Category Archives: Xen

Exalogic, EC2-on-OVM, Oracle Linux: The Oracle Open World early recap

Among all the announcements at Oracle Open World so far, here is a summary of those I was the most impatient to blog about.

Oracle Exalogic Elastic Cloud

This was the largest part of Larry’s keynote, he called it “one big honkin’ cloud”. An impressive piece of hardware (360 2.93GHz cores, 2.8TB of RAM, 960GB SSD, 40TB disk for one full rack) with excellent InfiniBand connectivity between the nodes. And you can extend the InfiniBand connectivity to other Exalogic and/or Exadata racks. The whole packaged is optimized for the Oracle Fusion Middleware stack (WebLogic, Coherence…) and managed by Oracle Enterprise Manager.

This is really just the start of a long linage of optimized, pre-packaged, simplified (for application administrators and infrastructure administrators) application platforms. Management will play a central role and I am very excited about everything Enterprise Manager can and will bring to it.

If “Exalogic Elastic Cloud” is too taxing to say, you can shorten it to “Exalogic” or even just “EL”. Please, just don’t call it “E2C”. We don’t want to get into a trademark fight with our good friends at Amazon, especially since the next important announcement is…

Run certified Oracle software on OVM at Amazon

Oracle and Amazon have announced that AWS will offer virtual machines that run on top of OVM (Oracle’s hypervisor). Many Oracle products have been certified in this configuration; AMIs will soon be available. There is a joint support process in place between Amazon and Oracle. The virtual machines use hard partitioning and the licensing rules are the same as those that apply if you use OVM and hard partitioning in your own datacenter. You can transfer licenses between AWS and your data center.

One interesting aspect is that there is no extra fee on Amazon’s part for this. Which means that you can run an EC2 VM with Oracle Linux on OVM (an Oracle-tested combination) for the same price (without Oracle Linux support) as some other Linux distribution (also without support) on Amazon’s flavor of Xen. And install any software, including non-Oracle, on this VM. This is not the primary intent of this partnership, but I am curious to see if some people will take advantage of it.

Speaking of Oracle Linux, the next announcement is…

The Unbreakable Enterprise Kernel for Oracle Linux

In addition to the RedHat-compatible kernel that Oracle has been providing for a while (and will keep supporting), Oracle will also offer its own Linux kernel. I am not enough of a Linux geek to get teary-eyed about the birth announcement of a new kernel, but here is why I think this is an important milestone. The stratification of the application runtime stack is largely a relic of the past, when each layer had enough innovation to justify combining them as you see fit. Nowadays, the innovation is not in the hypervisor, in the OS or in the JVM as much as it is in how effectively they all combine. JRockit Virtual Edition is a clear indicator of things to come. Application runtimes will eventually be highly integrated and optimized. No more scheduler on top of a scheduler on top of a scheduler. If you squint, you’ll be able to recognize aspects of a hypervisor here, aspects of an OS there and aspects of a JVM somewhere else. But it will be mostly of interest to historians.

Oracle has by far the most expertise in JVMs and over the years has built a considerable amount of expertise in hypervisors. With the addition of Solaris and this new milestone in Linux access and expertise, what we are seeing is the emergence of a company for which there will be no technical barrier to innovation on making all these pieces work efficiently together. And, unlike many competitors who derive most of their revenues from parts of this infrastructure, no revenue-protection handcuffs hampering innovation either.

Fusion Apps

Larry also talked about Fusion Apps, but I believe he plans to spend more time on this during his Wednesday keynote, so I’ll leave this topic aside for now. Just remember that Enterprise Manager loves Fusion Apps.

And what about Enterprise Manager?

We don’t have many attention-grabbing Enterprise Manager product announcements at Oracle Open World 2010, because we had a big launch of Enterprise Manager 11g earlier this year, in which a lot of new features were released. Technically these are not Oracle Open World news anymore, but many attendees have not seen them yet so we are busy giving demos, hands-on labs and presentations. From an application and middleware perspective, we focus on end-to-end management (e.g. from user experience to BTM to SOA management to Java diagnostic to SQL) for faster resolution, application lifecycle integration (provisioning, configuration management, testing) for lower TCO and unified coverage of all the key parts of the Oracle portfolio for productivity and reliability. We are also sharing some plans and our vision on topics such as application management, Cloud, support integration etc. But in this post, I have chosen to only focus on new product announcements. Things that were not publicly known 48 hours ago. I am also not covering JavaOne (see Alexis). There is just too much going on this week…

Just kidding, we like it this way. And so do the customers I’ve been talking to.

