###AutoFS###
Features:
 1. Automatically mounts file systems (NFS, local, SMBFS, etc.) upon I/O request


Requirements:
 1. autofs-*rpm must be installed

/etc/auto.master - primary configuration file
 - also contains mount points and their mappings

/etc/sysconfig/autofs - default startup directives

Note: AutoFS must be running in order to auto-mount directories


Task: 
 1. Create an automount for /shares, which will mount /nfs1 & /nfs2
  a. update /etc/auto.master - '/shares /etc/auto.shares'
  b. cp /etc/auto.misc /etc/auto.shares
  c. update the rules in /etc/auto.shares
  d. Create AutoFS tree: /shares/
  e. Restart the autofs service
  f. Unmount: /nfs1 & /nfs2 if necessary
Note: Do NOT auto-mount directories that are already mounted
  g. Test access to AutoFS controlled directory
   g1. 'ls -l /shares/nfs1'

Note: syntax for auto-mount files is as follows:
<mount-point>  [<options>]  <location>
nfs1    -fstype=nfs 192.168.75.199:/nfs1

Thanking You
Hope U Like it...

Windows Server 2008

Orientdb NoSQL part2

Python 3.4.1

Install OrientDB Document Graph

Netbeans IDE

Vtiger CRM Database

Apache Web Server
 Features:
  1. WWW Web Server
  2. Modular

Tasks:
 1. Install Apache 2.2x
  a. httpd*rpm

/etc/httpd - top-level configuration container on RH5
/etc/httpd/conf - primary configuration directory

/etc/httpd/conf/httpd.conf - primary Apache configuration file

/etc/httpd/conf.d - drop-in configuration directory, read by Apache upon startup

 2. Explorer: /etc/httpd/conf/httpd.conf

  a. HTTPD runs as: apache:apache
  b. Apache maintains, always, a 'main' server, which is independent of Virtual Hosts. This server is a catch-all for traffic that doesn't match any of the defined virtual hosts.

  c. <Directory> directive governs file system access.
Note: The primary Apache process runs as 'root', and has access to the full file system. However, <Directory> directive restricts the web-user's view of the file system.

  d. Test access to '.ht*' files from web root

  e. ErrorLog logs/error_log - default error log file for ALL hosts
  f. logs/access_log - default log file for default server

 Note: Every directory, outside of the 'DocumentRoot' should have at least one: <Directory> directive defined.

 3. Start Apache and continue to explore
  a. service httpd start
root        31324     1      0 10:17 ?        00:00:00 /usr/sbin/httpd
apache   31326 31324  0 10:17 ?        00:00:00 /usr/sbin/httpd
apache   31327 31324  0 10:17 ?        00:00:00 /usr/sbin/httpd
apache   31328 31324  0 10:17 ?        00:00:00 /usr/sbin/httpd
apache   31329 31324  0 10:17 ?        00:00:00 /usr/sbin/httpd
apache   31330 31324  0 10:17 ?        00:00:00 /usr/sbin/httpd
apache   31331 31324  0 10:17 ?        00:00:00 /usr/sbin/httpd
apache   31332 31324  0 10:17 ?        00:00:00 /usr/sbin/httpd
apache   31333 31324  0 10:17 ?        00:00:00 /usr/sbin/httpd

Note: Parent Apache runs as 'root' and can see the entire file system
Note: However, children processes run as 'apache' and can only see files/directories that 'apache:apache' can see

 4. Create an Alias for content outside of the web root (/var/www/html)
  a. Alias /testalias1 /var/www/testalias1
     <Directory /var/www/testalias1>
    AllowOverride Non
    order allow,deny
    allow from all
     </Directory>

 5. Ensure that Apache will start when the system boots
  a. chkconfig --level 35 httpd on && chkconfig --list httpd

Virtual Hosts Configuration:
 Features:
  1. Ability to share/serve content based on 1 or more IP addresses
  2. Supports 2 modes of Virtual Hosts:
   a. IP Based - one site per IP address
   b. Host header names - multiple sites per IP address


Tasks:
  1. Create IP Based Virtual Hosts
   a. ifconfig eth0:1 192.168.75.210
   b. Configure the Virtual Host:

<VirtualHost 192.168.75.210>
    ServerAdmin webmaster@linuxcbtserv4.linuxcbt.internal
    ServerName site1.linuxcbt.internal
    DocumentRoot /var/www/site1
    <Directory /var/www/site1>
        Order allow,deny
        Allow from all
    </Directory>
    CustomLog logs/site1.linuxcbt.internal.access.log combined
    ErrorLog logs/site1.linuxcbt.internal.error.log
</VirtualHost>

  c. Create: /var/www/site1 and content
  d. Update: /etc/httpd/conf/httpd.conf with VHost information


 2. Create Name-based Virtual Hosts using the primary IP address
  a. /etc/httpd/conf/httpd.conf: 
   NameVirtualHost 192.168.75.199:80

<VirtualHost 192.168.75.199:80>
    ServerAdmin webmaster@linuxcbtserv4.linuxcbt.internal
    ServerName site3.linuxcbt.internal
    DocumentRoot /var/www/site3
    <Directory /var/www/site3>
        Order allow,deny
        Allow from all
    </Directory>
    CustomLog logs/site3.linuxcbt.internal.access.log combined
    ErrorLog logs/site3.linuxcbt.internal.error.log
</VirtualHost>
 

