Understand Cloud Concepts Flashcards
What’s a virtual machine?
A software emulation of a physical computer.
How do you call a snapshot of a running VM?
An image.
What does it mean to scale up (vertically)?
It means to increase the memory, storage, or compute power on an existing virtual machine.
What does it mean to scale out (horizontally)?
It means to add extra virtual machines to power your application.
For example, you might create many virtual machines configured in exactly the same way and use a load balancer to distribute work across them.
What is CapEx?
Capital Expenditure (CapEx) is the spending of money on physical infrastructure up front, and then deducting that expense from your tax bill over time. It is an upfront cost, which has a value that reduces over time.
What is OpEx?
Operational Expenditure (OpEx) is spending money on services or products now and being billed for them now. You can deduct this expense from your tax bill in the same year. There is no upfront cost, you pay for a service or product as you use it.
What are the advantages of public cloud?
- high scalability/agility
- pay-as-you-go pricing (no CapEx costs)
- maintenance or updates of the hardware handled by provider
- minimal technical knowledge required to set up and use
What are the disadvantages of public cloud?
- specific security requirements cannot be met by using public cloud
- some government policies, industry standards, or legal requirements cannot be met
- you cannot manage them as they may wish
- unique business requirements, such as having to maintain a legacy application might be hard to meet
What are the advantages of private cloud?
- complete control over the resources
- complete control (and responsibility) over security
- can meet strict security, compliance, or legal requirements in ways a public cloud might not be able to
What are the disadvantages of private cloud?
- upfront CapEx costs and must purchase the hardware for startup and maintenance
- limited agility
- require IT skills and expertise that’s hard to come by
What’s IaaS?
It is the most flexible category of cloud services. It aims to give you complete control over the hardware that runs your application.
What are the common scenarios to use IaaS?
- migrating workloads
- test and development
- website hosting
- storage, backup, and recovery
What’s Paas?
It is a complete development and deployment environment in the cloud.
What are the common scenarios to use Paas?
- development framework
- analytics or business intelligence
What’s SaaS?
It is software that is centrally hosted and managed for the end customer.
