Category Archives: Linux

CentOS 5.5 Installing Hyper-V Linux Integration Components v2.1

The first thing I recommend doing on your Linux VM server is running yum update. If you run ‘yum update’ after the installation you could see:
Kernel Panic after Yum Update – CentOS with Hyper-V Linux Integration Components, which would probably just add a few extra headaches.

Next, go to Microsoft, download and extract the Linux Integration Services package.

Next, install the Linux Integration Components:
Load the Linux Integration Components v2.1 iso into your VM.
When logged in as root, run:

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Adding a Directory to Linux PATH Environment Variable

During custom compiling of applications, sometimes you will see error messages like the following:

make: depmod: Command not found

That doesn’t necessarily mean your computer doesn’t have something installed, but it could mean the program just couldn’t find it.
Here is how to fix it:

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Kernel Panic after Yum Update – CentOS with Hyper-V Linux Integration Components

I am runnning CentOS 5.5 in a VM on Hyper-V. I created a fresh installation. I then installed Hyper-V Linux Integration Components. After Installing them I ran yum update.

After running a “yum update”, and rebooting I received this error.

Unable to access resume device (/dev/VolGroup00/LogVol01)
mount: could not find filesystem '/dev/root'
setuproot: moving /dev failed: No such file or directory
setuproot: error mounting /proc: No such file or directory
setuproot: error mounting /sys: No such file or directory
switchroot: mount failed: No such file or directory
Kernel panic - not syncing: Attempted to kill init!

During the yum update process, it updated my kernel. Kernels that are installed after Hyper-V Linux Integration Components don’t always mesh well together. Here is how I fixed my issue.

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Run Rackspace Cloud Server locally on Hyper-V

Here is how I ran a copy of my Rackspace cloud server locally on my Hyper-V 2008 R2 Server. Why would you want to do that you ask? Well, there are many reasons. For example, I want to run all my applications in a test/staging environment before I push them live. I want to test all updates to my servers before I push them out live, testing large processes out without wasting money on CPU/bandwidth before running them live, etc. It is very nice to have a near exact copy of what you are running on rackspace cloud servers locally.

Part of the problem was I didn’t have any spare servers laying around that I could install linux and Xen on but I already had a Hyper-V server. This would allow me to run a linux VM, but how do you get a Rackspace cloud server backup running in Hyper-V.

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Centos 5 linux / PHP prerequisites

If you are building PHP from source on a new server, you might run into few linux prerequisites before you can complete a ./configure. You might not need all of these, or you might need more depending on how much stuff you are including in your configure line. Here is how to fix a good majority of the issues you might run into on Centos 5.

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ClamAV Update Breaks Mail Delivery

Postfix + ClamAV + SpamAssassin + Amavisd-New

As we all know, ClamAV versions older than 0.95 stopped working yesterday. This was announced some time ago by ClamAV, but caught most people (Myself and Devin) by surprise when mail flow stopped cold on our email servers. ClamAV pushed down an update that broke older versions, forcing sysadmins to either disable Antivirus, or update ClamAV to a more recent version.

We were running a very old version of ClamAV, 0.91.2-1~volatile1, from 2007. An upgrade was long overdue anyway. Here are 2 ways to fix it.

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Installing lighttpd with mod_magnet on centos x86_64

Installing lighttpd was pretty simple, however while setting up this wordpress site I wanted to enable WP Super Cache. In order to run Super Cache in full mode on lighttpd we need lighttpd with mod_magnet.

mod_magnet requires that lua be install. For some reason lighttpd doesn’t appear to like lua when it is installed via yum. So I had to compile it by source.

mkdir /root/installers
cd /root/installers
mkdir lua
cd lua

wget http://www.lua.org/ftp/lua-5.1.4.tar.gz
tar xvfz lua-5.1.4.tar.gz
cd lua-5.1.4

Note: if you are using x86_64 you will need to make this modification

vim src/Makefile

change

CFLAGS= -O2 -Wall $(MYCFLAGS)

to

CFLAGS= -O2 -Wall -fPIC $(MYCFLAGS)

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