Earlier today I was working with Dell Support to gather information about a broken system. It was suggested that I use their DSET utility to gather data and return a report. The problem is, DSET doesn’t natively support CentOS, so some tweaks were needed in order for it to run properly. In this post I’ll outline the changes I needed to make in order to run DSET on CentOS 6.2. Step 1: Download the DSET utility using wget. wget ftp://ftp.us.dell.com/FOLDER00481758M/1/dell-dset-3.2.0.141_x64_A01.bin Step 2: Create a working directory and extract the archive mkdir ~/dell tail -n+20 dell-dset-3.2.0.141_x64_A01.bin | tar -xzv -C ~/dell Note: If you get an error saying that the file is not in a valid archive format, you may need to alter the tail command slightly. Use the following command to determine the line at which the archive begins: awk '/^__ARCHIVE_BELOW__/ {print NR + 1; exit 0; }' dell-dset-3.2.0.141_x64_A01.bin Step 3: Trick the installer into thinking you’re running a supported OS Read more

Today I built some virtual machines on a KVM platform (Ubuntu 10.04 Server as the host). The three virtual machines are CentOS 5, i386 and will be used primarily for internal application testing. One of the requirements for using these machines in a virtual environment was configuring back-end console access from the host. The virtual machine management tools (virsh) provide custom commands to console into your guest machines, but the guest machines need to be configured to output to the proper console. This article outlines what customizations I made to the CentOS 5 virtual machines in order to console into them from the host using ‘virsh console ’ GRUB The first modifications that I needed to make were in GRUB. On CentOS the GRUB config file can be found at: /boot/grub/menu.lst. Below you’ll find the changes I made: default=0<br /> timeout=5<br /> #splashimage=(hd0,0)/grub/splash.xpm.gz<br /> serial --unit=0 --speed=115200<br /> terminal --timeout=10 console serial<br /> hiddenmenu Read more

Not long ago we rebuilt a number of servers within our production environment at work, migrating from FreeBSD to CentOS. One of the requirements in this migration was that we needed a server that would act as an SSH-only Jail on the new platform. This meant I needed to setup a system where users could SSH into a machine but the only thing they could do on that machine was SSH back out again. We used this as our “bounce” machine. Users would have outside access to their Desktops or other machines only by way of this secured SSH-only machine. The solution I found was a tool called “JailKit“, which allows you to create chroot jails is a very simple way. Below I’ll outline the requirements for installing JailKit and using it to create an SSH chrooted “Jail”. Step 1: Install JailKit I was unable to find an up to date package for JailKit on CentOS, so I did the following to install from source: Read more

Today I have finally found some time to catch up on my blogging. I’ve got a whole slew of backlogged information that I want to post, so hopefully my fingers (and my brain!) can keep up long enough to get it all published. The topic I wanted to start with today is mrepo: RPM Repository Mirroring made easy. Mrepo is a tool developed by Dag Wieers of rpmforge fame. If you’ve ever run an RPM based distribution (Red Hat, Fedora, CentOS, etc) you’ve very likely heard of Dag Wieers. He keeps the package machine running and provides those packages not otherwise available in the core repositories. I read that he developed this tool to help streamline the creation and deployment of RPM mirrors and network install servers, which he so often needed in dealing with clients. I used this exact setup to create and maintain an internal repository for our company which supplies network-based installation capabilities for Red Hat Enterprise 3, 4 and 5, CentOS 3, 4 and 5, Fedora 10 and 11, and openSUSE. Read more

The other day I blogged about how to extract the kernel and ramdisk from the DBAN downloadable image. These two files would be useful in the situation where you might want to PXE (network) boot a machine and have it wiped. (Something like this may be common prior to dispositioning a machine at work, or before you give an old machine away.) Whatever your reasons might be, I thought I would outline the steps that I have taken to install and configure PXE on a CentOS 5 installation. Installation yum install tftp-server DBAN Configuration After following my previous instructions on how to extract the DBAN PXE images, copy the two files (kernel.bzi and initrd.gz) to the /tftpboot/ directory. mkdir -p /tftpboot/dban<br /> cp kernel.bzi /tftpboot/<br /> cp initrd.gz /tftpboot/<br /> PXE Configuration You’ll also need to configure the PXE system to know what to launch/run when a specific command is given at boot. Read more