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.
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.
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.
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.
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.
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.
Every time we look at a virtualization opportunity within a data center, customers are often exposed to fear, uncertainty, and doubt. It is a new technology; it aggregates everything and poses a challenge, not only to the siloed environment but also the siloed mentality. As the convergence takes place inside the cores, the "people and process convergence" needs to happen as well. The benefits of virtualization are simply irresistible.
Virtualization is a golden opportunity for organizations to do a technology refresh, providing a means to deliver IT in variety of ways to a highly aspirational consumer. Another major opportunity is towards Corporate Social Environmental Responsibility (CSER), especially energy, which helps organizations reduce their carbon footprints. But still the biggest advantage is—it saves a lot of money!
It helps organizations to:
Smart meter power and energy consumption as against the siloed approach where everything is always "turned on"
Redeploy resources as and when the demand is generated
Reduce and even contain the risk and cost of legacy applications on legacy hardware, which can now run seamlessly on state-of-the-art hardware
Always be available—there is a growing demand for continuous availability without increasing costs, and virtualization can adequately address both, the pain and the pleasure here
There are a lot more arguments, but keeping the focus simple we can safely say that with virtualization you can increase your productivity while reducing costs of operations.
Oracle VM is a platform, and its various components are discussed briefly in the subsequent sections. As we work through the rest of the book, we will install and configure these components.
Oracle VM Manager is installed on a physical machine which is eventually used to manage the Oracle VM Server pools. This is the WebUI interface, developed with Oracle's ADF. We will be using it to manage our Oracle VM platform. So this management console, which we can access in the cloud, is essentially the interface we will use to administer our Oracle VM platform for tasks such as:
Creating VMs from media, template, and other resources
Importing and exporting ISO files
Performing live migration
Creating and managing VMs and VM templates
Creating and managing (shared) storage
Other admin tasks such as shut down, restart, and so on
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:
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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.
As an Oracle VM Manager user, we can have the following roles—User, Manager, or Administrator.
User: This is a typical operator role where a user can carry out tasks such as creating and managing VMs and resources within those VMs.
Manager: With this role one can manage Server Pools, Servers, and resources. This user typically has all of the privileges of the User role as well.
Administrator: Besides managing user accounts, resources, and so on, this user has all of the permissions to manage Server Pools, Resources, and Virtual Machines.
As we go about the chapters in part II of this book, we will see in detail where these roles can be used.
Oracle VM Manager a Virtual Machine Lifecycle Management (VMLM) tool that helps us monitor the complete life cycle of a VM until its decommissioning. It covers other tasks such as importing, cloning, migrating, creating, and configuring server pools. It also covers management of VM Servers, resource management of templates, media, shared storage, and finally Oracle VM Manager Users and groups.
Oracle VM Manager is a feature rich tool and hopefully Oracle will continue its push into Cloud Computing by providing WebUIs for mobile applications where one can manage the Oracle VM platform with ease.
Throughout the book we will provide in depth detail about all aspects of using Oracle VM Manager, installing Oracle VM Server, and touch lightly all aspects of Oracle VM Management. We will go about installing the Oracle VM platform and managing it. Now let's take a look at 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.
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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.
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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.
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Clearly the advantages and the excitement of virtualization are hard to ignore. Besides the obvious fact that virtualization is an excellent business and technology convergence enabler, it is something that businesses have long strived for.
In the next chapter, we will install the VM Server. I hope that with this brief introduction of the Oracle VM platform and its components I was able to excite you to move ahead to the next chapter. Also, in the upcoming chapter we will explore the management of Domains, as well as the configuration and management of Oracle VM Manager and VM Server.
