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If you use the Xen Project Hypervisor, you have a rare opportunity to share what you've learned with your peers.  On September 15, 2014 in New York City, we will be holding our second annual Xen Project User Summit -- and we want you to join us there!

We are looking for talk proposals which will be of interest to other Xen Project users.  Subjects of interest include (but are not limited to):

  • How you use our project’s software in your datacenter or lab
  • How you integrate the Xen Project hypervisor in your solution or cloud
  • How you control the software with custom scripts or utilities
  • Why you chose Xen Project software instead of some other hypervisor
  • How much you time or money you saved by using our software
  • Where you’d like to see our project go in the future

Also, we’d welcome talks about:

  • Features of recent releases and how you use them
  • New projects building on Xen Project software which could open new avenues for end users (like the work around GPU virtualization, cloud operating systems like MirageOS, and additional architectures like ARM)
  • Instructive HowTo sessions to educate attendees about implementing particular capabilities within the software
  • The use of related products and projects (like XenServer, Xen Orchestra, CloudStack, etc.) to make our software even more powerful in the datacenter

 

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Quite a few years ago I made a rather nice living coding things up. Some were big projects used in regulated industries, and others a bit more mundane, but in all cases I tried to ensure confusion over what the point of the project was could be minimized. After all, the last thing I wanted was a prospective user or partner investing in something which wouldn't meet their needs.

Fast-forward to today, and as the XenServer evangelist I want to accomplish the same task, but scope is a bit broader. I want people to be using XenServer, and I want many tens of thousands of them doing so. By the same token, I also want those same users to know they are using XenServer, and not something else. After all, its equally bad if someone thinks they're using XenServer when they aren't, or are using something different when they are in fact using XenServer.

A perfect case in point is the confusion over what "Xen" and "XenServer" are. For years I've heard people who want XenServer referring to it as "Xen" and occasionally as "Xen Server". While many of those people aren't technical, and for them the distinction is largely irrelevant, the fact of the matter is the distinction does matter. For example, if someone is working on a project which they wish to integrate with XenServer, it does them no good to see references to "Xen" all over XenServer content, or to look at examples which reference "Xen"; even if the actual code is for XenServer and not "Xen". Even more significant is that, with the move of the "Xen" hypervisor to the Linux Foundation last year, what was once known as the "Xen" hypervisor has now become the Xen Project hypervisor.

All of which gets me to Apache CloudStack. Apache CloudStack is a wonderful solution for anyone looking to get a cloud up and running quickly, particularly those looking to have multiple hypervisors in their cloud and managed from a single console. Unfortunately, Apache CloudStack is also a perfect example of the problem I'm highlighting here. Within the UI, documentation and code, the term "Xen" and "XenServer" are used interchangeably, when in reality Apache CloudStack only supports XenServer; or more precisely XAPI based toolstacks for the Xen Project hypervisor. To resolve this problem, and to pave the way for the Xen Project hypervisor to become a full citizen of Apache CloudStack, I put forth a proposal to distinguish and disambiguate "Xen" and "XenServer". The design document can be found on the CloudStack wiki. To give an example of the cost of resolving these things after the fact; the initial patch consisted of over 17,000 lines, subsequent patches will be needed following extensive testing, all with the result of no new functionality. If you're interested in following the progress of this activity, please do so on the CloudStack mailing lists, and on the wiki.

The point I hope I'm making here is that when there is the potential for confusion, someone will eventually become confused. If you are working on something which references "Xen" or "XenServer", I hope you'll take a few minutes to see if you're using the right references and if not plan on clarifying things for your customers and users. To assist, please refer to this handy-dandy list:

  • "Xen" is a bare metal hypervisor which since April 2013 is a Linux Foundation Collaborative Project and has been renamed as the "Xen Project hypervisor". You can find more information about Xen Project at http://xenproject.org. Importantly, while "Xen" was the name Citrix used for the hypervisor, when "Xen" moved to the Linux Foundation, Citrix granted the Linux Foundation the limited rights to use the word "Xen" as part of the "Xen Project".
  • Citrix continues to use the "Xen" mark in connection with a variety of products such as XenApp and XenDesktop, so if you are working on a project with integration into other Citrix products, and are referring to them as "Xen", you risk further confusion with the hypervisor work occurring with both XenServer and the Xen Project.
  • XAPI, or XenAPI, is a toolstack for use with the Xen Project hypervisor and is a sub-project under Xen Project at the Linux Foundation. You can find more information about XAPI at http://xenproject.org/developers/teams/xapi.html
  • XenServer is a packaged virtualization solution from Citrix which in June 2013 was made completely open source. XenServer uses the Xen Project hypervisor and API support is provided via XAPI. Commercial support for XenServer is available from Citrix, and open source activities can be found on xenserver.org.
  • XCP, or Xen Cloud Platform, was a previous attempt at making XenServer open-source. With XenServer becoming open source in June of 2013, XCP development transitioned to XenServer.       
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Next Generation High Density App Servers Don't Require Scrapping Your Hypervisor

