CHAPTER

2

What Is Oracle VM?

Oracle VM is no longer considered new to the VM marketplace, and the underlying Xen technology has been thoroughly tested and used. Oracle introduced Oracle VM at the Oracle World conference in 2007 and made the product available for download shortly after that. At the time, Oracle touted this as being one of its largest software announcements in the history of the company. The Oracle VM product consists of two major components: the Oracle VM Server and the Oracle VM Manager.

Since Oracle’s acquisition of Sun Microsystems, the Oracle VM product, which is the subject of this book, was rebranded as Oracle VM Server for x86. At the same time, the virtualization products that were available for the Sun hardware product line were rebranded as Oracle VM Server for SPARC. In addition, Oracle has added desktop virtualization to its product line with Oracle VM VirtualBox. In this book, Oracle VM Server for x86 will be referred to simply as Oracle VM. Any of the other products will be referred to by their full name.

In this chapter, you will learn about the history of Oracle VM and Xen, its underlying technology, as well as some of the competition. This chapter also covers some of the key features of Oracle VM and the Oracle VM template library.

History of Oracle VM and Virtualization

Oracle VM was not the first virtualization product on the market, nor is it the last. VMware was introduced in 1998 and is majority owned by EMC. VMware introduced its first virtualization product for the desktop in 1999 and its first server product in 2001. Then, in 2003, VMware introduced the VMware Virtual Center, the vMotion, and Virtual SMP technology. These products made virtualization viable for server consolidation in the enterprise. Prior to that, VMware was primarily used only as a test or training platform. In 2004, VMware introduced 64-bit support. EMC also acquired VMware in 2004.

As with Oracle VM, VMware is supported on the Intel/AMD x86 platforms only. This, in part, has led to the race between Intel and AMD to focus their efforts on providing an extensive set of features that optimize virtualization on their platforms. With both Oracle VM and VMware, fully virtualized systems are now supported. In addition, Oracle VM supports paravirtualization, where the underlying operating system realizes that it is running on a virtual system and makes intelligent choices based on that knowledge. Although VMware provides replacement drivers for video and I/O, it isn’t the same as paravirtualization. However, both products also support any OS that will run on the x86 platform in a fully virtualized guest.

The third major player in the virtualization market is Microsoft with its Hyper-V product. The Microsoft Hyper-V virtualization solution is a hypervisor-based virtualization product that was introduced in 2008. This product appears to be targeted primarily to the Microsoft Windows environment.

Another player in the virtualization market is KVM (Kernel Virtual Machine). The built-in virtualization for Linux has moved from Xen to KVM. Although Oracle maintains open-source compatibility with KVM, they have decided to stick with Xen as the basis of Oracle VM rather than moving to KVM. For the time being, Oracle is continuing to use Xen as its preferred virtualization technology.

One additional player in the virtualization market is Citrix. Citrix had purchased XenSource, but isn’t pushing it as a dominant virtualization platform, as Citrix tends to focus more on the desktop replacement rather than the virtualization environment. Citrix continues to be a major player in the desktop virtualization market but does not participate in server virtualization.

In addition to the major commercial virtualization products, other virtualization products have been created specifically for cloud providers such as the Amazon AWS (Amazon WorkSpaces), which is developed and maintained by Amazon. Other commercial vendors have done the same. Oracle Cloud services are run on Oracle VM or a slightly modified version of Oracle VM.

These companies do not represent the entirety of the virtualization market and virtualization products, but they do represent Oracle VM’s main competition. The focus of this book is Oracle VM; although many other virtualization products are available, including hardware virtualization products, they will not be covered here.

Virtualization technology is not new to Oracle. Oracle VM is based on the Xen Hypervisor, which is a proven and stable technology. To understand the history of Oracle VM, you must first look at the history of the Xen Hypervisor.

History of Xen

The Xen virtualization product began around the same time as VMware. It was created at the University of Cambridge Computer Laboratory, and its first version was released in 2003. The leader of the project then went on to found XenSource. Unlike both VMware and Hyper-V, Xen is maintained by the open-source community under the GNU General Public License. In 2007, XenSource was acquired by Citrix Systems.

