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Oracle VM Manager 2.1.2

Chapter 1. Introduction to Oracle VM

As stated in the Preface, Oracle VM Manager is a management product developed by Oracle that complements the Oracle Grid Control. Oracle VM Manager is increasingly popular within the Oracle community. In addition, firms that weren't Oracle customers are now adopting it, due to its low cost high-end support. This is clearly good news for Oracle as it really needs to find its place in this new and emerging market.

At the time of writing this book, Oracle has joined the Xen.org advisory board, thus joining the companies IBM, HP, Sun, and others who understand the need of Open Source hypervisors in this increasingly commoditizing market. This is great news as Oracle's VM is derived from the Open Source project Xen. This is a very important development for the Open Source Virtualization revolution and Oracle is poised to benefit from it tremendously.

In this chapter we will be covering the following topics:

Virtualization: A general introduction
Oracle VM components: This will comprise of Oracle VM Manager, Oracle VM Server, and Oracle VM Agent
Xen hypervisor: Domains, VMs, and much more.

Virtualization: What is it?

I have assumed that you know what virtualization is and now want to explore Oracle's version of virtualization. Still we feel that a quick introduction and a brief history of virtualization can never hurt. It is very hard to compact the past 50 years of IT achievements about virtualization, but I will attempt to cover it (very) briefly.

Brief history of virtualization

To take a look at x86 virtualization—a concept that often confuses a lot of IT Managers (even today) when they are confronted by consultants, vendors, or even internal staff, we have to go back to the 60's when IBM first introduced "Time sharing". Time sharing is basically sharing resources of expensive machines among several users, something we also call multi-tasking. Back then the machines were so expensive that it was necessary to come up with something creative. Fast forwarding 50 years we have come a full circle with the re-introduction of virtualization—only this time it has come to dominate the x86 servers. This was done, or should we say initiated, by VMware, which went on to create this huge ecosystem around it. Then came Xen, an Open Source project that began its subtle penetration into the ASP space and hosting providers, and which was later to be acquired by Citrix. Microsoft, not to be left behind in the process, carried on to acquire Connectrix, and after conducting several rebranding exercises on its hypervisor, later introduced Hyper-V.

Oracle worked on Xen's Open Source technology and introduced its Xen-flavored virtualization software as well. The list is quite exhaustive as the virtualization market has become rather huge. You might even say that in the drive to battle the oversubscription monster, the mushroom effect of all of the start-ups has created the over-subscription dilemma for themselves.

The introduction of virtualization is definitely the most significant event in the history of IT. It can drive down the costs dramatically and provides several open and public platforms to general public in the form of "public clouds". VMware, Microsoft, and several other firms are constantly fighting for the "private cloud" space where the mother-of-all virtualization, IBM, is also fighting. There has been a huge data center build-up across the world where all IT firms are battling to spread their wings and go after the Cloud Computing space.

Virtualization: What is it?

Brief history of virtualization

What forms of virtualization do we have?

There are several forms of virtualization and let's briefly go through a few of them (for the sake of brevity we will stick to server virtualization):

Emulation: A trick to copy a resource and make it look like some other resource can be called emulation.
Partitioning: Segmenting a resource so it looks like many resources.
Clustering: Aggregating many resources so they look like one. Think of the Oracle RAC VIP, where all you need is one IP which is a Virtual IP.

However exciting it sounds, we won't go too deep into the partitioning and clustering part and instead we'll have a look at the forms of emulation. They are—full virtualization, para-virtualization, and hardware-assist virtualization.

Full virtualization uses a concept of Binary Translation (BT) to provide a typical runtime re-write method which is required for this method to work. Here each instruction is read from the machine's binary and helps place the machine in a similar state to where the VM would be, after it has carried out that specific function. However, there are discussions about the "accuracy of emulation" as to how accurate the instruction modifications are. There are five types of accuracies, from datapath accuracy to HLE. But we won't delve into these deeper as we might have to get scientists from Intel and AMD to do the explanation.

Para-virtualization took birth from the Xen project originated at Cambridge University. It is the Open Source answer to the ring privileging solution. Simply said, instead of capturing the whole IA32 instruction set, it just captures the parts that are altered, thus increasing the performance of the VMs against the full-virtualization methods.

