Questions[open-source](server)

We are planning a slow migration from VMware (and third party apps) to open source alternatives (free would be great).

Basically, we want to start with some little cluster lab, then migrate the production environment (35+ ESX, 1500 VMs) in the future (X years, there is no hurry... yet)

Our bet is CentOS/Scientific Linux as the operating system of choice and KVM as the hypervisor.

The vCenter alternative we are thinking about, is Convirt, but we don't know if all the features we use in VMware will be supplied by Convirt (HA, DRS, clustering,...), or we should try some other alternatives (any ideas?)

The monitoring is being replaced by Nagios and the backup/replication will be replaced by some scripting magic.

So, is there anyone who can give us some advices, or in a similar situation?

PS.- This is my first question in serverfault, and my english level is not so good, but I hope the question is understandable.

PS2.- I forgot to mention that we provide also VDIs. And the alternative we've been thinking is Spice.

I don't know if this belongs on SF, SU or SO... let's try SF first.

I'm looking for a "live help" system for website which uses Jabber/XMPP as a backend... so that website visitors could click a "Chat Now" button, and using AJAX, chat with operators who are already set up using Jabber accounts. Something very much like J-Livesupport but without a jabber server (I already have one) and preferably OSS/free.

Openfire's Fastpath Webchat is perfect except you must use Openfire's Spark client. No dice there.

Before I build my own, anyone know of anything out there?

I believe every system administrator is used to open source by now. From Apache to Firefox or Linux, everyone uses it at least a little bit.

However, most open source developers are not good in marketing, so I know that there are hundreds of very good tools out there that very few people know.

To fill this gap, share your favorite open source tool that you use in your day-to-day work.

*I will post mine in the comments.

I'm looking for a good open-source alternative to active directory that can handle:

• Authorization/Authentication
• Group Policy
• Replication and Trust Monitoring

In addition, are there any consolidated systems out there that handle these responsibilities?

Edit: Since a lot have asked for more details, I am trying to offer a service setting up an infrastructure for organizations, hardware/software setups, right now I am looking at a Linux stack, both desktops and servers, however a hybrid stack is possible, and I am investigating alternatives.

Recently I've been playing around with Ubuntu 9.04 on one of my work systems. The only real bump in the road that keeps it from being being used as my main workstation is that I cannot find a suitable solution for an email client that works with our Exchange 2007 servers. Ideally, I would like to implement a solution that meets the following criteria:

• The client is open source (and free)
• The solution does not require the installation of software on the Exchange server
• The solution does not require enabling POP or IMAP on the Exchange server

From what I've seen so far, it sounds like I may be out of luck (at least for the time being) though I just wanted to present the question to the community and see if anyone had any ideas.