Monitoring services using Mon

mon is a general-purpose scheduler and alert management tool used for monitoring service availability and
triggering alerts upon failure detection.

Mon uses some Linux command and services such as ping command to check host connectivity and mail servers for sending mail, so you must install postfix and other packages so that mon should work smoothly.

Installing and configuring Mon in Ubuntu

Now we will see how we can install and configure mon in Ubuntu.

Install process

$ sudo apt-get install mon

Start mon 

$ sudo /etc/init.d/mon start

Configuring Mon 

For configuring mon edit the configuration file /etc/mon/mon.cf

hostgroup servers 192.168.1.6  #There must be a one line gape after hostgroup line.

watch servers
    service ping
        interval 1m
        monitor fping.monitor
        period wd {Mon-Fri} hr {7am-10pm}
            alert mail.alert user@example.com
            alertevery 3m
        period wd {Sat-Sun}
            alert mail.alert user@example.com

First we define the hosts that we want to monitor. Then we create the a “watch” section for this hosts with only one service to monitor, the “ping” service. The service will be monitored using the monitor “fping.monitor” that you can find in “/usr/lib/mon/mon.d/fping.monitor”. Then we define the periods in which we want to monitor the hosts and the alert we will use if the monitor detects a fail. In this case we use the “mail.alert” agent that you can find in “/usr/lib/mon/alert.d/mail.alert”. An email to “user@example.com” will be sent if a fail is detected in the monitor.

Sample example for configuring mon for monitoring a host connectivity, mysql, apache and a web page.

hostgroup ping_services 192.168.1.6

hostgroup webservers itswork.com

hostgroup mysql_server localhost

hostgroup apache_service 192.168.1.6

watch ping_services
service ping
    interval 1m
    monitor fping.monitor
    period wday {Mon-Sun} hour {0-23}
        alert mail.alert user@example.com
        alertevery 1m

watch webservers example.com
service site
        interval 1m
        monitor http.monitor -p 80 -u /index.php
        period wday{Mon-Sun} hr {0am-24pm}
            alert mail.alert user@example.com

watch apache_service 192.168.1.6
service apache
        interval 1m
        monitor http.monitor
        period wday{Mon-Sun} hr {0am-24pm}
            alert mail.alert user@example.com

watch mysql_server
    service mysql
        interval 1m
        monitor mysql.monitor --username=mon --password=mon --database=mon localhost
        period wday {Mon-Sun}
            alert mail.alert -S "Host 1 Mysql Server is down!!" user@example.com
            upalert mail.alert -S "Host1 MYSQL server is back up" user@example.com
            alertevery 60s
            alertafter 3

For more help click here

Monit is a utility for managing and monitoring processes, files, directories and devices on a Unix system. Monit conducts automatic maintenance and repair and can execute meaningful causal actions in error situations. E.g. monit can start a process if it does not run, restart a process if it does not respond and stop a process if it uses to much resources. You may use monit to monitor files, directories and devices for changes, such as timestamps changes, checksum changes or size changes.  Monit will monitor a service and in case of any problems monit will will raise an email alert.

Install the package monit using apt on Ubuntu.

$ sudo apt-get install monit

First edit the file  /etc/default/monit and change startup=0 to  startup=1. The file should look like below text.

# Defaults for monit initscript
# sourced by /etc/init.d/monit
# installed at /etc/default/monit by maintainer scripts
# Fredrik Steen <stone@debian.org>
# You must set this variable to for monit to start

startup=1

# To change the intervals which monit should run uncomment# and change this variable.
# CHECK_INTERVALS=180

Edit the monit configuration file /etc/monit/monitrc and uncomment the following lines

$ sudo vim /etc/monit/monitrc

Start monit in background (run as daemon) and check the services at 2-minute intervals.

set daemon  120

You can set the alert recipients here, which will receive the alert for each service. The event alerts may be restricted using the list.

set alert abc@xyz.com                                   # receive all alerts
set alert hij@xyz.com only on { timeout }       # receive just service-

Monit has an embedded webserver, which can be used to view the configuration, actual services parameters or manage the services using the web interface.

set httpd port 2812 and
     use address localhost  # only accept connection from localhost
     allow localhost        # allow localhost to connect to the server and
     allow admin:monit      # require user 'admin' with password 'monit'