Whereas VMware and Hyper-V only support the x86 architecture, Xen supports x86, x86_64, Itanium, and PowerPC architectures. As mentioned in Chapter 1, the Xen architecture is based on a hypervisor. This hypervisor originally allowed only Linux, NetBSD, and Solaris operating systems to operate in a paravirtualized environment. However, since the introduction of Xen 3.0 and hardware virtualization support in hardware, unmodified OSs can now operate in Xen.

Oracle VM 3.4 is based on the Xen 4.4 kernel. In order to fully appreciate where the Xen 4.4 kernel is, let’s look at a brief history of the Xen Hypervisor. The following is a brief timeline of Xen’s history:

Let’s look at a few of the major releases in more detail. Because Xen is the basis for Oracle VM, understanding where it is coming from and how the various releases have evolved is important.

Xen 1.x

Xen 1.0 was the first release of the Xen product and included all of the basic pieces needed to support virtualization. Xen 1.0 supported only the Linux operating system, but at the time of its release, the Xen development team was already working to enable Microsoft Windows to run in a virtual environment. The original release of Xen was based on paravirtualization, where the guest operating system is modified so that it’s aware it is actually running in a virtualized environment. This awareness improved performance but did not allow the full range of OSs to run unmodified in a virtualized environment. Xen 1.0 reached its goal of allowing any application that ran on the guest OS to be able to run in an unmodified manner, however.

Microsoft Windows was the first non-Linux operating system ported to Xen, but Microsoft pulled support shortly after announcing its support to begin work on its own virtualization technologies.

Xen 2.x

The Xen 2.0 release again targeted the x86 market and included a number of substantial new features. The most impressive of these new features gave users the ability to perform a “live migration” of a virtual guest from one host to another with no interruption in service. This feature is known as vMotion in VMware and is one of the truly outstanding features of virtualization. Using this feature, users could adjust and manage the load on the underlying hosts without interrupting service to the guest OS. In addition, XenSource improved the manner in which virtual I/O devices were used and configured, especially in the area of networking.

Xen 3.x

Even though Xen 2.0 and, in some respects, 1.0 had significant features, it wasn’t until Xen 3.0 that Xen was truly ready for the enterprise. The features enabled in this version made Xen viable as an alternative to physical servers and increased its popularity. These features have created the explosion in the virtualization market. In the past few years, the popularity and variety of virtualization have grown tremendously.

In this section, we cover the history of Xen 3.x in more detail.

Xen 3.0    Xen 3.0 included many features that were required for enterprise computing, including the following:

   32P support    Xen 3.0 added support for up to 32-way SMP guest operating systems. This support was important for larger applications such as databases.

   64-bit    Xen 3.0 provided 64-bit support for the x86_64 platform, including Intel and AMD processors.

   PAE    Xen 3.0 added support for the Intel Physical Addressing Extensions (PAE) to support 32-bit servers with more than 4GB physical memory. Although this was not as efficient as 64-bit support, it was better than nothing.

   Fully virtualized    When using Intel VT-x (or AMD’s AMD-V), Xen 3.0 made it possible to run unmodified guest operating systems as hardware virtual machines (HVMs). This feature is sometimes known as hardware-assisted virtualization. It allowed for OSs such as Microsoft Windows and earlier releases of Linux and UNIX to run as unmodified guests.

   Miscellaneous enhancements    Xen 3.0 added other enhancements, including improved utilities, graphics, and Advanced Configuration and Power Interface (ACPI) support.

Without 64-bit support, many people found it difficult to migrate their applications to a virtualized environment. This is probably the most significant improvement in the Xen 3.x family.

Xen 3.1    The Xen 3.1 release, although not as significant as the 3.0 release, added many valuable new features:

   XenAPI support    Xen 3.1 added support for XenAPI 1.0. This API uses XML configuration files for virtual machines as well as VM lifecycle management operations.

   Save/restore/migrate    Xen 3.1 added the preliminary save/restore/migrate support for HVMs.

   Dynamic memory    Xen 3.1 introduced dynamic memory control for nonparavirtualized machines.

   32-bit on 64-bit    Xen 3.1 added support for a 32-bit OS (including PAE) to run on a 64-bit host.

   Raw partitions    Xen 3.1 added support for virtual disks on raw partitions.

