Foreword to the First Edition
I’m no longer sure when I first became hooked. Was it when I overheard a casual conversation about running a “test” copy of MVS in parallel with the real copy of MVS on a new 390 mainframe? Or was it the idea of Zarniwoop researching the Hitchhiker’s Guide to the Galaxy in an electronically synthesized copy of the entire universe he kept in his office? Whatever the cause, I’m still addicted to virtual machine technology.
Fooling a whole stack of software to run correctly on a software simulation of the platform it was designed to run on has been a recurring interest in my career. Poring through the history of VM/370 as a graduate student, absorbing James Gosling’s audacious idea of the Java VM, spending a few weeks building an experimental machine emulator to run SPARC applications on Solaris for PowerPC, the “aha!” moment when we realized how useful it would be if we arranged that a set of processes could behave as a little OS within an OS (the idea that became Solaris Zones), the first bring-up of OpenSolaris running as a paravirtualized guest on Xen—those are just a few of the highlights for me.
This book began as a project within Sun in mid-2009 during Oracle’s acquisition of the company, so it both explores aspects of Sun’s virtualization technology portfolio, and—now that the acquisition is complete—peers a little into 2010. Sun’s unique position as a systems company allowed it to deliver a full set of integrated virtualization technologies. These solutions span the different trade-offs between maximizing utilization for efficiency and maximizing isolation for availability, while enabling the system to be managed at a large scale and up and down the layers of the systems architecture. Because that systems perspective informs everything we do, we have a wealth of solutions to match the diverse needs of modern enterprise architectures. Many of these tools are interoperable, enabling solutions that are otherwise impossible or impractical. Oracle’s acquisition of Sun provides two further benefits to that portfolio: a secure future for these technologies and the exciting potential for integration with Oracle VM, Oracle Enterprise Manager, and the wealth of Oracle applications.
Here are some examples from the Sun portfolio. ZFS is a key storage virtualization technology at the core of the future of the Solaris operating system as well as the appliance products we build from Solaris technology today. Solaris networking virtualization technologies allow cutting-edge network hardware to be exploited and managed efficiently while providing a natural virtual network interface abstraction. For server virtualization, Solaris Zones (also known as Solaris Containers) have turned out to be very popular and very successful—a natural fit for the needs of many customers. The logical domains hypervisor is an extremely efficient design, and enables customers to get the most out of the tremendous throughput capability of SPARC CMT platforms. Our work with the Xen community enables a high-performance Solaris x64 guest for Oracle VM. For client virtualization, look no further than VirtualBox—for the laptop and desktop, both as a developer utility, and as a virtual appliance developer tool for the cloud. And it’s not just a client technology: VirtualBox is the server component of Sun’s virtual desktop infrastructure product, and it continues to grow more server-class features with every release. As well as infrastructure virtualization platforms, we have created infrastructure management software—Ops Center—intended to reduce the complexity that comes with using the new capabilities in large-scale deployments.
Virtual machines in one form or another have been around for a long time. Yet virtualization is such a fundamental idea that it remains associated with many developing fields. In the past decade, the runaway success of hypervisor-based virtualization on x64 platforms has largely been driven by the operational savings achieved by consolidating Microsoft Windows guests. But now this layer of the system architecture is just part of the way infrastructure is done—a new raft of capabilities can be built on top of it.
Recently we’ve seen the emergence of the Infrastructure as a Service (IaaS) style of cloud computing. Enabled by the combination of ever-increasing Internet connectivity and bandwidth, coupled with Moore’s law about providing more and more computational power per dollar, users of an IaaS service send their entire software stacks to remote data centers. Virtualization decouples the software from the hardware to enable those data centers to be operated almost as a utility. This approach promises to revolutionize the fundamental economics across the IT industry. The capital expenditures currently devoted to under-utilized equipment can be shifted to pay-as-you-go operating expenses, both within large enterprises and between service providers and their customers.
This new layer of the systems architecture brings new opportunities and new problems to solve—in terms of security, observability, performance, networking, utilization, power management, migration, scheduling, manageability, and so on. While both industry and the academic research community are busily responding to many of those challenges, much remains to be done. The fundamentals remain important, and will continue to differentiate the various virtualization solutions in the marketplace.
This book is a deep exploration of virtualization products and technologies provided by or for Solaris, written by experienced practitioners in the art of delivering real solutions to data center problems. It provides a holistic view of virtualization, encompassing all of the different models used in the industry. That breadth itself is rare: No other organization has as complete a view of the entire range of system virtualization possibilities. A comprehensive background chapter leads neophytes into virtualization. Experienced data center architects will appreciate the individual chapters explaining the technologies and suggesting ways to use them to solve real problems—a critical resource in a rapidly changing world. I hope you find it as fascinating as I do!
Tim Marsland
Vice President and Fellow, Sun Microsystems, Inc.
Menlo Park