Next session in the configuration file is where the monit monitors the services,  for that we need to specify the service which needs to be monitored. A sample example for monitoring apache is as follows.

check process apache with pidfile /var/run/apache2.pid
    start program = "/etc/init.d/apache2 start"
    stop program  = "/etc/init.d/apache2 stop"
    if cpu > 60% for 2 cycles then alert
    if cpu > 80% for 5 cycles then restart
    if totalmem > 200.0 MB for 5 cycles then restart
    if children > 250 then restart
    if loadavg(5min) greater than 10 for 8 cycles then stop
    if 3 restarts within 5 cycles then timeout
    group server

For more examples click here
Next we will see some monit commonds.

To satrt monit

$ sudo /etc/init.d/monit start

To start the services which the monit is monitorin, sudo monit start all will start all the services in the monit configuration file, if specify a name insted of start all monit will start only the specified service.

$ sudo monit start all
$ sudo monit start apache

To get the status of monit services

$ sudo monit status

To get the summary of mont services

$ sudo monit summary

To stop all the services monitored my monit use stop all, or specify the name of the servive you need to stop

$ sudo monit  stop all
$ sudo monit stop apache

For more help click here

Introduction

When screen is called, it creates a single window with a  shell  in  it and then gets out of your way so that you can use the program as you normally would.  Then, at any time, you  can create new windows with other programs in them (including more shells), kill existing windows, view a list of windows, turn  output  logging  on and off, copy-and-paste text between windows, view the scroll back history, switch between windows in whatever manner you wish, etc.  All  windows  run  their  programs completely independent of each other.  Programs continue to run when their window is currently not visible and even when the whole screen session is detached from the user’s terminal.  When a program terminates, screen (per  default)  kills  the window  that  contained  it.  If this window was in the foreground, the display switches to the previous  window;  if  none  are  left,  screen exits.

 Usage

To start screen us the command screen.

$ screen

In the virtual terminal you can start any applications as you normaly done in normal terminals. Even if you close the virtual terminal the application will continue running in the back ground.

To list how many screens where on use the following command.

$ screen -ls
There are screens on:
        6475.pts-8.user-desktop        (Attached)
        6400.pts-6.user-desktop        (Attached)
2 Sockets in /var/run/screen/S-user.

To reattaches a screen session use the following command.

$ screen -d -r 6400.pts-6.user-desktop

To removed the distroyed sessions use the following command.

 $ screen -wipe

Install these packages with apt:

php5
php5-cli
php5-dev
php5-sqlite
php-pear

$ sudo apt-get install php5 php5-cli php5-dev php5-sqlite php-pear

Test if Apache and PHP are up and running typing in the browser:

http://localhost/

You should see something like:

Apache/2.0.55 (Ubuntu) PHP/5.1.2-1ubuntu1 Server at localhost Port 80

From the command line, as root:

$ sudo pear upgrade PEAR
$ sudo pear channel-discover pear.symfony-project.com

Edit /etc/php5/cli/php.ini and change the line:

memory_limit = 8M To memory_limit = 16M

Then

$ sudo pear install symfony/symfony
$ sudo pear install –alldeps http://phing.info/pear/phing-current.tgz

Using the command:

$ sudo pear config-show

we find the symfony libraries have been installed in:

$ php_dir/symfony/ /usr/share/php/symfony/ main libraries
$ data_dir/symfony/ /usr/share/php/data/symfony/ skeleton of symfony applications, default modules and configuration
$ doc_dir/symfony/ /usr/share/php/docs/symfony/ documentation

From the command line enter bellow command:

$ symfony -Vsymfony version 0.6.2

From the command line, as root:

$ mkdir /var/www/myproject
$cd /var/www/myproject
$ symfony init-project myproject
$ symfony init-app myapp

Edit /Virtual Host configuration file , and append the following at the end:

<VirtualHost 192.168.1.2:81>
ServerAdmin webmaster@localhost
ServerName servername.com
ServerAlias www.servername.com
DocumentRoot /var/www/project/web
Alias /sf /usr/share/php/data/symfony/web/sf
<Directory /var/www/project/web>
     Options FollowSymLinks MultiViews
     AllowOverride all
     Order allow,deny
     allow from all
</Directory>
</VirtualHost>

