Greetings,
It's me again to mention OpenVZ. I maintain some CentOS OS Templates for OpenVZ and update them on about a monthly basis. I usually don't have trouble having an OS Template out for a new release on the day of the release (example CentOS 4.7 and 5.2).
You can find them here:
http://download.openvz.org/template/precreated/contrib/
You can actually find a number of OS Templates for CentOS on the openvz.org website but I believe mine (as you can see in the "contrib" directory) are the only ones that are refreshed periodically. As I write this, the current ones are:
centos-4-i386-default-4.7-20081013.tar.gz 13-Oct-2008 22:40 108M centos-4-x86_64-default-4.7-20081013.tar.gz 13-Oct-2008 22:43 115M centos-5-i386-default-5.2-20081013.tar.gz 13-Oct-2008 22:47 117M centos-5-x86_64-default-5.2-20081013.tar.gz 13-Oct-2008 22:50 124M
Those OS Templates probably have a little more software in them than some of the smaller ones (I like having links, mc, nano, and screen) and yes yum is installed.
While I don't have experience with any, it is my understanding that some/many commercial hosting providers that offer "VPS" accounts that are OpenVZ (or Parallels Virtuzzo Containers) based often have somewhat dated, minimalistic setups... often without yum even installed... which can be very problematic. I know the IRC #centos channel on freenode really doesn't like to get questions from cut rate account VPS users running CentOS containers, especially if they are missing some somewhat common packages and don't have an easy way to install them (no yum).
Speaking of OpenVZ OS Templates but getting a little off topic with non-CentOS info, an OpenVZ community member (Robert Nelson) has been working on a new OS Template build system he calls "vzpkg2" and "pkg-cacher" (a modified version of Debian's apt-cacher) that makes it easy to build OS Templates for Fedora, CentOS, Debian and Ubuntu... 44 different combinations when you consider the various distro release versions and both the i386 and x86_64 arches. While vzpkg2 is still hasn't been added as a stock OpenVZ package, I've been testing it and it works great. It is easy to build YOUR OWN OS Templates from scratch and in a network efficient way (with the help of pkg-cacher). I was able to build all 44 OS Templates in just a couple of hours with a broadband connection.
What's an OS Template? Basically it is install media for a Linux distribution from which you can make a container in about a minute. I did an interview with Robert Nelson and wrote up a more complete explanation on OS Templates which you can find here:
http://www.montanalinux.org/robert-nelson-interview.html
I really recommend using CentOS as an OpenVZ host node distro. Why? You can find out in the OpenVZ HOWTO I wrote for the CentOS wiki here:
http://wiki.centos.org/HowTos/Virtualization/OpenVZ
Questions, comments, suggestions? Feel free to email me directly (dowdle@montanalinux.org) or this list.
TYL,