what-is-the-cloud ماهى السحابة وتعريفها وكيف تعمل السحابة The "cloud" refers to servers that are accessed over the Internet, and the software and databases that run on those servers.
Cloud servers are located in data centers all over the world.
With cloud computing,
users and businesses do not have to manage physical servers themselves or run software applications on their own devices.
what-is-the-cloud The cloud allows users to access the same files and applications from almost any device,
because the computing and storage take place on servers in a data center, rather than being accessed locally on the user’s device .
This is why a user can log into their Instagram account
on a new phone after their old phone breaks and still find their old account intact,
with all the photos, videos, and conversation history .
It works the same way with cloud email providers
such as Gmail or Microsoft Office 365 , and with cloud storage providers like Dropbox or Google Drive.
Also: For businesses, moving to cloud computing eliminates some IT costs and overhead
For example, they no longer need to update and maintain their own servers,
as the cloud vendor they use will do that. This particularly affects small businesses
that may not have been able to afford their own in-house infrastructure but can outsource their infrastructure needs
via the cloud. The cloud can also make it easier for businesses to operate internationally,
because employees and customers can access the same files and applications from anywhere.
How Does Cloud Computing Work? Cloud computing is possible because of a technology called virtualization.
Virtualization allows the creation of a simulated, digital-only “virtual” computer that behaves as if it were a physical computer with its own hardware. The technical term for such a computer is a virtual machine.
When properly implemented, virtual machines on the same host machine are sandboxed from one another,
so they do not interact with each other at all,
and the files and applications from one virtual machine are not visible to the other virtual machines even though they are running on the same physical machine.
Also: Virtual machines also make more efficient use of the hardware hosting them. By running many virtual machines at once,
one server can run many virtual “servers,” and a data center becomes like a whole collection of data centers,
capable of serving many organizations.
Therefore, cloud service providers can offer the use of their servers to far more customers at once
than they otherwise could, and they can do so at a low cost.
Even if individual servers go down,
cloud servers in general should be always online and always available.
Cloud vendors generally back up their services on multiple machines and across multiple regions.
Users can access cloud services either through a browser or through an app,
connecting to the cloud over the Internet – that is, through many interconnected networks –
regardless of what device they are using.
What Are the Main Cloud Computing Service Models? saas-paas-iaas Software as a Service (SaaS ): Rather than users installing an application on their devices,
SaaS applications are hosted on cloud servers, and users can access them over the Internet.
SaaS is like renting a house: the landlord maintains the house,
but the tenant uses it mostly as if they owned it.
Examples of SaaS applications include Salesforce , MailChimp , and Slack .
Platform as a Service (PaaS ): In this model, companies do not pay for hosted applications;
instead they pay for the things they need to build their own applications.
PaaS vendors provide everything needed to build an application,
including development tools, infrastructure, and operating systems over the Internet.
PaaS can be compared to renting all the tools and equipment needed to build a house,
rather than renting the house itself. Examples of PaaS include Heroku and Microsoft Azure .
Infrastructure as a Service (IaaS ): In this model, the company rents the servers and storage it needs from a cloud provider.
They then use that cloud infrastructure to build their own applications.
IaaS is like a company renting a plot of land on which they can build whatever they want – but they need to provide their own construction equipment and materials.
IaaS providers include DigitalOcean, Google Compute Engine , and OpenStack .
Previously, SaaS, PaaS, and IaaS were the three main models of cloud computing , and essentially all cloud services fell into one of these categories. However, in recent years a fourth model has emerged:
Function as a Service (FaaS ): FaaS, also known as serverless computing,
breaks cloud applications down into smaller components that only run when needed.
Imagine if it were possible to rent a house one small piece at a time
For example, the tenant only pays for the dining room at dinner time, the bedroom while they sleep, the living room while they watch TV, and when they are not using these rooms, they do not have to pay rent for them.
FaaS or serverless applications still run on servers, as do all of these cloud computing models. But they are called “serverless” because they do not run on dedicated machines, and because the companies building the applications do not have to manage any servers.
Also Serverless functions scale, or replicate, as more people use the application – imagine if the tenant’s dining room could expand on demand when more people come over for dinner! Learn more about serverless computing (FaaS).
If: What Are the Different Types of Cloud Deployments? Unlike the models discussed above, which define how services are delivered via the cloud, these different types of cloud deployments relate to where the cloud servers are located and who manages them.
The most common cloud deployments are:
Private Cloud: A private cloud is a server, data center, or distributed network dedicated entirely to one organization. Public Cloud: A public cloud is a service managed by an external provider and may include servers in one or more data centers. Unlike private clouds, public clouds are shared by multiple organizations. Using virtual machines, individual servers can be shared by different companies, a situation called ” multi-tenancy ” because many tenants rent server space within the same server. Hybrid Cloud: Hybrid cloud deployments combine public and private clouds, and may also include legacy on-premises servers. An organization might use a private cloud for some services and a public cloud for others, or may use the public cloud as a backup for their private cloud. Multi-Cloud: Multi-cloud is a type of cloud deployment that involves using multiple public clouds. In other words, an organization with a multi-cloud deployment rents virtual servers and services from several external providers – to continue the analogy used above, this is like renting several adjacent plots of land from different property owners. Multi-cloud deployments can also be hybrid clouds, and vice versa.
