TUT200: Virtualization Technology in the Data Centre
Today’s problems in addition to security, identity, etc. also include the same old thing to do with underutilized servers, overprovisioned datacenters, and inefficient use of our IT infrastructure componentry. Virtualization is one approach to reduce this inefficiency. The other area it addresses is high availability and business continuity.
In virtualization, emerging trends are standards, open source, federated identity, automated policy-based provisioning, and virtualization of workload on commodity platforms.
IT stuff will be operated as services. Some you will operate yourself, and some you will consume from others. In general, you will consume ubiquitous services like power, water, datacomm, payroll, order fulfillment, email, crm, erp. You will operate strategic benefit services like design, scm, derivative trading models, manufacturing, erp, crm. This varies of course depending on what type of business you are in and what types of services are strategic for your business.
Sugar CRM supports various methods of consuming their software. First you can outsource it to them. Second you can install it and run it yourself. Third you can buy it on an appliance and run it yourself but get it maintained by Sugar.
A key focus is to make IT manageable. If you want to go to utility-based computing using virtualization you need management tools to really leverage it. Novell has most of this stuff available in Enterprise 10 Linux, along with ZenWorks.
Reasons for virtualization:
Devide physical server into multiple vms for higher utilization.
Unite physical servers into one large vm for scale and availability.
Flexible management of your workloads (migrate your services to lower-loaded machines).
Available solutions: User mode linux, VMware, Virtual Iron (combine physical machines in to larger virtual ones or subdivide into smaller ones) and Xen (paravirtualization). VMware is the most mature, and Xen is the fastest. VMware and Virtual Iron have the best management tools right now. Xen requires modified guests or hardware assistance via vt technology in processors. Xen 3.0 adds the ability to run unmodified guests on vt processors and the ability to dedicate physical devices to guests while hiding them from the hosts.
OSes that work on Xen without vt assist include Linux, NetBSD, FreeBSD, NetWare viX, and they are working on Solaris.
With Xen, there is a host OS, but it stands beside the guests, rather than underneath them. It just provides physical device redirection, but doesn’t actually virtualize the processor or anything like that. The performance impact on guest vms in Xen is minimal.
The idea of NetWare going forward is to Xen-virtualize it on SLES, to allow you to maintain it indefinitely if required, so that hardware vendors don’t have to keep developing drivers. Linux and Windows drivers get developed quickly and then vendors move to NetWare drivers, maybe, if they have time. Xen lets them concentrate on Linux and Windows and let Xen take care of NetWare.
If you want to test this today the virtualized NetWare is not available, but you can virtualize OES Linux. Use the SUSE Enterprise Beta 8 as a host, and get the latest Xen for SUSE release from novell forge because the one on SUSE Beta 8 is not the latest.
Guest configurations are stored in /etc/xen. The files are kind of similar to grub menu.lst files. disk images for VMs can either be on shared storage, or can just be subdirectories on Domain0’s filesystem. If you want to get migration capability, you need shared storage that can be mounted by multiple hosts.