Public Cloud

Accessible anywhere, scalable storage space, and a wealth of additional services: these features are what cloud computing brings to the table. Anyone thinking about using the cloud has to choose between different forms of provisioning, and the search is made even more difficult by the abundance of providers available on the market. A public cloud service is suitable for private users and SMEs. The public cloud offers many advantages, like user-friendliness and plenty of room to increase storage space. Since this virtual space contains sensitive data, the different services on offer should be examined carefully, as there are enormous discrepancies in data protection, scalability, and value for money.

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What is a public cloud?

The public cloud is a service that provides IT services publicly over the internet. The providers operate groups of networked servers, called “server farms,” for this purpose. As a user, you usually access the storage space through a web browser. The trick is that you only pay as much as you consume in terms of resources.

In addition, you save the purchase costs for the necessary hardware. This business model makes the public cloud attractive for young companies and medium-sized businesses who want to keep their IT budget low. Public cloud services often operate on a self-service basis. If you need more functionality or computing power, you can add more on your own.


The public cloud is a form of cloud computing provisioning. It provides on-demand access at any time to a networked pool of computing resources that are flexibly scalable and available to a large number of users on the public internet. Software, infrastructures, and platforms are offered by public cloud providers for a usage-based fee.

Public cloud features

Costs tailored to your needs: Each customer receives their own access for their cloud account. You can use your account to book individual services according to your needs. Instead of buying many long-term licenses, you can rent a CMS package for all employees, or graphics tools just for the designers, or test an analysis tool for your website for example. When it comes to public cloud services, billing is usually based on demand. This makes these solutions particularly flexible and a suitable choice if you want to access an application only once, or temporarily increase server capacities.

Web-based user interface: You often conduct your business with the respective provider through a browser interface. You book a service or capacity on your customer account, pay for it, and then unsubscribe when you no longer need it. Subscribed software from the public cloud can be accessed through the user interface, resulting in you needing less powerful hardware that would take up considerable storage on site. The internet connection is the only decisive factor in whether or not services will work, the rest is taken over by the respective provider.

Scalability: If high traffic overstrains a website’s performance, you can prevent downtime due to overloading by increasing resources. If you need less, then you can reduce the size just as quickly.

Efficiency: The cloud provider handles processes in the shortest possible time.

Economy: Compared to the private cloud, users need much less hardware. The data centers are located at the provider’s site. Software from the cloud does not have to be purchased as an expensive package, but is available in the required scope, often as a subscription with the latest version and corresponding support.

Reliability: Guaranteed standards are part of the business model. Suppliers take care of IT infrastructure maintenance and replace defective devices. Redundant hardware prevents failures.


Providers based in Europe and the US work in accordance with the highest security standards, offering scalability and flexibility. For example, IONOS offers a certified cloud server, with servers based in Germany, for your website.

Environmental protection: Cloud servers use storage and other resources efficiently by dividing them among many customers and tailoring them to their needs. Instead of using your own server inefficiently, you share storage space and computing capacity. Some vendors also use sustainably-produced energy.

Public cloud technical implementation

On the customer side, the public cloud requires very little equipment. Let’s assume that you integrate a large part of your IT infrastructure into the cloud. You hand over servers, runtime environments, and internal applications. In this scenario, all you need is an internet-enabled terminal and a browser. Depending on the task, employees operate these devices using a mouse and keyboard, through touchscreen input or with professional control panels. You don’t need your own server with a lot of storage space for databases and software, or lots of RAM for fast response times.

You connect to the public cloud through the public internet. The providers give you a web-based user interface as soon as you set up an account. Since the possible options range from individual applications to entire infrastructures, these user interfaces are designed very differently. For example, some customers only use a webmail interface that is limited to communication management; others book an office system or manage their web application on a provided platform.

You access your booked service through a service interface. The providers manage the backend and provide hardware – including server farms, data storage, and computers. Together, these devices form the cloud in which customers move. The cloud-hosts assign each service its own server space. In order to guarantee customer access at all times, redundancies are distributed on different servers.


A redundancy is more than a simple copy; it is a resource on another server that is congruent or very similar to how the original works. It serves as a back-up and is used when the first version fails. This can happen, for example, if the original resource loses contact with the server or becomes corrupted. Georedundancy also relies on locally separated server farms.