Comments Off

Filed under Amazon, Application Mgmt, Cloud Computing, Conference, Everything, Linux, Manageability, Middleware, Open source, Oracle, Oracle Open World, OVM, Tech, Trade show, Utility computing, Virtualization, Xen

Are these your files? I found them on my cloud

Drip drip drip… Is this the sound of your cloud leaking?

It can happen in different ways. See for example this recent research paper, titled “Hey, You, Get Off of My Cloud: Exploring Information Leakage in Third-Party Compute Clouds”. It’s a nice read, especially if you find side channels interesting (I came up with one recently, in a different context).

In the first part of the paper, the authors show how to get your EC2 instance co-located (i.e. running in in the same hypervisor) with the instance you are targeting (the one you want to spy on). Once this is achieved, they describe side channel attacks to glean information from this situation.

This paper got me thinking. I noticed that it does not mention trying to go after disk blocks and memory. I don’t know if they didn’t try or they tried and were defeated.

For disk blocks (the most obvious attack vector), Amazon is no dummy and their “proprietary  disk  virtualization  layer  automatically  wipes every block of storage used by  the customer, and guarantees  that one customer’s data  is never exposed to another” as explained in the AWS Security Whitepaper. In fact, they are so confident of this that they don’t even bother forbidding block-based recovery attempts in the AWS customer agreement (they seem mostly concerned about attacks that are not specific to hypervisor environments, like port scanning or network-based DOS). I took this as an invitation to verify their claims, so I launched a few Linux/ext3 and Windows/NTFS instances, attached a couple of EBS volumes to them and ran off-the-shelf file recovery tools. Sure enough, nothing was found on  /dev/sda2 (the empty 150GB partition of local storage that comes with each instance) or on the EBS volumes. They are not bluffing.

On the other hand, there were plenty of recoverable files on /dev/sda1. Here is what a Foremost scan returned on two instances (both of them created from public Fedora AMIs).

The first one:

Finish: Tue Sep  1 05:04:52 2009

5640 FILES EXTRACTED

jpg:= 14
gif:= 670
htm:= 1183
exe:= 2
png:= 3771
------------------------------------------------------------------

And the second one:

Finish: Wed Sep  2 00:32:16 2009

17236 FILES EXTRACTED

jpg:= 236
gif:= 2313
rif:= 11
htm:= 4886
zip:= 182
exe:= 6
png:= 9594
pdf:= 8
------------------------------------------------------------------

These are blocks in the AMI itself, not blocks that were left on the volumes on which the AMI was installed. In other words, all instances built from the same AMI will provide the exact same recoverable files. The C: drive of the Windows instance also had some recoverable files. Not surprisingly they were Windows setup files.

I don’t see this as an AWS flaw. They do a great job providing cleanly wiped raw volumes and it’s the responsibility of the AMI creator not to snapshot recoverable blocks. I am just not sure that everyone out there who makes AMIs available is aware of this. My simple Foremost scans above only looked for the default file types known out of the box by Foremost. I suspect that if I added support for .pem files (used by AWS to store private keys) there may well be a few such files recoverable in some of the publicly accessible AMIs…

Again, kudos to Amazon, but I also wonder if this feature opens a possible DOS approach on AWS: it doesn’t cost me much to create a 1TB EBS volume and to destroy it seconds later. But for Amazon, that’s a lot of blocks to wipe. I wonder how many such instantaneous create/delete actions on large EBS volumes it would take to put a large chunk of AWS storage capacity in the “unavailable – pending wipe” state… That’s assuming that they proactively wipe all the physical blocks. If instead the wipe is virtual (their virtualization layer returns zero as the value for any free block, no matter what the physical value of the block) then this attack wouldn’t work. Or maybe they keep track of the blocks that were written and only wipe these.

