMeetings latest snapshot:

#svn checkout http://openmeetings.googlecode.com/svn/branches/dev/

I will rename dev to !OpenMeetingsFromSVN and then replace what updated in snapshot (from subversion) with what should be out of date in orginal openmeetings file downloaded from OpenMeetings and OpnLazslo:

# mv dev/ OpenMeetingsFromSVN
#cp -r OpenMeetingsFromSVN/laszlo/client/xmlcrm/videoconference/ /opt/lps-4.0.6/Server/lps-4.0.6/

Configure OpenMeetings

Now, first I update my language files:

#cp OpenMeetingsFromSVN/xmlcrm/java/webapp/openmeetings/languages/*  openmeetings/languages/.

Ok, It’s time to place my OpenMeting in red5 document root to serving:

#cp -r openmeetings/ /usr/lib/red5/webapps/

Start every thing

Now time to start every thing we installed, I will start OpenOffice.org at first and then OpenLazslo and will start red5 server:

#xvfb-run –server-args=’-screen 0 800×600x16′ -a /usr/lib/openoffice/program/soffice -headless -nologo -norestore & 
#export JAVA_HOME=/usr/lib/jvm/java-1.5.0-sun
#/opt/lps-4.0.6/Server/tomcat-5.0.24/bin/startup.sh
#/etc/init.d/red5 start

Instead of using a virtual frame buffer you may install and use a /etc/init.d/ooomeetings service.

The last part of instalation is web based, with your web browser (Firefox, Opera, IE, …) and servers IP address and port 5080 (default):

http://$YOUR_IP:5080/openmeetings/Install

For example: http://127.0.0.1:5080/openmeetings/Install

after putting information in forms, OpenMeetings will initialize a DataBase (based on information that we gived to him) and now you can access OpenMeetings first page at:

http://$YOUR_IP:8080/lps-4.0.6/videoconference/

For example: http://127.0.0.1:5080/openmeetings/

Congratulation, OpenMeetings is ready to use

Touble Shooting

If you get any message about locales or fonts, you can use :

#dpkg-reconfigure locales
#aptitude install xfonts-base

If you would like to change rtmp host, you can use:

vim  /opt/lps-4.0.6/Server/lps-4.0.6/videoconference/config.xml

PG Map

admin — Fri, 06 Nov 2009 10:52:31 +0000

Netcall Setup

admin — Fri, 06 Nov 2009 10:32:43 +0000

TOT Netcall for Nokia Phone

การใช้ Google Map Api หาเส้นทาง จากจุดสองจุด

admin — Thu, 15 Oct 2009 03:53:17 +0000


setAPIKey('ABQIAAAAPOHd09dXhJtbKHeZpxlh6BTdM_BGb_HRDyhTa-dAuFdRUQ382BTsqAFfGu_x3jaT_hgEvzyEiREMIg');
$map->setMapType('map');
$map->enableInfoWindow();
$map->enableDirections();
$map->setInfoWindowTrigger('mouseover');
$map->setWidth('400px');
$map->setHeight('400px');
$map->setFT('13.786987220018625,100.60581922531128','13.780276823001238,100.60309410095215');

?>

    
    
    printHeaderJS(); ?>
    printMapJS(); ?>
    
    
    
    
    
    
    printMap(); ?>

    
	
    printSidebar(); ?>

MySql Trigger - Basic

admin — Thu, 15 Oct 2009 03:38:55 +0000

Trigger คือการแทรกการกระทำ (Method/Function) ลงไว้ใน Database โดยสามารถใส่เงื่อนไขต่างๆได้เหมือนกับภาษาโปรแกรมทั่วไปครับ โดยเมื่อเกิด Query ใน Mysql แล้วตัว Database จะทำการไล่ Check ว่ามี Trigger ไหนตรงตามเงื่อนไขบ้าง และเรียกใช้งาน

การใช้ Trigger เป็นเหมือนดาบสองคม มีทั้งข้อดีแล้วข้อเสียครับ จะแจกแจงคร่าวๆเท่าที่พอนึกออกไว้ให้ครับ

+ ดูดีมีชาติตระกูล เร็ว (เร็วกว่าที่ส่งข้อมูลไปๆมาๆระหว่าง Mysql กับ Php/Server-side script อื่นๆ)

