Citrix Systems' XenServer 5.0 Enterprise provided an impressive start to our server virtualization management Rolling Review. XenServer offers solid technology, simplified management, and a couple of neat twists that keep the game interesting.
Citrix does a number of things well with this release. It makes virtualization simple and straightforward, bundling XenServer Enterprise as a soup-to-nuts set of products in one box.
XenServer utilizes the Xen 3.2 hypervisor, a native 64-bit virtualization platform written in a svelte 50,000 lines of code with support for Intel VT and AMD-V chipset virtualization assist, and a number of performance enhancements that target Microsoft operating systems.
Initial installation and setup of Xen uses simple, menu-driven fields for the entry of environment parameters such as host name, license keys, IP addressing information, and permitting SSH access. We also used the basic interface to connect our first two hosts to our SAN.
All configuration and management functionality can be accessed from the command-line interface or via system menus, but most admins will fire up the XenCenter GUI management tool as soon as the first host is created. Linux CLI-shy Windows admins will feel right at home in XenCenter.
XenCenter let us create resource pools and assign XenServer hosts to those pools. And here's what we liked most: Citrix has implemented a Clustered Management Layer. That means no more dedicated, single-point-of-failure management server; any host in a resource pool can be promoted to the role of XenCenter host. Copies of system information, performance data, and logs are distributed across member servers. This greatly increases the utility of the high-availability feature set.
ACCESS IN A JIFFY
XenCenter offers quick access to a console view, storage assignments, network, performance, logs, and general information. Admins can create custom data fields and tags for individual virtual machines; tagging is a drop-down item under the General tab. This is useful as your VM count rises, giving admins flexibility in searching, sorting, or modifying VMs based on site-driven custom terms.
Using resource pools or virtual machine host tools, local storage and network settings can be deployed to all running VMs.
Physical-to-virtual, or P2V, migration caused a hiccup on our 64-bit Windows 2003 app server because of, well, user error. After reading the manual, we realized having a large scratch volume (an empty volume) is a good plan, and auto-mount needs to be enabled for the P2V conversion to complete. Auto-mount allows the Xen virtual hard drive-formatted virtual disk to be recognized by the operating system so the converter can write the disk image and finish the job.
The wizard-driven P2V tool, XenConvert, provides solid error logging. The P2V conversion runs with no need to reboot; XenConvert creates a point-in-time snapshot of a running production server.