What is Xen, and why is it cool?

Posted by virtualization.info Staff   |   Saturday, February 19th, 2005   |  

Quoting from Nathan Torkington at O’Reilly Developers Weblogs:


I got into Xen a few weeks ago, and I’m loving that they’re getting lots of attention. But most folks don’t know what they are and why their product is so cool. Allow me to shed light on the matter …
Xen is like the Mach microkernel, where you can have multiple operating systems running at once and a thin kernel handles switching between them and managing device access. This thin layer in Xen is called the hypervisor, and is analogous to the Mach microkernel. It provides an idealized hardware layer that you port your OS to, and in return you get the ability to run multiple operating system instances at once (e.g., run two copies of Redhat’s latest, one copy of the Novell Desktop, and an OpenBSD), freeze and restore snapshots of a running OS, and more.

What you can’t do with Xen is run Windows on it–that’s always going to be VMware’s niche (at least until Intel’s VM technology becomes ubiquitous). But Xen makes a whole lot of situations possible that are slow or impossible at the moment. Two applications that are working well for Xen: testing and server load balancing. If you’re working on your app and want to test it on a staging server, it’s no fun to reboot, or negotiate time on a shared staging server, and it’s way less fun to rebuild if your app hoses the staging server. The Xen way, you run your development OS and your staging OS on your machine at the same time and switch from one to the other when you need to. If the staging server gets borked, you delete that running OS and reload from a saved stable snapshot.

In the server room, it’s often easier and more secure to manage a single service on a running machine. The more ways into a box, the less defensible it is and the more risk for damage and service downtime if the box is compromised. So run Xen and use one OS instance per service. If a service is compromised, only that service is compromised. If you experience high load, say due to Slashdotting, you can easily reconfigure machines to run different services. (You can rdist the snapshot of an OS running that service and then bring it up on however many machines you need).

The potential for Xen is great. We’re going to feature them at OSCON because their technology is just so cool. Lots of companies like RedHat and HP are very interested in what Xen makes possible, because the hypervisor enables things that seemed like wishful fantasy a few years ago. I loved my time meeting with one of the company’s founders and playing with Xen–they’re very smart engineers with their heads screwed on right. There’s obviously a lot of work to be done in making Xen friendlier to install, getting more tools around the administration of Xen, etc., so the interest and involvement of companies with big budgets is a good thing. They’ll help move Xen from the research lab where it was born to data centers and developer desktops where it can be ubiquitous and useful.

So look for lots of action from Xen. I expect the next versions of Novell, HP, etc.’s offerings will feature Xen support (either standard or as an alternate kernel shipped with the distro). I hope there’ll be a great distro like Ubuntu or Gentoo offering a Xen install as well as a solo install. This will give everyone a painless way to do some very cool things and open the door for even cooler things down the line.



blog comments powered by Disqus


virtualization.info Newest articles
Release: VMware vRealize Log Insight 4.5

June 13th, 2017

Log Insight is a log aggregation, management and analysis tool, that VMware first introduced in 2013 and considered a competitor of Splunk.
Yesterday VMware announced the release of version 4.5, available for…

Release: VMware vRealize Automation 7.3

June 6th, 2017

Today VMware announced the latest release of its cloud management platform vRealize Automation, former vCloud Automation Center.
VMware vRealize Automation 7.3 release notes can be found at this link.

The…

Paper: Introducing the NSX-T Platform

February 9th, 2017

“We see greater potential strategic opportunity in NSX over the next decade than our franchise product vSphere has had for the past decade.”
said VMware’s CEO Pat Gelsinger talking about…

Paper: VMware vSphere Virtual Machine Encryption Performance

November 22nd, 2016

Encryption of virtual machines is something that has been requested for years by the security community. VMware continued to postpone its implementation due to the negative operational impact that many…

Quest Software leaves Dell

November 1st, 2016

In September 2012 Dell announced to have completed the acquisition of Quest Software, a Californian company with an history in systems management, security, business intelligence and, falling back in our…

Citrix announces Q3 2016 results

October 21st, 2016

Citrix announced its financial results for third quarter 2016.
The revenues for the second quarter were $841 million for an increase of 3% compared to Q3 2015.
Net income was $132…

Release: VMware vSphere 6.5 & Virtual SAN 6.5

October 19th, 2016

2016 edition of VMworld US has been quite turbulent, on the other hand during VMworld Europe, happening these days in Barcelona, the company announced a few more products for the…

Release: VMware vRealize Log Insight 4.0

October 18th, 2016

Log Insight is a log aggregation, management and analisys tool, that VMware first introduced in 2013 and now is usually compared with Splunk.
Yesterday VMware announced Log Insight’s new major…

Release: Windows Server 2016 with support for Window Server & Hyper-V containers

October 13th, 2016

Yesterday Microsoft announced the general availability of Windows Server 2016 which the company defines as a cloud-ready OS.
Beside fancy definitions, one of the most relevant perks of this release…

Release: Oracle VM 3.4.2

September 22nd, 2016

During Oracle OpenWorld 2016 the company released version 3.4.2 of its enterprise virtualization solution.
Oracle VM is available for both x86 and SPARC based processor architectures and uses the Xen hypervisor…

VMworld US 2016 Wrap-up

September 1st, 2016

Today was the last day of VMware’s flagship conference VMworld in Las Vegas, an highly controversial edition which left a good chunk of the audience disoriented if not properly disappointed….

Gartner releases its Magic Quadrant for Cloud Infrastructure as a Service for 2016

August 11th, 2016

Last week Gartner updated its Magic Quadrant for Cloud Infrastructure as a Service (IaaS) for the year 2016. The Magic Quadrant for the year 2015 was released in May last year…

Release: Ansible Tower 3 by Red Hat

August 2nd, 2016

Ansible is one of the four main players in the automation market, younger then the well known Chef and Puppet, has been launched in 2013 in Durham, N.C. and acquired…

IBM announces earnings for Q2 2016

July 19th, 2016

Yesterday IBM announced its results for Q2 2016.

If we compare with the same quarter in 2015 earnings per share, from continuing operations, decreased 22%. Net income, from continuing operations,…

 
Monthly Archive