This toolkit provides an interactive, programmer-friendly interface to VMware's VProbes facility. VProbes is a safe, dynamic technology for instrumenting software running in virtual machines, and the software stack itself.
Weasel is an Operating System installer similar to Redhat's Anaconda. When you insert the ESX Installation DVD, this program guides you through the steps of network configuration, disk selection, etc. Or it can perform an automated install based on a script similar to Redhat kickstart scripts.