Xen 3.2    Like the 3.1 release, Xen 3.2 was not as significant as the 3.0 release, but it added many valuable new features:

   XSM    Xen 3.2 added Xen Security Modules (XSM) support.

   Suspend    Xen 3.2 added ACPI S3 suspend-to-RAM support for the host system.

   PCI passthrough    Xen 3.2 added the first preliminary release of PCI passthrough support (assuming supported hardware).

   Bootloader    Xen 3.2 added a preliminary release for a wider range of bootloaders in fully virtualized (HVM) guests, using a full emulation of x86 “real mode.”

   Faster graphics    Xen 3.2 included faster standard (nonsuper) VGA modes for HVM guests.

   Timers    Xen 3.2 added support for configurable timer modes for HVM guests.

Xen 3.3    Like the 3.1 and 3.2 releases, the Xen 3.3 release was not as significant as the 3.0 release, but it probably had the most new features of any of the minor releases:

   Power management    Xen 3.3 added power management for P- and C-states to the hypervisor. In CPU terms, P-states are operational states and C-states are idle states.

   PVGrub    Xen 3.3 added support for booting the PV (paravirtualized) kernels using the actual grub inside the PV domain instead of the host grub.

   PV performance    Xen 3.3 improved paravirtualized performance by removing the domain lock from the pagetable-update paths.

   Shadow3 Xen 3.3 optimized the shadow pagetable algorithm to improve performance.

   Hardware assist    Xen 3.3 added hardware-assisted paging enhancements, including 2MB page support to improve large memory performance.

   PVSCSI drivers    Xen 3.3 allowed for SCSI access directly into the PV guests rather than through a translation layer through PVSCSI drivers.

   Device passthrough    Xen 3.3 added miscellaneous driver enhancements to allow device passthrough rather than through a translation layer, including multiqueue support on NICs.

   Full x86    Xen 3.3 added full x86 real-mode emulation for HVM guests on Intel VT, allowing for a wider range of legacy guest OSs.

Xen 3.4    Xen 3.4 was the release used by Oracle in Oracle VM 2.2. The Xen 3.4 release did not introduce any major new features but did improve many existing features:

   Device passthrough    Xen 3.4 added more enhancements started in the Xen 3.3 release.

   Offlining    Xen 3.4 added support for CPU and memory offlining, where unused CPUs and memory can be “turned off” to save resources.

   Power management    Xen 3.4 enhanced the power management features introduced in Xen 3.3, including scheduler and timers optimized for peak power savings.

   Hyper-V    Xen 3.4 added support for the Viridian (Hyper-V) enlightenment interface.

Xen 4.x

As with the other major releases of Xen, the Xen 4.0 had a number of significant and minor features. These features increased the ability of Oracle VM to be an enterprise virtualization platform. The evolution of Xen has increased its ability to participate in the virtualization market as well.

This section covers the history of Xen 4.x in more detail.

Xen 4.0    Xen 4.0 added upgrades and features that create a more robust and improved platform. Xen 4.0 included many features that were required for enterprise computing, including the following:

   Performance and scalability    Xen 4.0 added support for 128 CPUs and 1TB of RAM on a physical server. It also added support for up to 128 vCPUs and 512GB of RAM per guest operating system. This support was important for larger applications such as databases.

   Hardware support    Xen 4.0 provided support for improved IOMMU PCI passthrough using hardware-accelerated I/O virtualization techniques for Intel VT-d and AMD IOMMU.

   Online operations    Xen 4.0 provided support for online resizing of guest disks without reboot/shutdown.

   Hot-plug    Xen 4.0 provided RAS (Reliability, Availability, and Serviceability) features such as hot-plug CPU and memory.

Xen 4.1    Xen 4.1 added upgrades and features that create a more robust and improved platform. Xen 4.1 is not as significant as Xen 4.0, but is still important. Its features include the following:

   CPU pools    Xen 4.1 added support for CPU pools to allow for hard partitioning. This is very significant for Oracle database licensing.

   AVX    Xen 4.1 provided support for x86 Advanced Vector eXtension (AVX), which allows for more complex CPU instructions.

   Jumbo frames    Support for jumbo frames was fixed in Xen 4.1.

