4.1 Summarize cloud-computing concepts Flashcards
What is cloud computing?
Service that provides on-demand resources over a network
Typically the internet
on-deman resources like server instances, file storage, databases, apps, etc.
What does Metered Utilization mean in the cloud?
The per-use billing for resources consumed by the cloud
The metering system tracks resource usage such as storage, processing, bandwidth, or active users, accessible to customers through a transparent reporting dashboard for billing transparency.
5 cloud characteristics?
- Shared resources
- Metered utilization
- Rapid elasticity
- High availability
- File synchronization
What does High Availability mean in the cloud?
Service experiences very little downtime
i.e. a service with ‘Five Nines’ or 99.999% availability experiences only 5 mins & 15 secs annual downtime.
What does Scalability mean in the cloud?
The costs involved in supplying the service to more users are linear
Linear = costs increase proportionally with user or resource additions
In a scalable system, doubling users doubles (or less) costs. If costs more than double, it’s less scalable. Scalability via adding nodes (horizontal/scaling out) or resources to each node (vertical/scaling up).
What does Rapid Elasticity mean in the cloud?
The system’s ability to handle changes to demand in real time
A highly elastic system maintains service/performance despite demand spikes and reduces costs during low-demand periods.
How do cloud providers provision & deprovision resources automatically?
via pooling of shared resources & virtualization
The layers of virtualization used in the cloud architecture allow the provider to provision more CPU, memory, disk, or network resource using management software, rather than (for instance) having to go to the datacenter floor, unplug a server, add a memory module, & reboot
What does Pooling of shared resources mean?
The cloud provider’s datacenter hardware isn’t dedicated to a single customer account
4 common cloud deployment models?
- Public
- Private
- Community
- Hybrid
How does a public cloud work?
Offered over the Internet by CSPs
(CSP = Cloud Service Provider) Cloud consumers are often referred to as tenants
What are the risks to public clouds?
Performance & security risks
How doe a private cloud work?
Being private to & owned by the organization
What is a community cloud?
Where orgs share the cost of a private or fully hosted cloud
This is usually done to pool resources for a common concern, like standardization & security policies
What is a hybrid cloud?
Combination of public, private, & community cloud
A travel organization might utilize a private cloud for its sales website but transition some functions to a public cloud, retaining sensitive data on-premises.
3 common cloud service models?
- IaaS
- SaaS
- PaaS
How does IaaS work?
Provisions IT resources
i.e. servers, load balancers, SAN components, etc.
What happens in a SaaS?
Clients acess software on a supplier’s server on a pay-as-you-go basis
Virtual infrastructure enables rapid on-demand app provisioning and cloud-based development and testing, bypassing the need for testing and deployment on client computers.
How does a PaaS work?
Provides resources somewhere between SaaS & IaaS
What does a typical PaaS solution deploy?
Servers, storage, network infrastructure, & a multi-tier web app/database platform
This platform could be based on Oracle or MS SQL or PHP & MySQL
What is the service provider responsible for in a PaaS?
The integrity & availability of the platform components
But you would be responible for the security of the app you created on the platform
What are desktops typically replaced by in a VDI?
Low-spec thin client computers
What happens when the thin client starts in a VDI?
Boots a minimal OS to log into a VM on company servers or cloud
How does a user’s thin client connect to a VM in a VDI?
Using a remote desktop protocol
like Microsoft Remote Desktop or Critix ICA
The thin client locates the correct image and authentication, either through 1:1 mapping or a connection broker.
What handles app processing & data storage in a VDE?
VDE = Virtual Desktop Environment
Server
The think client only needs to be powerful enough to display the screen image, play audio, & transfer mouse, key commands, & video, & audio information over the network
How can the virtualization server hosting virtual desktops be provisioned as?
An on-premises server or in the cloud
on-premises means on the same LAN as the clients
Centralizing data simplifies backup, support, and security measures against user errors. VDI enables easier IT infrastructure outsourcing.
Main disadvantage of VDI?
Users lack local processing ability during server & network failures
What is privisioning VDI as a cloud service referred to as?
DaaS
Desktop as a Service
What is VDI?
The use of VMs to provision corporate desktops
