Demandforce currently has two Xen servers hosting virtual machines for development, devxen1 and devxen2. Their IPs are 172.16.1.11 and 172.16.1.12 respectively. More Xen servers will be added in the future to accommodate further growth.
Managing virtual machines consists of starting, stopping, and rebooting them. Sometimes a virtual machine may seem stuck, and is inaccessible via the virtual machine's assigned IP. But accessing it via the Virtual Machine Manager will often "wake up" the virtual machine, and make it accessible via the assigned IP.
Using Virtual Machine Manager
To start, you need to know which Xen server the virtual machine is running on. Login to salesforce, and view the report "IP Address List w/Eng-Virtual Machines" to obtain this information. You should be able to access this report via the clicking this link. Search for the virtual machine you want to access, and then look up the Eng - Machine Name it runs on, which should be either devxen1 or devxen2.
Once you know which Xen server the virtual machines runs on, connect to that Xen server with vncviewer. If you don't already have vncviewer, you can download tightvnc viewer from http://www.tightvnc.com/download.html
Open up vncviewer, and connect to either 172.16.1.11:1 or 172.16.1.12:1 depending on which Xen server the virtual machine is hosted on. Please ask firstname.lastname@example.org for the password if you don't know it. But it's probably one you already know.
Once connected, start the Virtual Machine Manager if it isn't already started. You can start it by clicking Applications->System Tools->Virtual Machine Manager:
The right click on localhost, and select Connect:
Finally, right click on the virtual machine you want to access, and select Open:
This will open a window to the console of the virtual machine. From there, you can login, restart, or shutdown the virtual machine:
If you cannot see the bottom of the window, hold down the Alt key, and then you can drag the virtual machine console window higher to see the bottom of the window.
Once you click inside the virtual machine's console, they keyboard and mouse will be captured by the virtual machine instead of the vncviewer's window manager. To exit the virtual machine console, click Ctrl-Alt and keyboard and mouse control will be returned to the vncviewer's window manager.
Once you are done, please close the virtual machine console window.
For Linux machines, you may or may not see a GUI window. But you can still use the Virtual Machine Manager to start any Linux virtual machines as needed. Usage should be self-explanatory from right clicking the Linux virtual machine listed in the Virtual Machine Manager.
Using Command Line Tools
There are two command line tools available to manage VMs, xm and virsh. xm is the legacy tool that was developed by xensource. The future of this toolset is unknown since xensource has been acquired by Citrix, which has their own set of CLI tools for managing VMs. virsh uses libvirt, which is being developed by Redhat, and will be the tool they will support moving forward. The syntax of the two are almost identical, but it is useful to know both due to some compatibility issues. The man page for xm and virsh has all the options available for both. Below is a cheat sheet with common commands.
Power off (Akin to pulling the power cord from a machine)
So basically the two commands are the same for most operations you'd use, other than to start a VM which is create for xm and start for virsh.
It's better to use virsh by default as that is what Redhat will support moving forward. However if the VM has a USB license key, you need to use xm...