Xen 4.2    Xen 4.2 added some scalability and performance improvements:

   Performance and scalability    Xen 4.2 added support for 4095 CPUs and 5TB of RAM on physical servers. It also added support for up to 128 vCPUs and 512GB of RAM per PV guests operating systems, and 256 vCPUs and 1TB of RAM for HVM guests. This support was important for larger applications such as databases.

Xen 4.3    Xen 4.3 added some new features, including an experimental feature:

   Experimental support for ARM Virtualization    Xen 4.3 added development support for ARM processors; however, no production usage was supported because hardware for ARM processors was not available.

   NUMA-aware scheduling    Xen 4.3 allowed the Xen scheduler to prefer a CPU that a process was previously run on, so the VM would at least try to run on the CPU where its memory resided.

   Support for openvswitch    Openvswitch is a new networking bridging mechanism.

Xen 4.4    Xen 4.4 has added several new features aimed at improving performance and scalability:

   Solid libvirt support for libxl    Xen 4.4 has improved the interface between libvirt and libx.

   Improved Xen event channel Xen 4.4 has added support for a scalable event channel interface.

   Hypervisor ABI for ARM support    Xen 4.4 has improved the hypervisor ABI for ARM support, but it is still not available for production.

   Nested virtualization    Xen 4.4 has improved nested virtualization so it is now ready for tech review and will soon be available in production.

This history of the Xen virtualization monitor shows the dynamic nature of virtualization technology and the care taken to provide the latest and greatest features possible. In addition to the features provided by Xen, Oracle has added a management console designed to assist with the use and management of Xen and Oracle VM. The next section describes the additional features provided by Oracle.

Oracle VM Features

Oracle VM is based on the Xen Hypervisor, but there is more to Oracle VM than just the server software itself. Oracle has taken the Xen Hypervisor and added enhancements and fixes as well as improved the management of the virtualized environment. Oracle VM is made up of two components: the Oracle VM Server and the Oracle VM Manager.

Oracle VM Server

The Oracle VM Server has been enhanced to provide better manageability, scalability, and supportability. In addition to modifying the Xen Hypervisor for their own product, Oracle’s engineering team contributes to the development of the mainstream Xen software.

Oracle VM Server Features

The Oracle VM Server is the application that actually manages and runs the virtual guests. The Oracle VM Server, which is installed on a bare-metal system, consists of the Xen Hypervisor, a dom0 guest that is used for management and monitoring, and includes the Oracle Virtual Server (OVS) agent that runs within dom0. As you will see throughout this book, the Oracle VM Manager is what really makes much of Oracle VM work. Features of the Oracle VM Server include the following:

   High availability    You can configure resources to restart guests on another host if the underlying host fails.

   Live migration    You can relocate guests from one host to another with no loss of service. This feature is great for load balancing as well as system maintenance. Oracle VM is the only virtualization technology that performs live migration using an encrypted connection, thus providing an additional layer of security.

   Distributed Power Management    The Distributed Power Management system allows VMs to be automatically migrated off of lightly used servers so that they can be powered off during light load times.

   Distributed Resource Scheduler    This allows VMs to be migrated in order to allow for busy servers to offload VMs to servers with more resources available.

   Load balancing    If configured, Oracle VM automatically load balances upon guest startup, thus providing the best overall performance to the VM farm by maximizing resource utilization.

   Performance    Oracle VM is optimized for performance, and the Xen Hypervisor is among the fastest forms of virtualization.

   Rapid provisioning    Through the use of cloning and virtual machine templates, Oracle VM can quickly and efficiently create new guest systems.

   VM templates    Oracle provides a wide range of preconfigured virtual machine templates that can take the guesswork out of configuration. These templates are available from Oracle.com. You can customize downloaded templates, and you can also create completely custom templates based on an Oracle VM guest you create on your own.

   Fault tolerance    Oracle provides a number of features to offer high availability and disaster recovery to both the host servers and the virtual machines. These features are covered in detail in this book.

These features and more are covered in detail throughout the remainder of this book. In the next chapter, the Oracle VM/Xen architecture is covered in detail.