Finally, hardware-assist virtualization rests on the newer families of chips such as Intel VTx and AMD V chipsets. This enables unmodified VMs to execute on more enhanced VMMs (Virtual Machine Monitors). They might be faster than the above mentioned two methods but a lot of mixing occurs where both full and para-virtualization solutions are taking full advantage of the VTx and AMD V technologies.

Oracle VM Manager configuration

In this section, we will see some of the configuration possibilities of Oracle VM Manager. The deployment of Oracle VM can be done in several ways. The server pools within Oracle VM platform is the best way to go about when setting up the Oracle VM farm. The following diagram will make it a bit easier to understand how the pools are built:

Let's take a closer look at the various components that play a key role in defining what type of Oracle Cloud farm we can build with Oracle's VM platform:

Oracle VM Manager Host: This machine will typically have Oracle's VM Manager installed. This is the place for us to be in order to carry out all of the administrative tasks. This can be done locally or can be done remotely depending on customer requirements.
Oracle VM Servers: These are typically the servers that come embedded with a Xen hypervisor installation. A typical server can perform three different functions—the Server pool master function, the Utility function, or merely the VM Server function. The VM Agent is responsible for interacting with those functions and the VM Manager, thus notifying the user of the role(s) of the specific server.
- Server Pool Master role: This role is special for the server and interfaces with the outside world by communicating with the utility and VM servers. It also provides the load balancing capabilities by assigning the VM a VM Server that has the maximum resources available. We can only have one Server Pool Master in a pool.
- Utility Server role: This server will carry out heavy I/O tasks such as copy, move, and so on. A typical Virtual Data Center can have loads of ISO files and templates that are deployed across VM Servers. We will see more of this in the Oracle VM Management chapter. We can have several Utility Servers. The Pool Master Server chooses the Utility Server with maximum available CPU resources to carry out the intensive tasks, thus balancing the load.
- VM Server role: The main role of these servers is to host VMs. The Oracle VM agent installed on these servers communicates with the Utility Servers, Pool Master Server, and other VM Servers, thus aggregating all of the resources within the machines as a Single Logical Unit (SLU) to form a Sustainable Global Cloud Center.
Server Pools: Multiple Server Pools can be created within a Data Center. For instance, Pool 1 could be a pool for a typical production environment for an enterprise customer, Pool 2 could be a typical production pool for an SMB customer, and Pool 3 can be a SMB+ customer's delight. The pools act and function as logical units within a Data Center.
Storage: Storage could be local as well as part of a storage area network (SAN). Shared storage such as iSCSI or FC is necessary in order to perform live migration of VMs between VM Servers.

Oracle VM Server

The Oracle VM Server uses the Xen hypervisor technology and Oracle VM Agent. It includes a Linux kernel with support for devices, file systems, and so on. The Linux kernel runs as a dom0 and manages other DomU or VMs, called domains in Xen, the para-virtualization terminology. So essentially dom0 is the first guest booted and typically represents the physical machine by functioning as the supervisor module. Here the DomU could be a Linux, Solaris, or a Windows VM as we can see in the following image.

Xen hypervisor, Domains, and Virtual Machines

Oracle VM Server is designed so that the only entity that has full control of the system is the hypervisor or so called VMM. It is thin and is constructed using extremely well written code which basically handles your resources and interrupts.

In Xen terminology, we will see Domains, Guests, and VMs are often used interchangeably but they do have their differences. Simply said—Domain, with its virtual four-cores allows a VM to run on it, whereas a Guest is an operating system that runs within a Domain in para-virtualized or hardware virtualized mode (as explained earlier in the modes). A VM or to make it even more stylish, a Virtual Appliance is an operating system with the associated application running inside it.

VMs within an Oracle VM platform that run in para-virtualized modes need the necessary kernel modification and run at near-native speeds. Should the VMs run on hardware-assist virtualization, they run completely unmodified. Such hardware-assisted VMs are carefully monitored for instruction set changes and manipulations. The good part is that Operating Systems such as Microsoft Windows run fine as hardware-assisted VMs.

A lot of work, such as hardware detection in an Oracle VM Server, is performed by the Management domain also referred to as dom0. The VMs are often referred to as DomU. The dom0 is a complete kernel with a vast array of drivers and provides extensive support for file systems, volume management, and much more.