Using the command dd you can create swap file.

dd - convert and copy a file

First of all check the current swap size using the command ‘free’

$ free
Output
total       used       free     shared    buffers     cached
Mem:       1025620    1009140      16480          0       2252     465116
-/+ buffers/cache:     541772     483848
Swap:      2096440      18924    2077516

Create a directory called ’swap’ under slash ‘/’

$ sudo mkdir /swap

First creat a file using dd command

Creates a file of size 1GB

$ sudo dd if=/dev/zero of=/swap/swap.file bs=2048 count=524288

Format this file ‘/swap/swap.file’ using the command ‘mkswap’

$ mkswap /swap/swap.file

Activate the ’swap.file’ to the current swap space using the command ’swapon’

$ swapon /swap/swap.file

After the above command 1GB will be added to you are swap area.

You can check by the command ‘free’

$ free
             total       used       free     shared    buffers     cached
Mem:       1025620    1010660      14960          0       2620     465292
-/+ buffers/cache:     542748     482872
Swap:      3145008      18924    3126084

You can remove the swap area by using the command ’swapoff’

$ swapoff /swap/swap.file

If you get an error message like below.

perl: warning: Setting locale failed.
perl: warning: Please check that your locales settings:
        LANGUAGE = "en_JP:en",
        LC_ALL = (unset),
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory

Its because of not installing the language package or language installation problem. You have to install the language which you need. For it’s english, so I installed the package language-pack-en.

sudo apt-get install --reinstall language-pack-en

Recovering MySQL Password and Permission Problems

If you garble your GRANT commands or forget passwords and find that you don’t have access to the critical mysql table even as the root user don’t panic. You can access MySQL without password. Superuser can access MySQL using mysqld_safe command and you can change mysql password. Become the superuser on the operating system (we’re talking now about the Unix root, not the MySQL root) and kill the MySQL process.

Step : 1

Stop MySQL server

shahid@shahid:~$ sudo /etc/init.d/mysql stop
[sudo] password for shahid:
 * Stopping MySQL database server mysqld                                 [ OK ]
shahid@shahid:~$

Step : 2

Make sure MySQL is was not running

shahid@shahid:~$ ps aux | grep mysql
shahid   18751  0.0  0.0   3004   756 pts/5    S+   11:54   0:00 grep mysql
shahid@shahid:~$

Step : 3

Start Mysql using mysqld_safe

shahid@shahid:~$ sudo mysqld_safe --skip-grant-tables
nohup: ignoring input and redirecting stderr to stdout
Starting mysqld daemon with databases from /var/lib/mysql
mysqld_safe[19285]: started

Step : 4

Make sure you can now get access to the mysql database:

shahid@shahid:~$ mysql mysql
mysql>

Assign a password once again to the MySQL root user:

mysql> UPDATE mysql.user SET Password=PASSWORD('newpassword') WHERE User='root' AND Host='localhost';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)
mysql>

Step : 5

Terminate the MySQL server and restart it in the usual way. Make any necessary changes to the privileges through GRANT commands, running mysql as the root user.

shahid@shahid:~$ sudo /etc/init.d/mysql start
 * Starting MySQL database server mysqld                                 [ OK ]
 * Checking for corrupt, not cleanly closed and upgrade needing tables.
shahid@shahid:~$

MAC OS is one of the OS which gives impresive graphical ability and interface. My friends where planning to buy an apple laptop only because of its graphics, I myself attracted to MAC OS. There are some hardware compatibility issues for running MAC OS on Intel Hardware. So well other alternative to using MAC OS is either to purchase MAC hardware(which would be naturally expensive) and run full fledged MAC OS or you could tweak and customize your Ubuntu desktop to look more like MAC OS X.

Installing Cursor, GTK and Icon Theme

To install cursor,gtk and icon theme first download the package from the link given below :

http://rapidshare.de/files/38210507/MyTheme.tar.gz.html

To install the theme package we have downloaded fro the above link, go to (System -> Preferences -> Appearance) and click Install and point to our newly downloaded Mytheme.tar.gz archive.

This should start installing the theme package (Cursors/Icons/Theme) once installation is completed . Chose Customize in theme and click on Customize.

