You can use this script to get notified of YUM updates. Just add it to your crontab and wait for the emails: Create the script file in “/usr/bin/yum-update-notification.sh” and make it executable. Make sure to change the variables at the top of the script and also the packages to check
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How to Stress-Test a WebServer (Siege, Gatling and basic Maths)
It’s important to know how many people a website server can handle at a given time. Tools like Siege and Gatling are open-source tools that can help. Stress testing tools such as Siege and Gatling make a given number of TCP connections to the target webserver. A typical web browser
Read moreBasic Website Stress-Test with Gatling2
This article demonstrates how to run a basic website stress-test using Gatling2. See the previous article on how to install Galting2. In this example, i’m running Gatling2 from “/root/gatling2/”. Create a file in the “/root/gatling2/user-files/simulation/” directory called “MyTest1.scala” (/root/gatling2/user-files/simulation/MyTest1.scala). Add the following content to it: import io.gatling.core.Predef._ import io.gatling.core.session.Expression import
Read moreInstall Gatling Website Stress-Tester on CentOS 6/Redhat 6
Gatling is a website stress-testing tool. It runs on Java so you need to install JRE7. This article is based on CentOS 6.4. Note that “good” documentation for Gatling basically doesn’t exist. The website (http://gatling-tool.org/) doesn’t have much information and i can’t find anything significant elsewhere. So here are my
Read moreDisplay a message when users login (MOTD)
To display a message to all users who log into your server, you should edit the file “/etc/motd” as root. #### This is the Web Server for AGIX. #### Note that this message is displayed ‘after’ someone has logged in, not before. Nothing further needs to be done. Just try
Read moreSudo Without a Password & Restricted Commands/Groups – CentOS and Redhat
This article explains how to use SUDO without being prompted for the password. We can restrict which users and/or groups can do this. As root, edit the file “/etc/sudoers”. Add the line: agix ALL=(ALL) NOPASSWD: ALL The above means that the user “agix” can use sudo without being prompted for
Read moreUsing Varnish to “Cap” Server Load – Redhat/CentOS
This article demonstrates how to Cap or Limit the load on a Web Server using Varnish. The idea here is to specify a timeout value which, if exceeded, the web surfer will be diverted to a customised error page. By adjusting the timeout value, the administrator can choose what kind
Read moreInstalling Debian on a Raspberry Pi using a Mac OSX
This article explains how to install Debian on a Raspberry Pi. You will need to download the Debian distro prepared for the Pi. Get it from here: Downloads TIP: Use a fast SD card. They come rated: Class Minimum Speed Class 2 2 MB p/s Class 4 4 MB p/s
Read moreInstall Cobbler on CentOS/Redhat
This article explains the installation process for Cobbler on CentOS 6.4 64bit. Install Cobbler and the other services. TIP, you need the EPEL repo available: yum install cobbler* tftp* httpd Edit the “/etc/xinetd.d/tftp” file to enable the TFTPd service: service tftp { socket_type = dgram protocol = udp wait =
Read moreVarnish Cache as a Load Balancer on CentOS/Redhat
This article explains how to configure the Varnish Cache as a load balancer. In other words, you have two Web Servers with a Varnish server in-front of them. As illustrated below: Internet -> Varnish -> Web Server 1 -> Web Server 2 Varnish does it’s load balancing in a round-robin
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