+ ทำบางอย่างที่ทำด้วยโค้ด Server-side script มาตราฐานไม่ได้ หรือไม่สะดวกนัก โดยการ Hook เข้าไปในระบบของ DB เลย

- Debug ยาก ยิ่งมีภาษาเพิ่มเข้ามาอีก ยิ่งเพิ่มความปวดหัว

- ยึดติดกับ Platform เนื่องจาก Trigger ไม่มีมาตราฐานชัดเจน ทำให้เมื่อย้ายไปใช้ตัวอื่นจะต้องศึกษาใหม่

Replacement

จริงๆ ในหลายๆกรณีก็ไม่จำเป็นต้องใช้ Trigger เช่นการ Update Table ที่เป็น Foreign key โดยสามารถใช้คำสั่ง Cascade ช่วยได้

http://dev.mysql.com/doc/refman/5.1/en/innodb-foreign-key-constraints.html

Mysql Trigger พื้นฐาน

หน้าตาตัวอย่าง TriggerCREATE TRIGGER trigger_name BEFORE UPDATE ON table_name FOR EACH ROW BEGIN IF NEW.dirty=0 OR NEW.dirty=1 THEN SET NEW.dirty=1; ELSE SET NEW.dirty=0; END IF; END;

CREATE TRIGGER trigger_name คำสั่งสร้าง Trigger
BEFORE UPDATE Event หลักๆที่เราสามารถ Hook trigger ของเราเข้าไปได้ ได้แก่ INSERT, UPDATE, DELETE โดยสามารถเลือกว่าจะทำการ Hook ก่อนหรือหลัง (BEFORE / AFTER) Query เหล่านั้นได้
ON table_name เลือก Table ที่ต้องการให้ Trigger ทำงาน
หมายถึงข้อมูลเก่าก่อนที่จะเกิดการรัน Query นั้นๆ
นอกจากนี้ยังสามารถแทรก Query มาตราฐาน (INSERT,UPDATE,DELETE และอื่นๆ) ลงใน Trigger ได้เลยอีกด้วย ซึ่งเราสามารถนำตัวแปร ROW,OLD,NEW มาใช้งานได้เช่นกัน

สร้าง Trigger บน phpMyAdmin

ถ้าได้ลองเอาโค้ดตัวอย่างไปลอง Run ใน phpMyAdmin จะพบว่าไม่สามารถทำงานได้ ด้วย Error ที่อ่านไม่ค่อยจะเข้าใจนัก

เหตุผลphpMyAdmin ไม่สามารถ Run คำสั่งนี้ได้ เนื่องจากเกิดการสับสนเรื่อง Delimiter ของ Mysql กับ คำสั่งใน Trigger

วิธีการแก้ไข แก้ได้ด้วยการ เปลี่ยน Delimiter เป็นตัวอักษรอื่นแทน semicolon “;” ตามรูป

ในตัวอย่างเปลี่ยนเป็น ;; แทนครับ โดยถ้าหากเราต้องการสั่งให้ phpMyAdmin ทำงานหลายๆ Query พร้อมกันก็ให้ใส่ ;; แทน ;

credit:http://blog.levelup.in.th/2009/06/29/mysql-trigger-basicmysql-trigger-basic/

ติดตั้ง Vdo Web conference

admin — Thu, 08 Oct 2009 10:37:45 +0000

InstallingBigBlueButton

How to install BigBlueButton like a real developer.

These instructions will walk through how to install BigBlueButton from source onto Ubuntu. If you are using CentOS, seeInstallingBigBlueButtonCentOS. In most cases, you’ll want to install from packages, but if you want to really understand how BigBlueButton is setup, the following steps will show you how to install each component.

To start, you’ll need a computer running Ubuntu — either a physical machine or a virtual machine (VM). The easiest way to start with a VM images is to download a Ubuntu VM image from http://www.vmware.com/appliances/directory/va/147323/download and start it in VMWare Player

The only prerequisite is that your Ubuntu machine has a network connection.

