|Oracle® VM Manager User's Guide
Part Number E15441-02
|PDF · Mobi · ePub|
This chapter gives an overview of Oracle VM Manager. It includes the following topics:
Virtualization is the ability to run multiple virtual machines on a single piece of hardware. The hardware runs software that enables you to install multiple operating systems capable of running simultaneously and independently, in their own secure environment, with minimal impact on performance. Each virtual machine has its own virtual CPU, network interfaces, storage, and operating system.
With increased server provisioning in the datacenter, several factors play a role in stifling growth. Increased power and cooling costs, physical space constraints, man power, and interconnection complexity all contribute significantly to the costs and feasibility of continued expansion.
Commodity hardware manufacturers have begun to address some of these concerns by shifting their design goals. Rather than focusing solely on raw gigahertz performance, manufacturers have enhanced the feature sets of CPUs and chip sets to include lower wattage CPUs, multiple cores per CPU die, advanced power management, and a range of virtualization features. By employing appropriate software to enable these features, several advantages are realized:
Server Consolidation: By combining workloads from a number of physical hosts into a single host, a reduction in servers can be achieved as well as a corresponding decrease in interconnect hardware. Traditionally, these workloads would need to be specially crafted, partially isolated and well behaved, but with new virtualization techniques none of these requirements are necessary.
Reduction of Complexity: Infrastructure costs are massively reduced by removing the need for physical hardware, and networking. Instead of having a large number of physical computers, all networked together, consuming power and administration costs, fewer computers can be used to achieve the same goal. Administration and physical setup is less time consuming and costly.
Isolation: Virtual machines run in sand-boxed environments. They cannot access each other, so if one virtual machine performs poorly, or crashes, it does not affect any other virtual machine.
Platform Uniformity: In a virtualized environment, a broad, heterogeneous array of hardware components is distilled into a uniform set of virtual devices presented to each guest operating system. This reduces the impact across the IT organization: from support, to documentation, to tools engineering.
Legacy Support: With traditional bare-metal operating system installations, when the hardware vendor replaces a component of a system, the operating system vendor is required to make a corresponding change to enable the new hardware to function properly (for example, an ethernet card). As an operating system ages, the operating system vendor may no longer provide hardware enabling updates. In a virtualized operating system, the hardware remains constant for as long as the virtual environment is in place, regardless of any changes occurring in the real hardware, including full replacement.
Oracle VM is a platform that provides a fully equipped environment to better leverage the benefits of virtualization technology. Oracle VM enables you to deploy operating systems and application software within a supported virtualization environment. The components of Oracle VM are:
Oracle VM Manager: Provides the user interface, which is a standard ADF (Application Development Framework) web application, to manage Oracle VM Servers, virtual machines, and resources. Use Oracle VM Manager to:
Create virtual machines from installation media or from a virtual machine template
Delete virtual machines
Power off virtual machines
Import virtual machines
Deploy and clone virtual machines
Perform live migration of virtual machines
Import and manage ISOs
Create and manage virtual machine templates
Create and manage shared virtual disks
Oracle VM Server: A self-contained virtualization environment designed to provide a lightweight, secure, server-based platform to run virtual machines. Oracle VM Server is based upon an updated version of the underlying Xen hypervisor technology, and includes Oracle VM Agent.
Figure 1-1, "Oracle VM Architecture" shows the components of Oracle VM.
This section describes the configuration structure of Oracle VM Manager.
As shown in Figure 1-2, when you deploy Oracle VM Manager, the following components are involved:
Oracle VM Manager Host: The host machine on which Oracle VM Manager is installed is known as an Oracle VM Manager host. It provides the interface where most of the virtual machine management tasks are performed. Its main function is to forward operational commands from users to other, possibly remote, servers and display their results.
Servers: An Oracle VM Server, once added to a server pool, is assigned with one, two, or even all three functions, namely, Server Pool Master function, Utility Server function, and Virtual Machine Server function.
Oracle VM Agent provides the interface to each server function. Therefore, if An Oracle VM Server is assigned as a Server Pool Master only, then the Server Pool Master agent component is activated. Otherwise, if it is assigned as both a Server Pool Master, and a Utility Server, their respective agent components are activated, and so on.
An Oracle VM Server can perform one, two, or all of the three functions described below:
Server Pool Master: The Server Pool Master is the core of the server pool operations. It acts as the contact point of the server pool to the outside world, and also as the dispatcher to other servers within the server pool.
The load balancing is implemented by the Server Pool Master. For example, when you start a virtual machine, the Server Pool Master chooses a Virtual Machine Server with the maximum resources available to run the virtual machine.
There is only one Server Pool Master at one time in a server pool. If the Server Pool Master fails or becomes unavailable, the role is automatically assigned to another Oracle VM Server in the server pool, if one available.
Utility Server: The Utility Server is responsible for I/O intensive operations such as, copying, or moving files. Its function focuses on the creation and removal operations of virtual machines, servers, and server pools.
There can be one or more Utility Servers in a server pool. When there are several Utility Servers, the Server Pool Master chooses the Utility Server with the maximum CPU resources available to conduct the task.
Virtual Machine Server: The primary function of the Virtual Machine Server is to run virtual machines, thus acting as a hypervisor. Oracle VM Agent is set up on the Virtual Machine Server to establish communication between the Server Pool Master, other Utility Severs, and Virtual Machine Servers.
There can be one or more Virtual Machine Servers in a server pool. When there are several Virtual Machine Servers, the Server Pool Master chooses the Virtual Machine Server with the maximum resources available (for example, memory) to start and run the virtual machine.
Server Pools: A server pool is an autonomous region that contains one or more Oracle VM Servers. A server pool presents a unified view of the storage in which the virtual machines reside. Each server pool must have its own shared storage.
The server functions described above can be deployed in a server pool in a variety of ways as shown in Figure 1-2. For example, in Server Pool 1, each one of the three functions is implemented on an individual Oracle VM Server. In Server Pool 2, all of the three functions are performed by a single Oracle VM Server.
In medium to large scale environments with more than just a few virtual machines in a Server Pool, it is recommended that the Server Pool Master and Utility Server functions reside together or individually on a separate and dedicated physical server that does not host any guest virtual machines, as illustrated in Server Pool 3. This is to prevent any significant Server Pool Master or Utility Server usage from impacting the performance of the workloads hosted in the guest virtual machines.
Storage: A storage resource is mounted to store virtual machines, external resources, and other data files that are shared among Oracle VM Servers in the server pool. In order to perform Live Migration of virtual machines between separate physical machines in the server pool, each machine involved must have shared access to storage.
As a user of Oracle VM Manager, you can have one of three roles: User, Manager, or Administrator.
User: Creates and manages virtual machines, and also imports resources.
Manager: Manages the server pools, resources, and servers. A manager also has all the privileges of the User role.
Administrator: Performs administration tasks such as managing user accounts, importing resources, and approving imported resources. An Administrator also has all privileges of the User role and the Manager role.
Table 1-1 briefly lists the available functions for each user role.
Oracle VM Manager provides the following main features:
Virtual machine life cycle management. This includes creating virtual machines from either installation media or from templates, starting, logging in, shutting down, and deleting virtual machines.
Importing virtual machines
Cloning virtual machines
Deploying virtual machines
Migrating virtual machines
Creating and configuring server pools
Managing resources, including ISO files, virtual machine templates, virtual machine images, and shared virtual disks
Managing Oracle VM Manager users, and groups