In this window in Icons chose LeopardX , in Controls Mac4Lin_GTK_Aqua_v0.3 , in Window Border Mac4Lin_GTK_Aqua_v0.3 and in Pointers White Cursor .

If you have followed the steps properly the theme and icons should have been installed , and you should be able to see the new theme applied to your default desktop.

Enabling Compiz Graphic Effects and installing Mac$lin Theme

First Step is to install compiconf-settings-managerusing apt-get

shahid@shahid-laptop:~$ sudo apt-get install compizconfig-settings-manager

Before customizing Compiz you have to change Appearance Preference to Extra ( System -> Preferences -> Appearence )

After completing above steps , you can customize compiz by going to System -> Preferences -> Advanced Desktop Effects Settings .

After this Install Emerald Theme Manager using apt-get

shahid@shahid-laptop:~$ sudo apt-get install emerald

After installation is over download MacOS X Emerald theme from this link : http://gnome-look.org/content/show.php/Mac4Lin+Leopard+Emerald+Theme?content=68409

Now open (System -> Preferences -> Emerald Theme Manager )

After Emerald theme manager opens click on import and point to the downloaded theme package from withing the Theme Manager , you will find Mac4Lin Theme listed select the theme , click on refresh and quit the application

Mav like Dock with Avant Navigator

After the above steps Install Avant Window Navigator.

Avant Windows Navigator is cool little tool that allows you to have a cute looking dock at the bottom of the screen . Even though AWN is still very buggy, still because it is so feature rich and cool looking you could install it .

To install AWN you need to add extra repositories, now adding any additional repository carries certain amount of risk of screwing up your system so follow these step at your own risk.

To add repository:

shahid@shahid-laptop:~$ echo "deb  http://ppa.launchpad.net/awn-testing/ubuntu hardy main" | sudo tee -a /etc/apt/sources.list
shahid@shahid-laptop:~$ echo "deb-src http://ppa.launchpad.net/awn-testing/ubuntu hardy main" | sudo tee -a /etc/apt/sources.list

After issuing above command type the following command to update your repositories :

shahid@shahid-laptop:~$ sudo apt-get update

and finally to install AWN issue the following command in the terminal window :

shahid@shahid-laptop:~$ sudo apt-get install awn-manager-trunk awn-extras-applets-trunk

Now after completing above mentioned steps AWN should be properly installed , To Launch AWN go to (Applications -> Accessories -> Avant Window Navigator )
Now you could customize AWN by choosing to add more applets , configuring 3D effects for AWN etc by going to AWN Manager ( System -> Preferences -> Awn Manager )

Though the theme which AWN comes with preinstalled is also good , you might like to try this it’s cool and very Mac like
http://rapidshare.com/files/71511920/Transparent.tgz.html
you could install this theme through AWN Manager go to (System->Preferences->AWN manager) and go to themes there and click on “Add” and point it to the downloaded theme.

You will see a confirmation dialog box that theme has been added properly. Close AWN Manager and start it again and chose the theme just installed and press apply button to make this theme default theme of AWN.
This is how my AWN Dock looks(with the above theme installed) like : -

Introduction

Memcached is a high-performance, distributed caching system. It is often used to speed up dynamic database-driven websites by caching data and objects in memory to reduce the number of times the database must be read.

Installing memcached

shahid@shahid-laptop:~$ sudo apt-get install memcached
shahid@shahid-laptop:~$ sudo apt-get install php5-memcache

After installing these two packages next step is to configure memcached.conf file. ( /etc/memcached.conf )Memcached.conf

After that edit the memecached.ini file. ( /etc/php5/apache2/conf.d/memcache.ini )

A sample memcache.ini file

; uncomment the next line to enable the module
extension=memcache.so
[memcache]
memcache.dbpath="/var/lib/memcache"
memcache.maxreclevel=0
memcache.maxfiles=0
memcache.archivememlim=0
memcache.maxfilesize=0
memcache.maxratio=0
session.save_handler = memcache
session.save_path = "tcp://192.168.1.1:11211?weight=1,tcp://192.168.1.2:11211"

There are some situations where you want to store instances of memcache on two servers. On this situaltion you want to set ’session.save_path’ as in the above example as comma separated.After that start memcached

shahid@shahid-laptop:~$ memcached -d   ==> Start memcache as a background process

shahid@shahid-laptop:~$ memcached -vv ==> Start memcached as a foreground process