Then there is the RAM. The AWS security paper tells us that the physical RAM is kept separated between instances (presumably they don’t use ballooning or the more ambitious Xen Transcendent Memory). But they don’t say anything about what happens when a new instance gets hold of the RAM of a terminated instance.

Amazon probably makes sure the RAM is reset, as the disk blocks are. But what about your private Cloud infrastructure? While the prospect of such Cloud leakage is most terrifying in a public cloud scenario (anyone could make use of it to go after you), in practice I suspect that these attack vectors are currently a lot more exploitable in the various “private clouds” out there. And that for many of these private clouds you don’t need to resort to the exotic side channels described in the “get off of my cloud” paper. Amazon has been around the block (no pun intended) a few times, but not all the private cloud frameworks out there have.

One possible conclusion is that you want to make sure that your cloud vendor does more than writing scripts to orchestrate invocations of the hypervisor APIs. They need to understand the storage, computing and networking infrastructure in details. There is a messy physical world under your clean shinny virtual world. They need to know how to think about security at the system level.

Another one is that this is a mostly an issue for hypervisor-based utility computing and a possible trump card for higher level of virtualization, e.g. PaaS. The attacks described in the paper (as well as block-based file recovery) would not work on Google App Engine. What does co-residency mean in a world where subsequent requests to the same application could hit any machine (though in practice it’s unlikely to be so random)? You don’t get “deployed” to the same host as your intended victim. At best you happen to have a few requests executed while a few requests of your target run on the same physical machine. It’s a lot harder to exploit. More importantly, the attack surface is much more restrained. No direct memory access, no low-level scheduler data, no filesystem… The OS to hardware interface that hypervisors emulate was meant to let the OS control the hardware. The GAE interface/SDK, on the other hand, was meant to give the application just enough capabilities to perform its task, in a way that is as removed from the hardware as possible. Of course there is still an underlying physical reality in the GAE case and there are sure to be some leaks there too. But the small attack surface makes them a lot harder to exploit.

[UPDATED 2009/9/8: Amazon just improved the ability to smoothly update your access certificates. So hopefully any such certificate found on recoverable blocks in an AMI will be out of data and unusable.]

[UPDATED 2009/9/24: Some good security practices that help protect you against block analysis and many other forms of attack.]

[UPDATED 2009/10/15: At Oracle Open World this week, I was assured by an Amazon AWS employee that the DOS scenario I describe in this post would not be a problem for them. But no technical detail as to why that is. Also, you get billed a minimum of one hour for each EBS volume you provision, so that attack would not be as cheap as I thought (unless you use a stolen credit card).]

4 Comments

Filed under Amazon, Cloud Computing, Everything, Google App Engine, Security, Utility computing, Virtualization, Xen

Oracle buys Virtual Iron

The rumor had some legs. Oracle announced today that is has acquired Virtual Iron for its virtualization management technology. This publicly-available white paper is a great description of the technology and product capabilities.

Here is a short overview (from here).

VI-Center provides the following capabilities:

  • Physical infrastructure: Physical hardware discovery, bare metal provisioning, configuration, control, and monitoring
  • Virtual Infrastructure: Virtual environment creation and hierarchy, visual status dashboards, access controls
  • Virtual Servers: Create, Manage, Stop, Start, Migrate, LiveMigrate
  • Policy-based Automation: LiveCapacity™, LiveRecovery™, LiveMaintenance, Rules Engine, Statistics, Event Monitor, Custom policies
  • Reports: Resource utilization, System events

Interesting footnote: I read that SAP Ventures was an investor in Virtual Iron…

I also notice that the word “cloud” does not appear once in the list of all press releases issued by Virtual Iron over three years. For a virtualization start-up, that’s a pretty impressive level of restrain and hype resistance.

1 Comment

Filed under Everything, IT Systems Mgmt, Manageability, Mgmt integration, Oracle, Virtualization, Xen

Announcing Xen Transcendent Memory project

If you have more than one child, you’ve probably heard yourself say things like “if you are not using your train, you should let your brother play with it” more often than you’d like. The same happens in a datacenter (minus the screams and tears, at least usually). In that context, the rivaling siblings take the form of guest virtual machines and the toys in contention are the physical resources of the host system: CPU, I/O, memory. While virtualization platforms do a pretty good job at efficiently sharing the first two, the situation is not nearly as good for memory. It is often, as a result, the limiting factor for virtualization-driven consolidation. A new project aims to fix this.