The cloud itself consists of several servers that are connected to a central server. The central server controls the network through “middleware,” which enables communication between all participating devices. The central server distributes tasks that were previously defined in protocols. Depending on the computing power required, the provider distributes storage space on the various servers. Some services require several machines.

For less storage-intensive services, the hosts use their devices efficiently. For this purpose, several virtual servers are located on one physical server. This virtualization, also known as a virtual machine, behaves like a real server with its own operating system. Customers access this virtual machine through an interface. Others use the same physical server, with their own virtualization through the web-based interface at their workstation. The virtual machine uses storage space efficiently and is freely scalable. Therefore, your service’s performance does not depend on your hardware’s capabilities.

The difference with the private cloud

The fundamental difference between public and private clouds are just those: public vs. private. Cloud computing in this tableau comprises three types of cloud access: on the one hand, there is the public cloud, which is available to everyone with an internet connection and sufficient budget. On the other hand, there is the private cloud, which is isolated from the public. Both forms have their respective advantages and disadvantages. That’s why some companies use a hybrid cloud, which is supposed to unite the best of both worlds.

Common to the three models is their streamlining effect on hardware and software resource consumption in the enterprise. If the IT environment is concentrated in the cloud, any performance peaks are distributed among the virtual servers being used.

Advantages of the public cloud Disadvantages of the public cloud
Registration and scaling are efficient, payment is based on the service principle and, depending on the service, also on a subscription basis. According to the GDPR, some data may not leave the company. If you manage personal data, you don’t have the free choice of any global provider. There are higher security standards.
Investments in company-owned hardware are very cost-effective with Lean Clients. Since the connection is through the public internet, the public cloud is generally considered more susceptible to security leaks.
No need to purchase expensive software licenses for all employees, here you can scale freely. Other customers may be able to affect the reachability or performance of your cloud services by using the same physical machine.
Experts monitor the server farms around the clock, take care of maintenance, and stock up on hardware. Some providers restrict your freedom of choice.
Providers tend to have capacities for georedundancy (physical separation of redundancies).

The architecture of public cloud deployment models

Providers use the public cloud architecture to provide services to varying degrees. It is also possible to use only one specific software, as well as to outsource entire structures. The architecture of the public cloud consists of so-called layers. It is therefore a layered architecture. Individual sub-areas are assigned to a specific layer. The layers are arranged hierarchically. A higher layer may access a deeper layer, but this does not work the other way round. A system can consist of one layer or of several layers. Then it is called multi-layer.

“Infrastructure as a Service” (IaaS), “Platform as a Service” (PaaS), and “Software as a Service” (SaaS) can be considered layers. These differ depending on the user level on which the offered service operates. While normal users use software, software architects work with the underlying platform to develop the software. This platform cannot be created or run without the surrounding infrastructure. Therefore, the different services build on each other like layers.

Within these three main layers, providers differentiate between specialized services like “Security as a Service,” “Storage as a Service,” or “High Performance Computing as a Service.” All the different models can be combined under the term “Everything as a Service” (XaaS). The abundance of public cloud options available “as a service” can be confusing. For this reason, only the three most important are presented here:

Software as a service (SaaS) from the public cloud

Just like music and movies are increasingly offered through streaming services, so is commercial software. Instead of having a physical copy on CD-ROM, users access the program through their internet connection. The software manufacturer usually hosts the application, which makes it a public cloud application. In some cases, the programs are hosted on an in-house server; this is referred to as a private cloud.

The SaaS model lets you choose from a number of applications that you put together into a package. The cloud provides you with security and performance updates. In addition, you always have the latest version, while a paid copy will eventually become obsolete – and then the support guarantee may no longer apply. With software as a service, you don’t have this problem. However, since payment is often made by subscription, you need to budget well to cover your running costs. After all, these costs are incurred even if you have little revenue.

Platform as a service (PaaS)

To run a program, you need a platform that supports the software. Platform as a service from a public cloud gives you just that. You can either access a runtime environment or a development environment through network access. The runtime environment provides a runtime system that you can run a website on, for example. The development environment gives you the space and tools to write programs yourself.

If you combine both services, the public cloud allows you to control a website’s entire lifecycle over the internet. In the development environment, you design the layout and write the code. Before publishing, you can also test the application in the environment, since you set it up on the runtime environment. To carry out all these steps, you would have needed a team of developers and designers, as well as hardware and special, costly software before the existence of the cloud.

