Summary based on https://learn.microsoft.com/en-us/training/courses/az-900t00
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,Describe Cloud Concepts
1. Describe Cloud Computing
a. What is cloud computing
Cloud computing is the delivery of computing services over the internet by using a
pay-as-you-go pricing model. Computing services include common IT services such as virtual
machines, storage, databases and networking. It also expands to include things like Internet of
Things (IoT), machine learning (ML) and artificial intelligence (AI)
Because cloud computing uses the internet, it doesn’t have to be constrained by physical
infrastructure like a traditional datacenter, making it very scalable.
b. Cloud models
There are four different cloud models. They define the deployment type of cloud resources. The
main cloud models are: private, public, hybrid and multi-cloud
Private cloud:
A private cloud is a cloud (it delivers IT services over the internet) that is used by and dedicated
to a single entity. Private clouds provide great control for the company and it’s IT-department,
but costs more and has fewer benefits than public cloud.
A private cloud may be hosted from an on-site datacenter or in a dedicated datacenter offsite,
potentially by a third party that has dedicated that datacenter to your company.
Public cloud
A public cloud is built, controlled and maintained by a third party cloud provider, like Azure or
AWS. Anyone that wants to purchase cloud services can access and use resources. This
general public availability is the difference between public and private cloud.
Hybrid cloud
Hybrid cloud is a computing environment that combines a private cloud with a public cloud. A
hybrid cloud solution could be used to deal with increased, temporary demand. A service
running in a private cloud could use a public cloud to deal with spikes in demand.
Multi-cloud
This scenario is relatively new, but increasingly more likely. In a multi-cloud scenario you use
multiple cloud providers, for example AWS and Azure. Possibly because you’re migrating from
one provider to another, or you use different features from different providers.
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,The following table highlights a few key comparative aspects between the cloud models
Public cloud Private cloud Hybrid cloud
No capital expenditures to Organizations have complete Provides the most flexibility
scale up control over resources and
security
Applications can be quickly Data is not collocated with Organizations determine
provisioned and deprovisioned other organizations’ data where to run their applications
Organizations pay only for Hardware must be purchased Organizations control security,
what they use for startup and maintenance compliance, or legal
requirements
Organizations don’t have Organizations are responsible
complete control over for hardware maintenance and
resources and security updates
Azure Arc is a set of technologies that helps you manage your cloud environment, whether it’s
public, private, hybrid or even multi-cloud.
Azure VMware Solution is a tool that could be used to migrate your private cloud environment
to a public or hybrid cloud with seamless integration and scalability.
c. Consumption-based model
When comparing IT infrastructure models, there are two types of expenses, capital expenditure
(CapEx) and operational expenditure (OpEx)
CapEx is one-time, upfront expenditure, to purchase or secure resources. E.g. building a new
building, a datacenter, new servers for you on-prem datacenter, etc
OpEx is spending money on services or products over time, e.g. renting a building, leasing a
company vehicle or signing up for cloud services.
Cloud computing falls under OpEx because of the consumption-based model. You pay for
what you use (pay-as-you-go). Benefits of this model include:
- No upfront costs
- No need to purchase/manage costly infrastructure
- Ability to pay for more resources when needed / stop paying for resources when no
longer needed
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, 2. Describe the benefits of using cloud services
a. Describe the benefits of high availability and scalability in the cloud
Availability = uptime.
Azure has different service level agreements (SLA’s) for different services. 100% SLA is
practically impossible, services can’t be down for a second. It’s more common to have SLA’s of
99%, 99,9% and 99,95%
Scalability = the ability to handle demand
It refers to the ability to adjust resources to meet demand. An extra benefit of scalability is
pricing: pay-as-you-go principle meaning: If demand goes down, resources can be reduced and
price goes down. Vice versa for when demand goes up.
Scaling can be done in 2 ways: Horizontal and vertical.
Vertical scaling
Scaling up. Used for when you need more processing power in your already used virtual
machine. Done by adding more CPU or RAMS to the VM
Horizontal scaling
Scaling out. Used if experiencing a steep jump in demand. Done by adding more VM’s or
containers
Elasticity: The ability to scale when needed
Agility means that you can deploy and configure cloud-based resources quickly as app
requirements change. Scalability means that you can add RAM, CPU, or entire virtual
machines to a configuration. Elasticity means that you can configure cloud-based apps
to take advantage of autoscaling, so apps always have the resources they need. High
availability means that cloud-based apps can provide a continuous user experience
with no apparent downtime, even when things go wrong.
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