The Oracle engineers working on the Xen-based Oracle Virtual Machine have just announced a new open source (GPL-licensed) project to improve the sharing of physical memory between guest virtual machines on the same physical system. It’s called Transcendent Memory, or tmem for short.

Much more information, including a comparison with VMWare’s memory balloon, is available from the project home page.

Another reason to come to the upcoming Xen Summit (February 24 and 25), hosted by Oracle here at headquarters.

Comments Off

Filed under Everything, Linux, Open source, Oracle, OVM, Tech, Virtualization, Xen

OVF work in progress published

The DMTF has recently released a draft of the OVF specification. The organization’s newsletter says it’s “available (…) for a limited period as a Work In Progress” and the document itself says that it “expires September 30, 2008″. I am not sure what either means exactly, but I guess if my printed copy bursts into flames on October 1st then I’ll know.

From a very quick scan, there doesn’t seem to be a lot of changes. Implementers of the original specification are sitting pretty. The language seems to have been tightened. The original document made many of its points by example only, while the new one tries to more rigorously define rules, e.g. by using some version of the BNF metasyntax. Also, there is now an internationalization section, one of the typical signs that a specification is growing up.

The old and new documents occupy a similar number of pages, but that’s a bit misleading because the old one inlined the XSD and MOF files, while the new one omits them. Correcting for this, the specification has grown significantly but it seems that most of the added bulk comes from more precise descriptions of existing features rather than new features.

For what it’s worth, I reviewed the original OVF specification from an IT management perspective when it was first released.

For now, I’ll use the DMTF-advertised temporary nature of this document as a justification for not investing the time in doing a better review. If you know of one, please let me know and I’ll link to it.

[UPDATED 2008/10/14: It's now a preliminary standard, and here is a longer review.]

4 Comments

Filed under Everything, OVF, Specs, Standards, Virtualization, VMware, Xen, XenSource

OVF in action: Kensho

Simon Crosby recently wrote about an upcoming Citrix product (I think that’s what it is, since he doesn’t mention open source anywhere) called Kensho. The post is mostly a teaser (the Wikipedia link in his post will improve your knowledge of oriental philosophy but not your IT management expertise) but it makes interesting claims of virtualization infrastructure interoperability.

OVF gets a lot of credit in Simon’s story. But, unless things have changed a lot since the specification was submitted to DMTF, it is still a wrapper around proprietary virtual disk formats (as previously explained). That wrapper alone can provide a lot of value. But when Simon explains that Kensho can “create VMs from VMware, Hyper-V & XenServer in the OVF format” and when he talks about “OVF virtual appliances” it tends to create the impression that you can deploy any OVF-wrapped VM into any OVF-compliant virtualization platform. Which, AFAIK, is not the case.

For the purpose of a demo, you may be able to make this look like a detail by having a couple of equivalent images and picking one or the other depending on the target hypervisor. But from the perspective of the complete lifecycle management of your virtual machines, having a couple of “equivalent” images in different formats is a bit more than a detail.

All in all, this is an interesting announcement and I take it as a sign that things are progressing well with OVF at DMTF.

[UPDATED 2008/6/29: Chris Wolf (whose firm, the Burton Group, organized the Catalyst conference at which Simon Crosby introduced Kensho) has a nice write-up about what took place there. Plenty of OVF-love in his post too, and actually he gives higher marks to VMWare and Novell than Citrix on that front. Chris makes an interesting forecast: "Look for OVF to start its transition from a standardized metadata format for importing VM appliances to the industry standard format for VM runtime metadata. There's no technical reason why this cannot happen, so to me runtime metadata seems like OVF's next step in its logical evolution. So it's foreseeable that proprietary VM metadata file formats such as .vmc (Microsoft) and .vmx (VMware) could be replaced with a .ovf file". That would be very nice indeed.]