To start, check if you have a network connection

 > ping www.google.com

If you get an error saying yout eth0 is not connected, then fix it by:

  Check if it is using eth1 

root@ubuntu904server:/usr/local# ifconfig -a
eth1      Link encap:Ethernet  HWaddr 00:0c:29:dd:b4:51
          inet addr:192.168.0.154  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fedd:b451/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:4080349 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3932137 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1216680270 (1.2 GB)  TX bytes:822963271 (822.9 MB)
          Interrupt:19 Base address:0×2000

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:12938 errors:0 dropped:0 overruns:0 frame:0
          TX packets:12938 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:40299608 (40.2 MB)  TX bytes:40299608 (40.2 MB)

root@ubuntu904server:/usr/local# vi /etc/udev/rules.d/70-persistent-net.rules
Swap the two entries by eidting “NAME=eth1″ to “NAME=eth0″ and vice versa.

Reboot your machine.

Check if you manage to connect to the internet.

If you are running on a Virtual Machine, make sure the VM’s network adapter is using a Bridged connection instead of NAT.

On the VMWare player this is enabled in the Devices menu at the top.

More info can be found here http://ubuntuforums.org/showthread.php?t=221768

Once you have interner connection, update and upgrade.

  > sudo apt-get update
  > sudo apt-get upgrade

Install Java 6

 > apt-get install openjdk-6-jre-headless

Install MySQL

 > apt-get install mysql-server

Install Tomcat

  > apt-cache search tomcat

  > apt-get install tomcat6

Confirm that tomcat is running

  http://:8080/

Install swftools

  > apt-get install swftools

Install ImageMagick

  > apt-get install imagemagick

Install Nginx

  > apt-get install nginx

Install ActiveMQ

  > cd opt
  > wget http://apache.mirror.rafal.ca/activemq/apache-activemq/5.2.0/apache-activemq-5.2.0-bin.tar.gz
  > tar zxvf apache-activemq-5.2.0-bin.tar.gz

  Start ActiveMQ
  > /opt/apache-activemq-5.2.0/bin/activemq

Modify tomcat6 account

 > vi /etc/passwd

 Modify tomcat6 entry to this
  tomcat6:x:106:113::/usr/share/tomcat6:/bin/bash

Install red5

  > cd opt
  > wget http://build.xuggle.com/job/red5_jdk6_stable/131/artifact/workingcopy/red5-0.8.RC3-build-hudson-red5_jdk6_stable-131.tar.gz
  > tar zxvf red5-0.8.RC3-build-hudson-red5_jdk6_stable-131.tar.gz
  > mv red5-0.8.RC3-build-hudson-red5_jdk6_stable-131 red5-0.8

  Start red5 as tomcat6 user
  > sudo su -l tomcat6
  > red5.sh

Install oflaDemo

http://192.168.0.154:5080/

Click on “Click here to install demos” and then choose oflaDemo java 6.

http://192.168.0.154:5080/demos/

http://192.168.0.154:5080/demos/ofla_demo.html

Edit rtmp://192.168.0.154/oflaDemo and click connect

You would see a list of available videos. Select one to play.

Prepare to install Asterisk

Some info found here http://godson.in/how-to-install-asterisk-on-ubuntu

 > apt-get install build-essential
 > apt-get install linux-headers-`uname -r`
 > apt-get install libssl-dev
 > apt-get install ncurses-dev
 > apt-get install libnewt-dev
 > apt-get install zlib1g-dev
 > apt-get install bison

Install Dahdi

You may have to find out what the newest version is. Go here

 > cd /usr/local/src
 > wget http://downloads.asterisk.org/pub/telephony/dahdi-linux-complete/dahdi-linux-complete-2.2.0.2+2.2.0.tar.gz
 > tar zxvf dahdi-linux-complete-2.2.0.1+2.2.0.tar.gz
 > cd dahdi-linux-complete-2.2.0.1+2.2.0
 > make all
 > make install
 > make config

Install Asterisk

  > cd /usr/local/src
  > wget http://downloads.asterisk.org/pub/telephony/asterisk/releases/asterisk-1.4.25.tar.gz
  > tar zxvf asterisk-1.4.25.tar.gz
  > cd asterisk-1.4.25
  > more README
  > ./configure
  > make
  > make install
  > make samples
  > make config

Modify Extensions

cd /tmp/
wget http://bigbluebutton.googlecode.com/files/asterisk-extensions.conf
cat asterisk-extensions.conf >> /etc/asterisk/extensions.conf

Create SIP account

wget http://bigbluebutton.googlecode.com/files/asterisk-sip.conf
cat asterisk-sip.conf >> /etc/asterisk/sip.conf

Create SIP Accounts to be used by Red5Phone

wget http://bigbluebutton.googlecode.com/files/asterisk-create-sip-accounts.sh
chmod a+x asterisk-create-sip-accounts.sh
./asterisk-create-sip-accounts.sh

Test your SIP account

 Download Zoiper from here http://www.zoiper.com/zwin.php

 After installing Zoiper, start it and create a SIP account using the echotest user above.

