I am looking for an virtualization solution for the following criteria:

1. automated/scripted creation/deletion/destroying of VMs fulfilling some conditions
conditions are: initially there will be set of 20 VMs (Linux, Windows, mix). 20 users will use those VMs, do some minimal works like light development practices, browsing, video playback etc. When they log-off or shutdown, those VMs will be destroyed, and new set of 20 VMs will be created as fresh new system (like steadystate), but with same network (ip addressing) and user parameter. Whole thing should be automated using scripts. The server needs to run multiple instances of virtual desktops (with GUI) with ability to create, destroy and recreate these virtual machines on demand.

My question: Which solution is good to go - VMware, hyper-V, vagrant, KVM, VirtualBox? People are telling me to go for vagrant, with docker. Need some helpful suggestions.

2. Logging of server usage, VMs usage, statistics

The server needs to be able to log its usage, peak times, average load. Also, it must be aware of active and inactive sessions. Clients should connect via VNC or X2GO to the "next available" VM. That's why we need to log "free" or "available" sessions. Only one client should work inside a VM at a time. No virtual machine should be shared between two or more clients. Do I need separate server to log and monitor, and any specific tools like zabbix, nagios, vmware operation manager (if I go for vmware solution).

3. Access/IP addressing

Do I need to have public IP address for all the VMs and physical server to access all via VNC/X2Go? If possible with one public IP on the physical server, will there be any chance for hacking, session hijacking etc? Since multiple users will be logging on those VMs through internet using one public IP (if possible using one IP).

4. Misc. requirement -

highly scalable (upto 1000 users/VMs), suggestion on full GUI remote access protocol - VNC, RDP, X2Go.
Any web interface available to do remote access like microsoft RDweb but also support accessing linux?
Possibility of Audio streaming through remote session? (heard x2go supports audio, not yet tested).

n/m.
why do I bother.

I have been looking at XenServer for virtualization. It does have a learning curve (I'm still learning it as well). But some of the features I like about it that there is an application that you can load on another system called XenCenter that will let you has a complete GUI console to manage the server from. Take a look at this site and see if it what you are looking for.

http://www.xenproject.org