[2008/7/15: Citrix has hit the "PR" button on Kensho, so we get a couple of articles describing it in a bit more details: Infoworld and Sysmannews (slightly more detailed, including dangling the EC2 carrot).]

Comments Off

Filed under DMTF, Everything, IT Systems Mgmt, Manageability, Mgmt integration, OVF, Standards, Virtualization, Xen, XenSource

Book review: Xen Virtualization

Someone from Packt Publishing asked me if I was interested in reviewing the Xen Virtualization book by Prabhakar Chaganti that they recently published. I said yes and it was in my mailbox a few days letter.

The sub-title is “a fast and practical guide to supporting multiple operating systems with the Xen hypervisor” and it turns out that the operating word is “fast”. It’s a short book (approx 130 pages, many filled with screen captures and console output listings). It is best used as an introduction to Xen for people who understand computer administration (especially Linux) but are new to virtualization.

The book contains a brief overview of virtualization, followed by a description of the most common tasks:

  • the Xen install process (from binary and source) on Fedora core 6
  • creating virtual machines (using NetBSD plus three different flavors of Linux)
  • basic management of Xen using the xm command line or the XenMan and virt-manager tools
  • setting up simple networking
  • setting up simple storage
  • encrypting partitions used by virtual machines
  • simple migration of virtual machines (stopped and live)

For all of these tasks, what we get is a step by step process that corresponds to the simple case and does not cover any troubleshooting. It is likely that anyone who embarks on the task described will need options that are not covered in the book. That’s why I write that it is an introduction that shows the kind of thing you need to do, rather than a reference that will give you the information you need in your deployment. You’ll probably need to read additional documentation, but the book will give you an idea of what stage you are in the process and what comes next.

Even with this limited scope, it is pretty light on explanations. It’s mostly a set of commands followed by a display of the result. Since it’s closer to my background I’ll take the “managing Xen” chapter as an example. There is nothing more basic to management than understanding the state of a resource. The book shows how to retrieve it (“xm list”) and very briefly describes the different states (“running”, “blocked”, “paused”, “shutdown”, “crashed”) but you would expect a bit more precision and details. For example, “blocked” is supposed to correspond to “waiting for an external event” but what does “external” mean? Sure the machine could be waiting on I/O, but it could also be on a timer (e.g. “sleep(1000)”) or simply have run out of things to do. I don’t think of a cron job as an “external event”. Also, when running “xm list” you should expect to always see dom0 in the “running” state (since dom0 is busy running your xm command) and on a one-core single-CPU machine (as is the case in the book) that means that none of the other domains can be in that state. That’s the kind of clarification (obvious in retrospect) that goes one step beyond the basic command description and saves some head scratching but the book doesn’t really go there. As another example, We are told in the “encryption” section that LUKS helps prevent “low entropy-attacks” but if you’re the kind of person who already knows what that means you probably don’t have much to learn from the “encryption” chapter of the book. In case you care, it is a class of attacks that take advantage of poor sources of random numbers and you can read all the details of how entropy is defined in this classic 1948 paper (it doesn’t have much to do with how the term is defined in physics).

Among the many more advanced topics that are not covered I can think of: advanced networking, clustering, advanced storage, Windows guests (even though it’s not Xen’s strong point), migration between physical and virtual, relationship to other IT management tasks (e.g. server and OS management), performance aspects, partitioning I/O so domains play well together, security considerations (beyond simply encrypting the file system), new challenges introduced by virtualization…

Xen documentation on the web is pretty poor at this point and the book provides more than most simple “how-to” guides on installing/configuring Xen that you can Google for. And it brings a consistent sequence of such “how-to” guides together in one package. If that’s worth it to you then get the book. But don’t expect this to cover all your documentation needs for anything beyond the simplest (and luckiest) deployment. I would be pleased to see the book on the desk of an IT manager in a shop that is considering using virtualization, I would be scared to see it on the desk of an IT administrator in a shop that is actually using Xen.

[UPDATED on 2008/02/01: Dan Magenheimer, a Xen expert who works on the Oracle VM, highly recommends another Xen book that just came out: Professional Xen Virtualization by William von Hagen. I haven't seen that book but I trust Dan on this topic.]

Comments Off

Filed under Book review, Everything, Virtualization, Xen