Installing CentOS 6

Please note: This instruction was created for my personal use. Feel free to follow it, but I am not responsible for any problems or data loss!

Download the network install CD, which can be found at: ftp://ftp.tudelft.nl/pub/Linux/centos.org/6/isos/x86_64/CentOS-6.5-x86_64-netinstall.iso. Check the MD5 sum by running md5sum on CentOS-6.5-x86_64-netinstall.iso and compare the result to the MD5 sums at: ftp://ftp.tudelft.nl/pub/Linux/centos.org/6/isos/x86_64/md5sum.txt

Boot from the network install CD. Make sure you have at least 768MB of memory available, or you will not be able to create a custom harddisk layout.

Skip the disk checking after booting the install CD. Set the installation language to English. Select URL for the Installation Method and enter the following URL: ftp://ftp.tudelft.nl/pub/Linux/centos.org/6/os/x86_64/, after configuring the network. Use auto configuration, if possible.

• Select the U.S. English keyboard layout.
• Select Basic Storate Devices (unless you are installing to a SAN).
• Enter the hostname you would like to use (do not add the domain name).
• Select the correct timezone and make sure System uses UTC is enabled.
• Enter the root password.
• Select Create Custom Layout and create a primary partition for the OS and one for swap (create a swap partition as large as the amount of memory you have).
• Use the provided boot loader configuration.
• Select the Minimal installation option.
• Wait for the installation to finish.
• Reboot the system.

• Add the EPEL repository by running: rpm -Uvh https://fedora-archive.ip-connect.vn.ua/epel/6/x86_64/epel-release-6-8.noarch.rpm
• Add the noatime option to all ext3/ext4 filesystem options in /etc/fstab
• Edit /boot/grub/menu.lst and remove the rhgb and quiet options
• Edit /etc/rc.local and add the following line: /usr/bin/setterm -blank 0 This will prevent the screen from going black, which may be helpful in case of a kernel problem.
• Update the system: yum upgrade
• Add a normal user, to log in as: useradd -m username
• Set a password: passwd username
• Edit the sudoers file by running: visudo
  • Comment out the line: Defaults    requiretty
  • Comment out the line: Defaults   visiblepw
  • Enable users in the group wheel to use sudo, by uncommenting: %wheel  ALL=(ALL)       ALL
• Add the normal user to the wheel group: usermod -a -G wheel username
• Make sure root cannot log in via ssh by changing /etc/ssh/sshd_config:
  • PermitRootLogin without-password
  • This will disable logging in as root, via ssh, but it is still possible to log in as root using SSH public key authentication.
• Disable the firewall (when in a secure network), by running: chkconfig iptables off; chkconfig ip6tables off
• Add the following line to /etc/sysconfig/network:
  • NOZEROCONF=yes
• Install the following packages:

yum install -y irqbalance sysstat iotop strace tcpdump lsof ntp man man-pages man-pages-overrides mlocate wget openssh-clients perl iptraf-ng bind-utils vim-enhanced atop

• Enable irqbalance: chkconfig irqbalance on (only useful on an SMP system)
• Set up /etc/ntp.conf:

driftfile /var/lib/ntp/drift
restrict default kod nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery
restrict 127.0.0.1 
restrict -6 ::1
server 0.nl.pool.ntp.org
server 1.nl.pool.ntp.org
server 2.nl.pool.ntp.org
server 3.nl.pool.ntp.org

• Change /etc/ntp/step-tickers:

0.nl.pool.ntp.org
1.nl.pool.ntp.org

• Enable ntpdate and ntpd: chkconfig ntpdate on; chkconfig ntpd on
• Reboot the system to activate all changes

-- Ivo van Geel - 17 Oct 2012