After the server is built, the management tools must be installed on a separate workstation. These tools are Java-based, available for Windows and Linux. Installation on a Windows XP system and a Fedora Core 6 x86_64 workstation proved simple, as was connecting to the newly built XenEnterprise host. When firing up the management tool for the first time, the admin is prompted to enter a master password. In this fashion, the same management console can be used to control multiple XenEnterprise servers without requiring separate authentication each time a different server is accessed.

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The management application is well laid out, with a top pane showing the server itself and all VMs running on that server. Each of these entries is accompanied by resource utilization information that gives at-a-glance performance monitoring of each VM and the host server, which is a nice touch. All VM configuration and server configuration occurs in the bottom pane, which is also where the VM consoles are accessed, although they can be popped out of the main window into windows of their own.

Building VMs on XenEnterprise is simple but requires specific OS templates be present on the server itself for non-Windows VMs. When the Linux pack is installed, templates are presented for most major distributions from Red Hat and Suse, as well as for Debian Sarge. These templates are necessary because XenEnterprise relies on paravirtualization to run these VMs: They don't truly run in their own emulated server space. Windows guests are handled differently: It's possible to boot a Windows VM from a Windows Server 2003 install CD and build the VM from scratch.

Tripped up again
My first VM installation on XenEnterprise flushed out a few problems. I initially configured a new Red Hat Enterprise Linux 4 Update 4 VM with 1GB of RAM and an 8GB disk. Once I started the new VM and linked to the console, XenEnterprise's customized Red Hat Enterprise Linux 4 installer was already running. I ran through the familiar installer, opting to do the installation via NFS. When configuring the NFS mount to find the required installation packages, I inadvertently mapped to an NFS directory containing the x86_64 version of Red Hat Enterprise Linux 4 Update 4, not the i386 version. Rather than throwing an error, the management application and the server itself locked up tight, requiring a reboot. After that, I was able to build Red Hat Enterprise Linux 4 Update 4 and Windows Server 2003 VMs with no issues, as long as I was sure not to use 64-bit versions.

XenEnterprise doesn't claim to support 64-bit VMs, so the fact that they didn't run on the server wasn't a surprise. But the server locking up certainly was -- a warning dialog here is really mandatory.