###Apache with SSL Support###
 Features:
  1. Secure/Encrypted communications

 Requirements:
  1. httpd
  2. openssl
  3. mod_ssl
  4. crypto-utils (genkey) - used to generate certificates/private keys/CSRs
    a. also used to create a self-signed certificate

Tasks:
  1. Install the requirements
   a. mod_ssl - module for Apache, which provides SSL support
   yum -y install mod_ssl
    /etc/httpd/conf.d/ssl.conf - includes key SSL directives

   b. crypto-utils - provies /usr/bin/genkey

  2. Generate SSL usage keys using: genkey
   a. genkey site1.linuxcbt.internal - creates text-gui interface

  3. Update /etc/httpd/conf.d/ssl.conf to reference the new keys (public/private)

  4. Restart the HTTPD server
   a. service httpd restart
   b. httpd -S
 
  5. Test HTTPS connectivity
   a. https://192.168.75.199

Note: For mutliple SSL sites, copy the: /etc/httpd/conf.d/ssl.conf file to distinct files, that match your distinct IP-based VHosts.


Thanking You
Hope U Like it....

Own Website

Vtiger Open Source

Install Vtiger CRM

Tortoise installation SVN

Notepad++ install

Ubuntu Server 12.04

• BIOS stands for Basic Input/output System
• Performs some system integrity checks
• Searches, loads, and executes the boot loader program.
• It looks for boot loader in floppy, cd-rom, or hard drive. You can press a key (typically F12 of F2, but it depends on your system) during the BIOS startup to change the boot sequence.
• Once the boot loader program is detected and loaded into the memory, BIOS gives the control to it.
• So, in simple terms BIOS loads and executes the MBR boot loader.

• MBR stands for Master Boot Record.
• It is located in the 1st sector of the bootable disk. Typically /dev/hda, or /dev/sda
• MBR is less than 512 bytes in size. This has three components 1) primary boot loader info in 1st 446 bytes 2) partition table info in next 64 bytes 3) mbr validation check in last 2 bytes.
• It contains information about GRUB (or LILO in old systems).
• So, in simple terms MBR loads and executes the GRUB boot loader.

• GRUB stands for Grand Unified Boot loader.
• If you have multiple kernel images installed on your system, you can choose which one to be executed.
• GRUB displays a splash screen, waits for few seconds, if you don’t enter anything, it loads the default kernel image as specified in the grub configuration file.
• GRUB has the knowledge of the filesystem (the older Linux loader LILO didn’t understand filesystem).
• Grub configuration file is /boot/grub/grub.conf (/etc/grub.conf is a link to this). The following is sample grub.conf of CentOS.

• As you notice from the above info, it contains kernel and initrd image.
• So, in simple terms GRUB just loads and executes Kernel and initrd images.

• Mounts the root file system as specified in the “root=” in grub.conf
• Kernel executes the /sbin/init program
• Since init was the 1st program to be executed by Linux Kernel, it has the process id (PID) of 1. Do a ‘ps -ef | grep init’ and check the pid.
• initrd stands for Initial RAM Disk.
• initrd is used by kernel as temporary root file system until kernel is booted and the real root file system is mounted. It also contains necessary drivers compiled inside, which helps it to access the hard drive partitions, and other hardware.

• Looks at the /etc/inittab file to decide the Linux run level.
• Following are the available run levels
  • 0 – halt
  • 1 – Single user mode
  • 2 – Multiuser, without NFS
  • 3 – Full multiuser mode
  • 4 – unused
  • 5 – X11
  • 6 – reboot
• Init identifies the default init level from /etc/inittab and uses that to load all appropriate programs.
• Execute ‘grep initdefault /etc/inittab’ on your system to identify the default run level
• If you want to get into trouble, you can set the default run level to 0 or 6. Since you know what 0 and 6 means, probably you might not do that.
• Typically you would set the default run level to either 3 or 5.

• When the Linux system is booting up, you might see various services getting started. For example, it might say “starting sendmail …. OK”. Those are the runlevel programs, executed from the run level directory as defined by your run level.
• Depending on your default init level setting, the system will execute the programs from one of the following directories.
  • Run level 0 – /etc/rc.d/rc0.d/
  • Run level 1 – /etc/rc.d/rc1.d/
  • Run level 2 – /etc/rc.d/rc2.d/
  • Run level 3 – /etc/rc.d/rc3.d/
  • Run level 4 – /etc/rc.d/rc4.d/
  • Run level 5 – /etc/rc.d/rc5.d/
  • Run level 6 – /etc/rc.d/rc6.d/
• Please note that there are also symbolic links available for these directory under /etc directly. So, /etc/rc0.d is linked to /etc/rc.d/rc0.d.
• Under the /etc/rc.d/rc*.d/ directories, you would see programs that start with S and K.
• Programs starts with S are used during startup. S for startup.
• Programs starts with K are used during shutdown. K for kill.
• There are numbers right next to S and K in the program names. Those are the sequence number in which the programs should be started or killed.
• For example, S12syslog is to start the syslog deamon, which has the sequence number of 12. S80sendmail is to start the sendmail daemon, which has the sequence number of 80. So, syslog program will be started before sendmail.

• User (u): The owner of file
• Group (g): Other user who are in group (to access files)
• Other (o): Everyone else

• Read (r)
• Write (w)
• Execute (x)

• Read access on a file allows you to view file
• Read access on a directory allows you to view directory contents with ls command

• Write access on a file allows you to write to file
• Write access on a directory allows you to remove or add new files

• Execute access on a file allows to run program or script
• Execute access on a directory allows you access file in the directory