Virtualization Flashcards
relies on a special type of software, known as a hypervisor, which creates the virtual hardware for devices. software to create the illusion of physical hardware.
Virturalization
many different varieties of hypervisors, including open source and commercial
Each instance of virtual hardware is called
a virtual machine, or VM.
The operating system (OS) installed within the VM is often referred to as
guest OS
the operating system of the underlying physical computer, which is called
host OS
To help you remember these terms, just think of the hypervisor as a host to a number of house guests called VMs.
access to the physical CPU and RAM resources as well as access to a virtual disk that the guest OS believes is a real, physical hard drive
guest OS
include special device drivers that you can install within the guest OS to gain performance improvements and access to features that would be otherwise impossible on physical hardware.
hypervisors
are able to host multiple VMs, each running its own guest OS and applications
Hypervisors
serves as a resource traffic cop in that it manages how each VM accesses and consumes the physical hardware resources, such as CPU, RAM, networking, and storage
still cannot communicate telepathically with one another. So, if you want them to talk to each other, you will have to install virtual network adapters in the VMs and configure their networking as you would do with your physical ser
VMs
look and feel like any other application that you may run on your laptop
Type 2 hypervisors
requires dedicated hardware and are installed as that machine’s operating system, making them more commonly found in data centers than in home networks.
Type 1 hypervisors
as VMware ESXi or the open-source KVM hypervisor, are operating systems that natively run virtual machines and are intended to be installed on a dedicated bare metal server.
Type 1 hypervisors
as VMware Workstation, is installed as an application within your existing computer or laptop operating system
Type 2 hypervisor
complete access to the underlying hardware of the physical computer, which alleviates the performance penalty that Type 2 hypervisors commonly face.
Type 1 hypervisor
very little information to the console screen of the host computer. While there may be a limited user interface for troubleshooting the hypervisor directly, all administration is typically performed from another computer, such as your laptop. On your laptop, you would direct a web browser to the IP address or hostname of the hypervisor to access its web-based administration portal.
Type 1 hypervisors
you can see the basic troubleshooting interface on its monitor but must use a web browser on a separate computer to administer the hypervisor and the VMs running on it.
are typically connected to the network just like any other physical computer. Users that need to connect to a VM typically are not granted access to the hypervisor configuration portal; rather, they are given an IP address or hostname for the VM that they need to connect to.
VMs
sometimes referred to as a hosted hypervisor, is installed as an application on personal computers or laptops. This allows the user to run different VMs that all share the laptop or computer’s hardware resources. This allows you to run operating systems within a VM other than what was natively installed on your computer or laptop
Type 2 hypervisor
they are installed and run as a regular application on your computer or laptop
Type 2 hypervisors
This means two things: first, the hypervisor is competing for hardware resources with all the other running applications on your computer; and second, the hypervisor does not have direct and unrestricted access to the physical hardware but instead must send all your VM’s hardware requests through your computer’s operating system
Type 2 hypervisors
Both issues can lead to degraded performance within your VMs, but slower performance may be far more desirable than buying and carrying around separate computers
What is a hypervisor?
A software tool used to host virtual systems.
Hypervisors are like a layer of system software between computer hardware and virtualized systems. Hypervisors can be used to control and manage access to hardware resources by one or more virtual systems.
offering are server virtualization, storage virtualization, and network virtualization
IaaS
you are responsible for managing more things, such as the virtual machine configuration, its operating system, and all the patches that it requires.
IaaS
You are responsible for people, data, applications, operating system, & virtual networks
Iaas
Service is responsible for Hypervisors, servers & storage, and physical networks
Iaas
you are responsible for people, data, and applications
PaaS
service is responsible for
operating system, virtual networks, hypervisors, servers and storage, and physical networks
you are responsible for people and data
SaaS
service is responsible for applications, operating system, virtual networks, hypervisors, servers & storage, and physical networks
SaaS
The cloud provider allows you to choose the number of CPUs, the amount of RAM, the amount of storage, and even the number of network cards in the VM.