VM Guest Support

Oracle VM 3.x supports a full range of guest operating systems using hardware virtualization, as listed in Table 2-1. Using paravirtualized drivers will improve the performance of the system by avoiding the execution of unnecessary code.

TABLE 2-1.    Supported Linux and UNIX OSs Using Hardware Virtualization

Oracle VM 3.x also supports a full range of guest operating systems using paravirtualization, as listed in Table 2-2.

TABLE 2-2.    Supported Linux and UNIX OSs Using Paravirtualization

TABLE 2-3.    Supported Windows OSs Using Paravirtualized Drivers

Host Hardware Requirements

In order for Oracle VM to run effectively, there are some minimum requirements on the class of machine; however, most modern systems will work. Here are the requirements:

   Host platforms    Oracle VM currently supports Intel and AMD x86 and x86_64 platforms. The minimum CPU is the i686; however, to run HVM fully virtualized guests, you must use CPUs with virtualization acceleration. Intel CPUs indicate virtualization acceleration with the “vmx” flag and the AMD processors with the “svm” flag.

   Memory    The amount of memory should be proportional to the size and number of VMs. Currently, Oracle VM Server supports a maximum of 6TB of RAM. Of this 6TB of RAM, you can allocate 500GB to a PVM 64-bit guest, 1TB to an HVM 64-bit guest, 2TB to a PVHVM guest, and 64GB of RAM to a 32-bit guest.

   CPUs    As mentioned previously, having CPUs that support virtualization is advantageous. A minimum of one CPU is required, but this number is not suitable for more than one or two guests. A maximum of 384 CPUs is currently supported. The best practice is to reserve one core for dom0 and use the remaining cores/processors for the domU virtual machines.

   Disk support    Oracle VM currently supports SCSI, SAS, IDE/SATA, NAS, iSCSI, FC, and limited support for Fibre Channel over Ethernet (FCoE) storage.

Chapter 4 contains more detailed information on how to properly determine the number of CPUs and the amount of memory needed for particular applications.

Oracle VM Manager

A major feature of Oracle VM is the management console, which is called the Oracle VM Manager. The Oracle VM Manager is a web-based application that you use to monitor and configure the entire VM farm. You install and configure the Oracle VM Manager on a Linux system. This Linux host can be a standalone server or a virtual machine; however, if you choose to install the Oracle VM Manager on an Oracle VM guest, you will have to manage that VM manually. That is, you cannot start the guest via the console because it is hosting the console. Of course, the VM where Oracle VM Manager is installed can be managed by another Oracle VM server pool or even a VMware or KVM guest.

You can download the standalone Oracle VM Manager from the same location as the Oracle VM Server (www.oracle.com). Since release 5, Oracle VM Manager has also been incorporated into Oracle Enterprise Manager (OEM) Grid Control with the Oracle VM Management Pack. OEM Grid Control with the VM Management Pack allows for centralized management and monitoring of hosts, databases, applications, and virtual machines. You can see an example of the standalone Oracle VM Manager in Figure 2-1. The VM Manager console is where you perform operations such as creating, starting, stopping, live migrating, and deleting Oracle VM guests.

FIGURE 2-1.    Oracle VM Manager

In addition to the Oracle VM Manager, command-line utilities are available. These command-line utilities let you script and easily modify and save operations. Later in this book, we cover the standalone Oracle VM Manager (Chapter 10), the command-line utilities (Chapter 11), and Cloud Control (Chapters 23, 24, and 25) in detail.

Oracle Support for VM

Currently, Oracle VM is available free of charge. Oracle derives its revenue from selling subscriptions for Linux support, which includes Oracle VM as well as other Oracle open-source products. You’ll find both advantages and disadvantages to going the “single vendor” route with software deployments. By deploying Oracle VM, Oracle Enterprise Linux (OEL), and Oracle applications and purchasing Oracle support, you only have one place to go in the event of a failure. The disadvantage is lack of selection.

On the other hand, Oracle support is still available if you use Red Hat Enterprise Linux. If you purchase Oracle support for Red Hat Enterprise Linux, your updates will come from Oracle’s servers, not Red Hat’s. After running the up2date utility on the Red Hat server, you’ll see no differences between the Red Hat installation and an OEL installation. Oracle keeps OEL in lock-step with Red Hat at all times.

