Archive for the ‘Redhat’ Category.
Most of you know that you need to save your iptables changes using service iptables save before rebooting on Redhat, or else you’lllose all your rules. I brought up the setting IPTABLES_SAVE_ON_STOP to “yes” in /etc/sysconfig/iptables-config. There’s some pretty cool settings in there . Read on for details.
Continue reading ‘/etc/sysconfig/iptables-config in RHEL/CentOS’ »
Simple enough, add an exclude line to the end of your [main] section in /etc/yum.conf , and you are done. Your yum.conf should look something like this:
[main]
cachedir=/var/cache/yum
keepcache=0
debuglevel=2
logfile=/var/log/yum.log
exactarch=1
obsoletes=1
gpgcheck=1
plugins=1
installonly_limit=3
exclude=gdm pidgin
This will prevent upgrades of the gdm package as well as pidgin. The list of apps in the exclude should be space sepeated. Shell wildcards ( * ? ) can also be included.
In Redhat, Fedora, or Centos Linux, you’re required to type command such as “service sshd start” and the main problem is NO auto complete for service command by default. Yes I admitted I’m lazy guy!
So how to set AUTO COMPLETE “service” command on Redhat/Centos? Read Below.
Continue reading ‘Redhat/Fedora: Auto Complete for the “service” command’ »
One way to find your version of Red Hat is to type the following:
cat /etc/redhat-release
Continue reading ‘How to tell what version of Red Hat you have installed’ »
A “service” is a program that starts automatically when you start your computer, and runs in the background. For example, the “network” service sets up your connection to the Internet and keeps it running correctly.
There are two ways to manage services in Fedora, one using the graphical tools, and one using only the command line. If you’re not in a graphical environment, use the command line method.
Continue reading ‘How to manage services in Fedora/Redhat’ »
A cluster usually refers to a group of computers connected together so that more computer power, e.g., more MIPS (millions instruction per second), can be achieved or higher availability (HA) can be obtained.
Beowulf, Super Computer for the “Poor” Approach
Most super computers in the world are built on the concept of parallel processing–high-speed computer power is achieved by pulling the power from each individual computer. Made by IBM, “Deep Blue”, the super computer that played chess with the world champion Garry Kasprov, was a computer cluster that consisted of several hundreds of RS6000s. In fact, many big time Hollywood movie animation companies, such as Pixar, Industrial Light and Magic, use computer clusters extensively for rendering (a process to translate all the information such as color, movement, physical properties, etc., into a single frame of picture).
In the past, a super computer was an expensive deluxe item that only few universities or research centers could afford. Started at NASA, Beowulf is a project of building clusters with “off-the-shelf” hardware (e.g., Pentium PCs) running Linux at a very low cost.
In the last several years, many universities world-wide have set up Beowulf clusters for the purpose of scientific research or simply for exploration of the frontier of super computer building.
Continue reading ‘Building a Two-Node Linux Cluster with Heartbeat on Red Hat’ »
So say that you are running out of resources and can’t buy a new Ethernet card for the system, or there’s not enough slots for another one. No problem, whatever the reason, we can assign two or more IP addresses to our linux box using only one NIC.
I’ll do it in Fedora.
And you’re done. So simple na. You can add up to 255 different IP addresses to one linux machine using this technique
Who’s afraid of SELinux? Well, if you are, you shouldn’t be! Thanks to the introduction of new GUI tools, customizing your system’s protection by creating new policy modules is easier than ever. In this article, Dan Walsh gently walks you through the policy module creation process.
A lot of people think that building a new SELinux policy is magic, but magic tricks never seem quite as difficult once you know how they’re done. This article explains how I build a policy module and gives you the step-by-step process for using the tools to build your own.
Continue reading ‘A step-by-step guide to building a new SELinux policy module’ »
These are some decent guides for securing your Red Hat Linux 5 system provided by the US Government’s NSA. Enjoy
Hardening Tips Pamphlet for the Red Hat Enterprise Linux 5
Guide to the Secure Configuration of Red Hat Enterprise Linux 5