 Then dial 600. You should be connected to the “Echo” application.

Create AMI account

 > vi /etc/asterisk/manager.conf

 Modify “enabled” to yes

[general]

enabled = yes

  Add the following at the bottom of the file

; BigBlueButton: Enable Red5 to connect
[bbb]
secret = secret
permit = 0.0.0.0/0.0.0.0
read = system,call,log,verbose,command,agent,user
write = system,call,log,verbose,command,agent,user

Configure Nginx

 > vi /etc/nginx/sites-available/bigbluebutton

 Paste the following into the file and edit server_name with you IP.

server {
     listen   80;
     server_name  192.168.0.136;

     access_log  /var/log/nginx/bigbluebutton.access.log;

      location ~ (/open/|/close/|/idle/|/send/) {
          proxy_pass         http://127.0.0.1:8088;
          proxy_redirect     off;
          proxy_set_header   X-Forwarded-For   $proxy_add_x_forwarded_for;

          client_max_body_size       10m;
          client_body_buffer_size    128k;

          proxy_connect_timeout      90;
          proxy_send_timeout         90;
          proxy_read_timeout         90;

          proxy_buffering            off;
      }

       location /deskshare {
           proxy_pass         http://127.0.0.1:5080;
           proxy_redirect     default;
           proxy_set_header   X-Forwarded-For   $proxy_add_x_forwarded_for;
           client_max_body_size       10m;
           client_body_buffer_size    128k;
           proxy_connect_timeout      90;
           proxy_send_timeout         90;
           proxy_read_timeout         90;
           proxy_buffer_size          4k;
           proxy_buffers              4 32k;
           proxy_busy_buffers_size    64k;
           proxy_temp_file_write_size 64k;
           include    fastcgi_params;
       }

       location /bigbluebutton {
           proxy_pass         http://127.0.0.1:8080;
           proxy_redirect     default;
           proxy_set_header   X-Forwarded-For   $proxy_add_x_forwarded_for;

           client_max_body_size       10m;
           client_body_buffer_size    128k;

           proxy_connect_timeout      90;
           proxy_send_timeout         90;
           proxy_read_timeout         90;

           proxy_buffer_size          4k;
           proxy_buffers              4 32k;
           proxy_busy_buffers_size    64k;
           proxy_temp_file_write_size 64k;

           include    fastcgi_params;
       }

        location / {
          root   /var/www/bigbluebutton-default;
          index  index.html index.htm;
        }

        location /client {
                root    /var/www/bigbluebutton;
                index  index.html index.htm;
        }

        #error_page  404  /404.html;

        # redirect server error pages to the static page /50x.html
        #
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
                root   /var/www/nginx-default;
        }
}

Enable the bigbluebutton nginx config

> ln -s /etc/nginx/sites-available/bigbluebutton /etc/nginx/sites-enabled/bigbluebutton

Download BigBlueButton

 > mkdir /home/user/temp
 > cd /home/user/temp
 > wget http://www.bigbluebutton.org/hudson/job/BBB-Trunk-Apps/ws/dist/bigbluebutton-apps-0.5.tar.gz
 > wget http://www.bigbluebutton.org/hudson/job/BBB-Trunk-Apps-Deskshare/ws/dist/webapps/deskshare.tar.gz
 > wget http://www.bigbluebutton.org/hudson/job/BBB-Trunk-Client/ws/client.tar.gz
 > wget http://www.bigbluebutton.org/hudson/job/BBB-Trunk-Web/ws/bigbluebutton-0.1.war
 > wget http://www.bigbluebutton.org/hudson/job/BBB-Trunk-Config/ws/web//*zip*/web.zip
 > wget http://www.bigbluebutton.org/hudson/job/bbb-trunk-apps-sip/ws/dist/webapps/sip.tar.gz
 > wget http://www.bigbluebutton.org/hudson/job/bbb-trunk-apps-video/ws/dist/webapps/video.tar.gz

