Virtualization involves sharing underlying resources to enable a more efficient and agile use of hardware, which drives management efficiency through reduced personnel resourcing and maintenance. Virtualization provides the ability to run multiple operating systems (guests) and their associated applications on a single physical host. The guest is an isolated software instance that is operable with other guests also on the host, taking advantage of the resource abstraction capabilities provided by the hypervisor to dynamically utilize resources from the host as needed.
The Hypervisor
A hypervisor is a small form-factor software, firmware, or hardware that gives the impression to the guest operating systems that they are operating directly on the physical hardware of the host. It allows multiple guest operating systems to share a single host and its hardware. The hypervisor manages requests by virtual machines to access the physical hardware resources of the host, abstracts them, and allows the virtual machine to behave as if it is an independent machine. There are two types of hypervisors:
Type 1 Hypervisor
Commonly known as a bare-metal, embedded, or native hypervisor
Works directly on the hardware of the host and can monitor operating systems that run above the hypervisor
The hypervisor is small, as its main task is sharing and managing hardware resources between different guest operating systems
Type 2 Hypervisor
Installed after a traditional operating system and supports other guest operating systems running above it as virtual machines
Completely dependent on the host operating system for its operations
Management Plane
Simply stated, the management plane provides the CSP administrator with the ability to remotely manage any or all of the hosts, as opposed to having to visit each server physically to turn it on or install software on it. This is not to be confused with the management console that each cloud consumer is responsible for managing.
The key functionality of the management plane is to create, start, and stop virtual machine instances, and provision them with the proper virtual resources such as CPU, memory, permanent storage, and network connectivity. When the hypervisor supports it, the management plane also controls live migration of virtual machine instances. The management plane, thus, can manage all these resources across an entire farm of equipment.
The management plane software typically runs on its own set of servers and will have dedicated connectivity to the physical machines under management.
As the management plane is the most powerful tool in the entire cloud infrastructure, it will also integrate authentication, access control, and logging and monitoring of resources used.
The management plane is used by the most privileged users: those who install and remove hardware, system software, firmware, etc. The management plane is also the pathway for individual tenants who will have limited and controlled access to the cloud’s resources.
The management plane’s primary interface is the API, both toward the resources managed as well as toward the users. A graphical user interface (i.e., web page) is typically built on top of those APIs. These APIs allow automation of control tasks. Examples include scripting and orchestration of the setup of complex application architectures, populating the configuration management database, resource reallocation over physical assets, and provisioning and rotation of user access credentials.
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