Showing posts with label Linux General. Show all posts
Showing posts with label Linux General. Show all posts

Saturday, April 12, 2008

Kickstart installation of Linux

Using kickstart, a system administrator can create a single file containing the answers to all the questions that would normally be asked during a typical Red Hat Linux installation.

Steps

1. Creating the Kickstart File :The kickstart file is a simple text file, containing a list of items.

(a) Command Section:

  • autostep(optional)
  • auth or authconfig (required)
  • bootloader (required)
  • clearpart (optional)
  • device (optional)
  • deviceprobe (optional)
  • driverdisk (optional)
  • firewall (optional)
  • install (optional)
  • interactive (optional)
  • keyboard (required)
  • lang (required)
  • langsupport (required)
  • lilo (replaced by bootloader)
  • lilocheck (optional)
  • logvol (optional)
  • mouse (required)
  • network (optional)
  • part or partition (required for installs, ignored for upgrades)
  • raid (optional)
  • reboot (optional)
  • rootpw (required)
  • skipx (optional)
  • text (optional)
  • timezone (required)
  • upgrade (optional)
  • xconfig (optional)
  • volgroup (optional)
  • zerombr (optional)
  • %include

(b) Package Selection

(c) Pre-installation Script:You can add commands to run on the system immediately after the ks.cfg has been parsed. This section must be at the end of the kickstart file (after the commands) and must start with the %pre command.

(d) Post-installation Script :This section must be at the end of the kickstart file and must start with the %post command.

2. Making the Kickstart File Available

A kickstart file must be placed in one of the following locations:
On a boot diskette
On a boot CD-ROM
On a network

3. Make the installation tree available. An installation tree is a copy of the binary Red Hat Linux CD-ROMs with the same directory structure. If you are performing a CD-based installation, insert the Red Hat Linux CD-ROM #1 into the computer before starting the kickstart installation.
If you are performing a hard-drive installation, make sure the ISO images of the binary Red Hat Linux CD-ROMs are on a hard drive in the computer.
If you are performing a network-based (NFS, FTP, or HTTP) installation, you must make the installation tree available over the network.

4. Starting a Kickstart Installation: To begin a kickstart installation, you must boot the system from a Red Hat Linux from following

(a) Boot diskette

(b) CD-ROM #1 and Diskette

(c) With Driver Disk

Kickstart Configurator

Kickstart Configurator allows you to create a kickstart file using a graphical user interface, so that you do not have to remember the correct syntax of the file.
To use Kickstart Configurator, you must be running the X Window System. To start Kickstart Configurator, select the Main Menu Button (on the Panel) => System Tools => Kickstart, or type the command /usr/sbin/redhat-config-kickstart.

Friday, March 21, 2008

How to MD5

The program md5sum is designed to verify data integrity using the MD5 (Message-Digest algorithm 5) 128-bit cryptographic hash. MD5 hashes used properly can confirm both file integrity and authenticity.
In terms of integrity, an MD5 hash comparison detects changes in files that would cause errors. The possibility of changes (errors) is proportional to the size of the file; the possibility of errors increase as the file becomes larger. It is a very good idea to run an MD5 hash comparison check when you have a file like an operating system install CD that has to be 100% correct.
In terms of security, cryptographic hashes such as MD5 allow for authentication of data obtained from insecure mirrors. The MD5 hash must come from a secure source (an HTTPS page) of an organization you trust. While security flaws in the MD5 algorithm have been uncovered, MD5 hashes are generally sufficient for casual use. Please refer to the secure UbuntuHashes page for the official list of Ubuntu MD5 hashes.

MD5SUM on Linux
Most Linux distributions come with the md5sum utility so installation is usually unnecessary. We are going to use the Ubuntu 6.10 Desktop install CD for the following example:
First go to the correct directory to check a downloaded iso file
#cd download_directory
Then run the following command from within the download directory.
#md5sum ubuntu-6.10-desktop-i386.iso
The md5sum should print out a single line after calculating the hash:
b950a4d7cf3151e5f213843e2ad77fe3 ubuntu-6.10-desktop-i386.iso
Compare the hash (the alphanumeric string on left) that your machine calculated with the corresponding hash on the UbuntuHashes page. When both hashes match exactly then the downloaded file is almost certainly intact. If the hashes do not match, then there was a problem with either the download or a problem with the server. You should download the file again from either the same mirror, or from a different mirror if you suspect a server error. If you continuously receive an erroneous file from a server, please be kind and notify the webmaster of that mirror so they can investigate the issue.