Disable Security settings for TOMCAT6

  > vi /etc/default/tomcat6

  Edit and uncomment #TOMCAT6_SECURITY=yes to

  TOMCAT6_SECURITY=no

setup the database

 > mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 33
Server version: 5.0.75-0ubuntu10.2 (Ubuntu)

Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the buffer.

mysql> create database bigbluebutton_dev;
Query OK, 1 row affected (0.05 sec)

mysql> grant all on bigbluebutton_dev.* to ‘bbb’@‘localhost’ identified by ’secret’;
Query OK, 0 rows affected (0.04 sec)

mysql> commit;
Query OK, 0 rows affected (0.00 sec)

mysql>

Install BigBlueButton Web

 > cd /var/lib/tomcat6/webapps
 > cp /home/user/temp/bigbluebutton-0.1.war ./bigbluebutton.war

Determine PDF2SWF, CONVERT and GS applications

  Make a note of where pdf2swf is installed
  > which pdf2swf

  You should see something like
  /usr/bin/pdf2swf

  Make a note of where the convert application is installed
  > which convert

  You shoud see something like.
  /usr/bin/convert

  Note where GhostScript is installed
  > which gs

  You shoud see something like.
  /usr/bin/gs

Edit bbb-web properties

 > vi /var/lib/tomcat6/webapps/bigbluebutton/WEB-INF/classes/bigbluebutton.properties

Change the following:
 - swfToolsDir to the directory where pdf2swf is located
 - imageMagickDir to the directory where convert is located
 - ghostScriptExec to point to the gs application
 - change bigbluebutton.web.serverURL=http://

Your bigbluebutton.properties should resemble something like this

#
# These are the default properites for BigBlueButton Web application

dataSource.url=jdbc:mysql://localhost/bigbluebutton_dev
dataSource.username=bbb
dataSource.password=secret

swfToolsDir=/usr/bin
imageMagickDir=/usr/bin
presentationDir=/var/bigbluebutton
ghostScriptExec=/usr/bin/gs

beans.presentationService.swfToolsDir=${swfToolsDir}
beans.presentationService.imageMagickDir=${imageMagickDir}
beans.presentationService.presentationDir=${presentationDir}

# Use fullpath to ghostscript executable since the exec names are different
# for each platform.
beans.presentationService.ghostScriptExec=${ghostScriptExec}

#
# This URL needs to reference the host running the tomcat server
bigbluebutton.web.serverURL=http://192.168.0.154

# This is a workaround for a problem converting PDF files, referenced at
# http://groups.google.com/group/comp.lang.postscript/browse_thread/thread/c2e264ca76534ce0?pli=1
noPdfMarkWorkaround=/etc/bigbluebutton/nopdfmark.ps
beans.presentationService.noPdfMarkWorkaround=${noPdfMarkWorkaround}

Restart Tomcat6

 > /etc/init.d/tomcat6 restart

Check if database tables were created

 > mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 56
Server version: 5.0.75-0ubuntu10.2 (Ubuntu)

Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the buffer.

mysql> use bigbluebutton_dev;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
+—————————–+
| Tables_in_bigbluebutton_dev |
+—————————–+
| account                     |
| account_conference          |
| account_user                |
| conference                  |
| permission                  |
| role                        |
| role_permission_rel         |
| scheduled_session           |
| user                        |
| user_permission_rel         |
| user_role_rel               |
| voice_conference_bridge     |
+—————————–+
12 rows in set (0.00 sec)

mysql> select * from user;
+—-+———+———————+———–+———————+——————————————+—————-+
| id | version | date_created        | full_name | last_updated        | password_hash                            | username       |
+—-+———+———————+———–+———————+——————————————+—————-+
|  1 |       0 | 2009-06-29 09:51:17 | Admin     | 2009-06-29 09:51:17 | d033e22ae348aeb5660fc2140aec35850c4da997 | admin@test.com |
+—-+———+———————+———–+———————+——————————————+—————-+
1 row in set (0.02 sec)

mysql>

Create the Presentation Upload directory

 > mkdir /var/bigbluebutton
 > chown -R tomcat6:adm /var/bigbluebutton
 > chmod -R 777 /var/bigbluebutton