As with all Oracle products, Oracle stands behind its software. In addition, to assist customers rapidly, Oracle offers Advance Customer Services. These services include assessment and planning services, deployment, and ongoing support and/or monitoring if you desire. The level of support you get is based on your individual needs.

Oracle is committed to ongoing virtualization support and to supporting the open-source community in this area. After all, with virtualization comes a whole range of advantages, including power and cooling reduction, centralized management, and optimized provisioning. All these advantages are covered in this book.

Oracle’s VM Template Library

One of the most exciting advantages of Oracle VM is the extensive Template Library. Oracle not only supplies the VM system, but also the operating system, database software, applications, and so on, as well as preconfigured templates. These templates allow you to deploy applications rapidly because part of the work has already been done for you. The Oracle VM Template Library is available at Oracle.com in the software download section.

Oracle’s preconfigured templates are easy to deploy and configure. Each template is designed for a specific application stack and, as such, has been tested and validated. Thus, these templates make downloading, deploying, and running applications easy.

After you’ve downloaded the templates from the Oracle website, you can easily import them into the Oracle VM Manager. Once these templates are imported into the Oracle VM Manager, you can configure new guests from them. We’ll cover how to create guest systems from templates in Chapter 18. Once you have created the virtual machine, it is just a matter of configuring and deploying the guest.

The Oracle Template Library is divided into 64-bit and 32-bit templates. You might find it a little surprising, but a lot of software still has not been ported to 64-bit Linux. This includes some Oracle products as well. This section provides a brief overview of the 32-bit and 64-bit templates that are currently available at the writing of this book.

Most of the VM templates provided by Oracle are “Just enough OS” (JeOS) installations, based on the Oracle standard of installing just the components needed to perform the task at hand. This not only provides for an efficient OS deployment but also helps to meet security standards as well.

Oracle 64-bit VM Templates

The Oracle VM 32-bit templates are only available in archives and are not readily available for download any longer. All templates are now 64-bit.

The following 64-bit Oracle VM templates are available from http://www.oracle.com/technetwork/server-storage/vm/templates. The number of templates is always increasing, and there are too many to list. Therefore, only a sample of the categories and templates are listed here:

   Oracle Enterprise Manager 12c and 13c

   Oracle VM Manager

   Oracle VM Template Builder

   Oracle VM Server

   Sun Ray Software

   Oracle Secure Global Desktop

   Oracle VM Templates for Exalogic

   E-Business Suite (multiple versions)

   E-Business Suite for Oracle Exalogic (multiple versions)

   JD Edwards and Tools (multiple versions)

   Oracle Peoplesoft

   Oracle Business Intelligence Enterprise Edition

   Oracle Application Server

   Oracle Fusion Middleware

   Oracle Database 12c and 11g both Stand-Alone and RAC

   MySQL Enterprise Edition

   Oracle Linux (multiple versions)

   Oracle Solaris (multiple versions)

   Brocade Virtual Traffic Manager

Many 64-bit templates are available currently, and more are being added.

Oracle has provided an extensive set of preconfigured templates. These templates are built using the JeOS (Just enough OS) Linux software and configuration scripts necessary to deploy the system and the application. Specifics on how to use many of these templates and how to use templates in general are provided in Chapter 18.

Summary

This chapter continued our introduction to virtualization, and Oracle VM in particular. The chapter began by explaining more about what Oracle VM is. You cannot understand what Oracle VM is without also understanding what Xen and the Xen Hypervisor are. This chapter gave a brief introduction into those concepts and also touched on Oracle’s support for virtualization and the open-source manner in which Xen is developed and supported.

The chapter concluded with an overview of the Oracle Template Library. This template library provides a way to download and deploy a complete virtualization environment quickly and easily. These templates are built using the Oracle JeOS Linux distribution. In addition, most of the templates include preinstalled applications that are ready to be configured and deployed. Of course, these templates might need customizing, which will be covered in Chapter 17.

The next chapter explores the Oracle VM architecture, including not only the architecture of the VM Server and VM Manager but the Xen Hypervisor architecture as well. By understanding how Xen and Oracle VM work, you will better understand how to configure and tune them.