Server virtualization
cloud providers offer you storage solutions that can expand in size or change in performance based on your business needs. When creating your VMs, you may be given the choice to provision regular storage at the normal price or very fast storage at a premium price.
storage virtualization
cloud providers the ability to create virtual private cloud (VPC) networks for each of their customers, keeping each VPC network isolated from the others. The VPC network may also have routers and firewalls that allow your VMs access to the internet or to other data centers around the world.
network virtualization
flagship product offering in the infrastructure as a service (IaaS) cloud service model, virtual servers are also used by cloud providers behind the scenes to deliver their customer-facing platform as a service (PaaS) and software as a service (SaaS) products.
server virtualization
cloud provider typically has little to no interaction with your virtual machines, leaving you with the responsibility to protect them from disaster (via replication) and data loss (via regular backups)
IaaS cloud provider is responsible for repairing their equipment; however, depending on your support agreement with the cloud provider, they may or may not be financially liable to you for the outage or responsible for restarting your virtual server following the outage.
in most legal jurisdictions, the cloud provider is not obligated to automatically back up your data, keep archive copies of your data, or even move your data to another location without your express consent and direction
IaaS
When deploying a production application to the cloud, build redundancy and disaster recovery into your design by deploying at least two of everything: one instance in a nearby data center for production use, and one instance in a geographically distant data center for safekeeping.
a platform on which to deploy your application or you simply need a database without the hassle of managing the server
PaaS
cloud provider is responsible for the virtual servers and, in some cases, the services that run on top of them, such as a database engine, and provides you with a platform on which you can run your code or store your data.
You have the ability to log in and upload your code, but they maintain the server for you, including the virtual hardware, guest OS, web services, and the patching for the OS and web services.
PaaS
attractive for application developers because it allows them to deploy their code to an application runtime environment, such as Java
is not intended to imply that there are no servers, but rather that the consumer of the service (the developer in this case) typically is not even made aware of the number of servers being used in the back end to run the application.
serverless computing
These solutions are also gaining in popularity because they can quickly deploy and then scale new applications with minimal effort required by the IT operations team, thereby increasing the reaction time of IT to changing business needs.
PaaS
allows consumers to store and potentially publish information without the need to manage the underlying applications or infrastructure.
SaaS
The term software in SaaS could represent nearly anything you consume over the internet. A few examples include social media (Facebook), word processing (Office 365)
Which cloud service model requires the customer to be responsible for operating systems?
IaaS
Infrastructure as a service means that the customer is responsible for all software and data beyond the hypervisor. The cloud service provide is responsible for the hypervisor and all hardware in the system.
company purchases or leases the computer, storage, and networking hardware and maintains the data center facilities. If a failure occurs, the company is responsible for repairing the problem themselves because all the equipment belongs to and is managed by them.
private cloud
The primary advantage of a private cloud is the ownership and control that a company has over the equipment.
The company may lease space in a commercial data center and operate the equipment there
co-locating, or a “co-lo” solution
the company is co-locating its equipment with the commercial data center’s equipment
the ownership and maintenance of the underlying infrastructure and facilities. the cloud provider is responsible for maintaining the hardware and repairing the infrastructure instead of the customer.
public cloud
In some cases, public cloud providers may have a higher level of security than the customers they host.
when multiple tenants share the same physical resource
multi-tenancy,
there are potential security and performance implications because you are sharing hardware with other companie
uncommon in the commercial sector but may be found in universities or government agencies. These clouds are data centers that are jointly owned and operated by the tenants. added benefit that the maintenance and management of the underlying infrastructure is shared by all the tenants.
Community clouds
most commonly associated with companies that extend their applications and services between their own data center and that of a public cloud provider’s
hybrid cloud
as a way to host most of their services in the public cloud with the exception of the few applications that are subject to regulatory controls and must remain at an on-premises data center.
customer will require a dedicated connection between their on-premises data center and the public cloud provider. This connection may be a virtual private network (VPN) established over the internet or a dedicated wide area network (WAN) connection maintained by a telecommunications provider.
hybrid cloud computing
the concept of leveraging the services of multiple public cloud providers, such as hosting your website at AWS and GCP and balancing the users between these providers
Multi-cloud
This concept, in practice, can add redundancy and flexibility.