Install bbb-apps

 > cd /opt/red5-0.8/webapps
 > cp /home/user/temp/bigbluebutton-apps-0.5.tar.gz ./

 > tar zxvf bigbluebutton-apps-0.5.tar.gz
 >  mv webapps/bigbluebutton ./
 > rm -rf bigbluebutton-apps-0.5.tar.gz webapps/

Edit BigBlueButton Apps properties

 > vi /opt/red5-0.8/webapps/bigbluebutton/WEB-INF/bigbluebutton.properties

# Location for recordings
recordingsDirectory=/var/bigbluebutton

# These properties are for Asterisk Management Interface (AMI)
ami.host=127.0.0.1
ami.port=5038
ami.username=bbb
ami.password=secret

Uncommet RTMPT section of /opt/red5-0.8/conf/red5-core.xml

Install Xuggler

 Goto http://www.xuggle.com/xuggler/downloads/

  > cd /usr/local
  >  wget http://com.xuggle.s3.amazonaws.com/xuggler/xuggler-3.1.FINAL/xuggle-xuggler.3.1.818-i686-pc-linux-gnu.sh

  > chmod a+x xuggle-xuggler.3.1.818-i686-pc-linux-gnu.sh
  > ./xuggle-xuggler.3.1.818-i686-pc-linux-gnu.sh

Put Xuggler into PATH

  >  vi /etc/profile

 Add the following at the bottom of the file

export XUGGLE_HOME=/usr/local/xuggler
export LD_LIBRARY_PATH=$XUGGLE_HOME/lib:$LD_LIBRARY_PATH
export PATH=$XUGGLE_HOME/bin:$PATH

Install Desk Share App

 > cd /opt/red5-0.8/webapps
 > cp /home/user/temp/deskshare.tar.gz ./
 > tar zxvf deskshare.tar.gz
 >  rm deskshare.tar.gz

Install Video App

 > cd /opt/red5-0.8/webapps
 > cp /home/user/temp/video.tar.gz ./
 > tar zxvf video.tar.gz
 >  rm video.tar.gz

Install Voice App

 > cd /opt/red5-0.8/webapps
 > cp /home/user/temp/sip.tar.gz ./
 > tar zxvf sip.tar.gz
 >  rm sip.tar.gz

 Edit /opt/red5-0.8/webapps/sip/WEB-INF/bigbluebutton-sip.properties

 Point sip.server.host to the IP of your Asterisk installation

 sip.server.host=192.168.0.177

Install BigBlueButton Client

  > cd /var/www
  > mkdir bigbluebutton
  > cd bigbluebutton
  > cp /home/user/temp/client.tar.gz ./
  > tar zxvf client.tar.gz
  > rm client.tar.gz

Modify BBB client config in /var/www/bigbluebutton/client/conf/config.xml

 - Change the uri to your IP address
 - Change host=“conf/join-mock.xml” to host=“http:///bigbluebutton/conference-session/enter”

xml version=“1.0″ ?>
<config>
    <version>0.4</version>
    >
        <modules>

                <module name=“VideoModule” url=“VideoModule.swf”
                        uri=“rtmp://192.168.0.136/video”
                        onUserJoinedEvent=“START”
                        onUserLogoutEvent=“STOP”
                />
                <module name=“ChatModule” url=“ChatModule.swf”
                        uri=“rtmp://192.168.0.136/bigbluebutton”
                        loadNextModule=“PresentationModule”
                        onUserJoinedEvent=“START”
                        onUserLogoutEvent=“STOP”
                />
                <module name=“ViewersModule” url=“ViewersModule.swf”
                        uri=“rtmp://192.168.0.136/bigbluebutton”
                        host=“conf/join-mock.xml”
                        onAppInitEvent=“LOAD” loadNextModule=“ChatModule”
                        onAppStartEvent=“START”
                        onUserLogoutEvent=“STOP”
                />
                <module name=“ListenersModule” url=“ListenersModule.swf”
                        uri=“rtmp://192.168.0.136/bigbluebutton”
                        recordingHost=“http://192.168.0.136″
                        loadNextModule=“DeskShareModule”
                        onUserJoinedEvent=“START”
                        onUserLogoutEvent=“STOP”
                />
                <module name=“PresentationModule” url=“PresentationModule.swf”
                        uri=“rtmp://192.168.0.136/bigbluebutton”
                        host=“http://192.168.0.136″
                        loadNextModule=“ListenersModule”
                        onUserJoinedEvent=“START”
                        onUserLogoutEvent=“STOP”
                />