For testing memcached you can start memcached using -vv option . If you start memcached using -vv option you can see stroing session on memcache on the terminal.

shahid@shahid-laptop:~$ memcached -vv
slab class   1: chunk size     96 perslab 10922
slab class   2: chunk size    120 perslab  8738
slab class   3: chunk size    152 perslab  6898
slab class   4: chunk size    192 perslab  5461
slab class   5: chunk size    240 perslab  4369
slab class   6: chunk size    304 perslab  3449
slab class   7: chunk size    384 perslab  2730
slab class   8: chunk size    480 perslab  2184
slab class   9: chunk size    600 perslab  1747
slab class  10: chunk size    752 perslab  1394
slab class  11: chunk size    944 perslab  1110
slab class  12: chunk size   1184 perslab   885
slab class  13: chunk size   1480 perslab   708
slab class  14: chunk size   1856 perslab   564
slab class  15: chunk size   2320 perslab   451
slab class  16: chunk size   2904 perslab   361
slab class  17: chunk size   3632 perslab   288
slab class  18: chunk size   4544 perslab   230
slab class  19: chunk size   5680 perslab   184
slab class  20: chunk size   7104 perslab   147
slab class  21: chunk size   8880 perslab   118
slab class  22: chunk size  11104 perslab    94
slab class  23: chunk size  13880 perslab    75
slab class  24: chunk size  17352 perslab    60
slab class  25: chunk size  21696 perslab    48
slab class  26: chunk size  27120 perslab    38
slab class  27: chunk size  33904 perslab    30
slab class  28: chunk size  42384 perslab    24
slab class  29: chunk size  52984 perslab    19
slab class  30: chunk size  66232 perslab    15
slab class  31: chunk size  82792 perslab    12
slab class  32: chunk size 103496 perslab    10
slab class  33: chunk size 129376 perslab     8
slab class  34: chunk size 161720 perslab     6
slab class  35: chunk size 202152 perslab     5
slab class  36: chunk size 252696 perslab     4
slab class  37: chunk size 315872 perslab     3
slab class  38: chunk size 394840 perslab     2
slab class  39: chunk size 493552 perslab     2
<3 server listening
<7 new client connection
<7 get 190c562b24186ff47914309b3ceaab95
>7 END
<7 set 190c562b24186ff47914309b3ceaab95 0 1440 0
>7 STORED
<7 connection closed.
<7 new client connection
<7 get 8c1f38e6f02939cea6a6563049e216c8
>7 END
<8 new client connection
<8 get 7925615c1ab9933cb33af0121881a82b
>8 END

Another method for checking whether memcached was enamble or not is to check the phpinfo() function. In the phpinfo page should contain memcache module.

First off, remember that fprint is not entirely stable, and may not work all the time. A list of supported devices is here, and the list of unsupported devices is here.

1. First thing to do is add the [third-party] fprint repository to your sources file ‘/etc/apt/sources.list'

# Fingerprint reader support (fprint)
deb http://ppa.launchpad.net/madman2k/ubuntu hardy main restricted universe multiverse

2. Next, update your sources and install fprint:

$sudo apt-get update
sudo apt-get install fprint-demo libfprint-dev libfprint0 libpam-fprint

3. Now you can enroll your fingers using either the terminal or a graphical user interface.
Terminal:

$ pam_fprint_enroll

GUI:

$ fprint_demo

4. Last thing to do is configure PAM so that the fingerprint reader can be useful. Open up your PAM authentication file and edit it:

$ sudo gedit /etc/pam.d/common-auth

5. Edit it to contain:

$ auth sufficient pam_fprint.so
$ auth required pam_unix.so nullok_secure

Enjoy your Fingerprint Reader Support

Steps 4 and 5 tell Ubuntu to check your fingerprint, and if that fails, then ask your password. This rule has some exceptions, one that I have encountered is on the login screen. I have to scan my fingerprint before typing my password. One thing I did notice is that when you use sudo in the terminal, it asks for your fingerprint, which I thought was pretty cool. One disadvantage is that anything using gksu does not seem to work properly, specifically because it does not tell you to scan your finger when needed.