Tech Notes

Ruby on Rails for RHEL 5

Here is the quick and dirty Ruby on Rails setup for Redhat Enterprise Linux v5 with MySQL.
Using yum install ruby and mysql. The command below does not list all the required packages, but due to dependencies, the additional packages will be installed (or should be - this is all from memory).


Move an LVM-based virtual machine to another host

For those running Xen on servers with no back-end SAN, the following instructions detail the steps necessary to move an LVM-based virtual machine to a new physical host. There may be more elegant ways to achieve this, but this is what worked for me.
Environment
Ok, so let’s set the scene:

vmhost is a RHEL 5 server [...]


Install phpMyAdmin

phpMyAdmin is web-based PHP application for managing MySQL databases. It is fairly easy to install and configure.
Download the latest stable version from the phpMyAdmin web site, and extract it to a location of your choice. I prefer to keep the installation outside of the web root and use an apache alias to reference [...]


Mount an ISO file

You can mount a CD or DVD image in Linux so that it appears like a regularly inserted disc. Use the following command:
prompt# mount Fedora-8-x86_64-DVD.iso /mnt/isofile/ -o ro,loop=/dev/loop0
Ensure that the /mnt/isofile directory exists before trying to mount the ISO to that location.


VNC over SSH

Sometimes it is useful to manage a Linux server remotely using VNC. A simple and secure method for doing so is to tunnel the VNC connection using Secure Shell. The following instructions have been tested on Redhat Enterprise Linux 5 AS.
On the server side:
First, we need to ensure the vncserver is actually running. [...]