                <module name=“DeskShareModule” url=“DeskShareModule.swf”
                        uri=“rtmp://192.168.0.136/deskShare”
                        onUserJoinedEvent=“START”
                        onUserLogoutEvent=“STOP”
                        loadNextModule=“PhoneModule”
                />

                <module name=“PhoneModule” url=“PhoneModule.swf”
                        uri=“rtmp://192.168.0.136/sip”
                        onUserJoinedEvent=“START”
                        onUserLogoutEvent=“STOP”
                        loadNextModule=“VideoModule”
                />
        </modules>
config>

Install bbb-default pages

  > cd /var/www/
  > cp /home/user/temp/web.zip ./
  > apt-get install unzip
  > unzip -dc web.zip
  > mv c/web ./bigbluebutton-default
  > rm -rf c

Restart server apps

 * Start ActiveMQ
 * Start Red5 as tomcat6 user
 * Restart Tomcat
 * Restart Asterisk

Try out BigBlueButton

 Go to http:// which should display the bbb web page.

 To use voice conference, using your zoiper, dial 1500 which will prompt you for the conference number.

BigBlueButton-dev letting everyone know that you are a real developer and you have installed BigBlueButton from source.

MRTG on Ubuntu Server

admin — Fri, 11 Sep 2009 10:28:03 +0000

Lets start by installing the goods. Then we will get into the meat of things.

apt-get install snmpd mrtg apache2

When installing MRTG it will ask if you want to only make /etc/mrtg.cfg readable by the MRTG user. In my case, this will be an internal server only, and I do not need to worry about security, so I am going to select NO. If you choose YES, the steps in this tutorial may not work. I have not tested this. However, keep in mind if security is a concern, you may want to go this route and keep MRTG contained in a non-root user environment.

Assuming that you want to monitor your networking equipment with MRTG, you need to set up the snmp community on the piece of equipment. Usually its just a matter of enabling snmp, and the default community will be public. If you change the default community to another name, make sure you remember the name for later.

Now lets set up MRTG to read the data.
With Ubuntu server, MRTG will automatically set up /var/www/mrtg. In other distrobutions, it will set it up in a different area, so you will need to change the ‘WorkDir:’ variable in the following scenario to the directory where MRTG is installed.

I’m going to create an /etc/mrtg directory rather then move the mrtg.cfg file within /etc/ This will make it less confusing in the future.

mkdir /etc/mrtg

mv /etc/mrtg.cfg /etc/mrtg/

Now we run the cfgmaker command to get things up and running:

cfgmaker –global ‘WorkDir:/var/www/mrtg’ –global ‘Options[_]: bits,growright’ –output /etc/mrtg/mrtg.cfg public@

We need to make sure the following lines are correct in /etc/mrtg/mrtg.cfg If they are not there, add them.

EnableIPv6: no
RunAsDaemon: Yes
Interval: 5
Logdir: /var/log/mrtg

Now run:

indexmaker –output=/var/www/mrtg/index.html /etc/mrtg/mrtg.cfg

Which will build the index so you can view the output.

Then I run this command to set an environmental variable

env LANG=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg

and open http://localhost/mrtg/index.html

You should now see an output graph.

crontab -e
0,5,10,15,20,25,30,35,40,45,50,55 * * * * env LANG=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg –logging /var/log/mrtg.log

Let cron pick up stats for an hour or so. After a while, you will see that your graphs are picking up data about your bandwidth.

Here is mine with several cisco 2811 routers configured to show bandwidth.

SNMP and MRTG can monitor much more then bandwidth. For instance you can monitor disk usage, processing use, and more on your servers. There is plenty of documenation on the subject, which leans towards going in and adding snmpd to the servers you want to monitor, setting it up, and then going back and executing the cfgmaker and indexmaker command again so that the new hardware will show up on the page. Because the output of these files is an html page, you can also skin the page and make it look nicer, or embed it into your favorite CMS.

I encourage you to play around with MRTG, because it is the foundation program for a lot of software suites that monitor traffic. One of those, we will talk about next time. Until then, keep hackin.