Looking quickly at the big picture, we get an idea of the basic Oracle Cloud Farm that could be built when the consumer starts using Oracle's VM Server and Oracle VM Manager on a large scale.

The following diagram is a high level view of how a typical Oracle Cloud farm can be built with Oracle VM Servers placed in various data centers and Oracle VM Manager managing the farms.

Key benefits

Learn quickly to install Oracle VM Manager and Oracle VM Servers

Learn to manage your Virtual Data Center using Oracle VM Manager

Import VMs from the Web, template, repositories, and other VM formats such as VMware

Learn powerful Xen Hypervisor utilities such as xm, xentop, and virsh

A practical hands-on book with step-by-step instructions

Description

Virtualization is taking the technology world by storm and dramatically helping organizations save money. Oracle VM is free and forked from the open source Xen hypervisor, which brings down your upfront costs for an agile data center. The robust capabilities and easy-to-use web interface of Oracle VM Manager helps administrators manage their Internal Data Center from anywhere in the world, helping us come closer to ubiquitous computing. This practical book will give you hands-on experience on how to manage your Virtual Machines using Oracle VM Manager. Equipped with step-by-step installation and management information you will not only learn to manage your Virtual Data Center but also will include this guide among the books you consider most essential. This book will take you into the various methods of importing Virtual Machines. You will learn to import VMs through HTTP/FTP, Repository servers, and even import other VM formats such as VMware VMs. You will also learn about the Xen utilities such as xm, xentop, and virsh. You will learn to manage your VMs through the simple and intuitive web interface of Oracle VM Manager. No matter how compact it may seem, this book covers all the essentials while keeping your learning experience to the point. The book has been deliberately written in a conversational manner so that you feel at home while learning Oracle VM Manager.

Who is this book for?

This book is for anyone who wants to learn virtualization with Oracle VM Manager and has some understanding and experience with virtualization; it is not an introductory book on virtualization but goes into detail explaining Oracle VM Servers and managing those VM Servers with Oracle VM Manager. The book is aimed at IT managers or administrators looking to learn a new set of skills to enhance their careers as well as those looking for more consolidated and comprehensive tools to manage virtual infrastructures. It will be helpful to VMware, Microsoft, and other virtualization administrators who are looking for robust and cheaper alternatives to otherwise expensive and proprietary virtualization software. Generally IT managers and non-core-IT staff may also benefit from chapters that teach how to manage the life-cycle of VMs and generally integrate the technology process into the people and processes of their organization.

What you will learn

Understand virtualization and learn to install Oracle VM Server

Install/Upgrade Oracle VM Manager

Manage VMs using Oracle VM Manager

Secure Oracle VM Manager

Learn Xen utilities such as xm, xentop, and virsh

Import VMs through HTTP/FTP, Repository, CD, and VMware VMs

Import Templates through HTTP/FTP, Repository servers, VMware templates and more

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Mark S. Millman Oct 08, 2009

Oracle VM Manager is a middle tier management front end to Oracle VM, which is really just XEN. I was hoping to find relevant information about Oracle VM itself, well XEN and the differences Oracle VM introduces but there is almost nothing on this essential topic.When the large type, white space, and far too many screen captures are taken into account this 226 page book is really not much more than a pamphlet. There is very little beyond the obvious repetition of the screen prompts and answers. Example: "You will be asked to confirm your action, as shown in the following screen shot:" (1/4 page picture with an OK button) "Your VM will be deleted, as shown in the following screen shot:" (1/4 page screen shot). Nine pages at the end of the book provide an abbreviated overview of xmtop, xm, & virsh command line utilities but you'd find this in the free Xen documentation.Save your money and buy a Xen book.

Amazon Verified review

Oracle VM Manager 2.1.2: Manage a Flexible and Elastic Data Center with Oracle VM Manager using this book and eBook

What do you get with Print?

Oracle VM Manager 2.1.2

Chapter 1. Introduction to Oracle VM

Virtualization: What is it?

Brief history of virtualization

Virtualization: What is it?

Brief history of virtualization

What forms of virtualization do we have?

Why should we virtualize?

Oracle VM

Oracle VM Manager

Oracle VM Server

Oracle VM Agent

Oracle VM Manager configuration

What about roles in Oracle VM Manager?

Oracle VM Server

Xen hypervisor, Domains, and Virtual Machines

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