Recently, I sat in a conference session extolling the seemingly endless virtues of Linux Containers.  I heard claims that hypervisors were old hat: ancient bloated engines which rely on inefficient replication of a large operating system stack in order to serve up applications.  The speaker painted a picture of a future where hundreds of applications are virtualized on each piece of hardware.  "What is really needed," glowed the speaker, "is a lightweight, efficient means of serving up application: containers."

Containers are cool, but not a panacea

Containers share the same kernel as the host, so they are not burdened with the extra memory and CPU cycles it costs to replicate a full operating system stack in a hypervisor scenario.  Compared to hypervisor-generated virtual machines, containers can be fast and lean.  But they are also limited.  

Since Linux containers share the same kernel as the host, it is impossible to run Windows.  Or FreeBSD. Or NetBSD.   Or another version of the Linux kernel.  Or another Linux distribution which requires a different kernel.  All of those scenarios are best handled by a real hypervisor.  And the security aspect of hypervisors is huge, worthy of a separate blog entry of its own.  Still, if you need an environment within your organization where many workloads can leverage a single kernel environment, containers can be a viable solution.

However, some of the most vocal container advocates insist that these problems relating to containers are really application problems in disguise.  Issues about kernel support and security are the results of improper application design, they claim.  When we raise the bar on applications so that they are based solely on access to application servers, then the objections to containers will melt away -- and so will hypervisors, for the most part.  Or that's what some of these advocates claim, at least.

The death of the hypervisor is greatly exaggerated

But is there another scenario which could answer the call for highly responsive and lightweight virtual instances which does not use the container solution?  Maybe one that can actually leverage the flexibility and security which is part and parcel with most hypervisors?

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I have been working with Clouds since before the coining of the term itself (back then, the startup I was working for called it "Agile Infrastructure"; now it's known as "IaaS"). From the very beginning, a frequent blocker to adoption has been the question of security. "We can't go to the Cloud because it is simply not secure," goes the complaint.

Well, I'm here to say it's bunk -- pure bunk. There is NO new security problem in the Cloud.

There is, in fact, a security problem in external Clouds -- but it is already in your data center right now.

If you take a truly secure system and place it in an external or hybrid cloud, it will remain secure. Simply exposing a secure system to a larger number of potentially hostile assailants is not enough to make it vulnerable. No, a truly secure system is designed to remain that way even during escalating pressure.

The problem is that very few of our current systems are truly secure. They rely heavily on the notion that threats are few behind the corporate firewall, so they don't need to have air-tight security. That concept is -- and always was -- a mistake. And now that conditions are changing in the Cloud, the inappropriate assumption is causing major headaches. The leaks in the boat are becoming apparent now that it is finally in the water.

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Open Source Cloud Projects to Watch

Posted by on in Open Source

We often have our heads down looking at the projects we regularly work on (Apache CloudStack and Xen Project) and don't always pay attention to the other cool things going on in the open source world. So once and a while it's good to poke your head up olut of the clouds and take a look at some of the awesome projects being developed in the open source community. These projects are very promising and especially usefully for cloud comptuing.  

Hybrid Cloud => Segregated Workloads

I am not convinced of the hybrid cloud scenario as espoused by many cloud pundits. I think it's more theoretical then the common place. What I do think happens is that organizations are using the public cloud and private cloud simultaneously with different applications in each and will continue to do so. That's why I like some of these tools that help users manage mutliple clouds (hopefully one of them will be Apache CloudStack ;) from a single tool. 

Scalr 

Scalr InterfaceOne of my favorite projects is Scalr which gives users an easy-to-use menu-driven interface (See screenshot to the right) that enables them to deploy applications on multiple clouds. I have seen Scalr in use on a number of CloudStack clouds as well as being used to manage Amazon Web Services. Their template system makes cloud deployments a point-and-click proposition. 

jclouds 

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Open@Citrix

Citrix supports the open source community via developer support and evangeslism. We have a number of developers and evangelists that participate actively in the open source community in Apache Cloudstack, OpenDaylight, Xen Project and XenServer. We also conduct educational activities via the Build A Cloud events held all over the world. 

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