PaaS services now outsource the environment and keep the platform accessible at all times. They provide compatible tools or middleware that converts formats and makes them compatible. Collaboration tools, like Messenger, are often part of the package. In development projects, secrecy is particularly important. To this end, as well as to shield you from hackers after your launch, a team of security experts will support your work. Good providers secure your platform through georedundancy and let you scale your project at any time.

Infrastructure as a service (IaaS)

Instead of buying your own server, you rent the server space or other hardware services like bandwidth or computing power with infrastructure as a service. This means you only pay for the scalable computing infrastructure to the extent that you need it. You work on a virtual server through a web interface. This enables you to test applications in different environments without purchasing them in full. In addition, the infrastructure is scalable. This gives you the potential for growth, but you can also give up free capacity. The server farm absorbs peak loads.

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This is what you should consider when choosing a public cloud provider

Whether IaaS, SaaS, or PaaS, there is a wide range of public cloud services on offer. Quality standards vary, however, and providers work differently. You will be able to find a service that meets your needs and fits your business.

Value for money

For budget calculations, it is essential to include recurring expenses like private cloud subscriptions. A high price pays depends on the features you get – and whether you use them at all. You just need a large infrastructure with a fully functional development environment if you want to build and run applications yourself.

Usually, you put together your own service package in your user account. However, some providers do not provide all the desired functions. Almost all service providers force the “vendor lock-in” i.e. a dependency on the provider. This makes it more difficult for customers to switch. In some cases, they use proprietary formats with which customers cannot use other applications (at least not easily).

Willingness to innovate

Are you constantly evolving and testing your own skills? Anyone who develops creative ideas in the cloud must be able to rely on their service provider. Data security should not be a problem due to redundancy. However, in order for you to be able to continue to make progress, your service provider must also remain innovative and offer you new opportunities. Indications of an innovative company are regular updates and an action plan that has been demonstrably adhered to. Sustainable growth is a sign of reliability, while too rapid growth quickly bursts the bubble of success.

User-friendliness and functionality

A service provider who does not constantly reinvent themselves is something you can live with. However, a service provider who does not offer the basic functions for you need for your website is useless. They should include tools and services that make your work easier. User-friendly public cloud providers facilitate communication between people and between applications. This also applies to communication between the experts from the cloud provider team and your own IT team. Without transparent communication, processes slow down and employees may lose motivation. Adjustments should be as simple as possible and implemented smoothly.


If you operate software or even entire development environments, including a communication platform through a public cloud, you inevitably put your personal data on the internet. You have sole access to your data through an interface assigned to your company. You may, however, share the server on which this data is stored with other users. In principle, your company is liable if data protection violations occur.

If your company is located in Europe, it is subject to the General Data Protection Regulation (GDPR). According to the law, personal data may not be stored outside the EU – except in secure third countries. This includes, for example, the USA because of the Privacy Shield. The safest option, however, is a provider based in Germany, a country that acts in accordance with local law, has appropriate contracts, and – most important of all – demonstrably operates its servers in Germany. As a company, you manage customer data or commit to security standards when it comes to business partners. You prove the quality or your protection with recognized certificates.


With cloud computing, companies rely on a lean client. This “lean” client is your end device or a program that cannot perform its work without a supporting server. On the one hand, the purpose of scaled-down hardware is to reduce acquisition and maintenance costs. On the other hand, you can scale their functional scope freely – thanks to the visualization of the cloud server.

So far, so good – but what about mobile devices? Make sure your cloud service provider offers compatible platforms that enable your company to use mobile SaaS. The same applies to web content your customers consume on mobile devices.


Companies and private users increasingly rely on cloud computing for their IT services. The public cloud is an important cornerstone of digitization. It enables a large audience to access data anytime and anywhere, even on the move. This reduces your own hardware and software acquisition costs. With the increasing expansion of broadband internet, the data cloud is developing into a serious alternative to your own in-house data center.

To achieve this, the digital infrastructure must also be further expanded in rural areas. Small and medium-sized enterprises will benefit from the scalability of the cloud and will be able to network better. European legislation and the German economy are working on making the cloud even more secure. The biggest difference in quality between the public and private cloud is subsequently being offset.

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