Cloud computing is the on-demand delivery of IT resources over a network. In traditional data centers, compute and storage resources used to be allocated manually by a dedicated IT team. In the cloud, this process is fully automated, leading to increased agility and significant cost savings.
Types of clouds
Cloud types vary depending on who owns or operates them. It is also possible to use more than one cloud at a time in a hybrid or multi-cloud architecture.
Public cloud
Public clouds are owned and managed by a cloud service provider. All resources are shared between multiple tenants. Even though the public cloud market is dominated by three major players, hundreds of smaller public cloud providers exist all over the world and run their public cloud infrastructure on Ubuntu.
Private cloud
A private cloud is owned by an organization or an individual. All resources are exclusively dedicated to a single entity or a service. It runs on the organization’s premises or in an external data center. It is managed by the organization’s operations team or a managed service provider.
Managed cloud
Managed clouds are private clouds that are fully managed by a third-party organisation (aka managed service provider). The customer provides the hardware, but cloud operations and maintenance tasks are outsourced. The cloud can either run on the organisation’s premises or in the managed service provider’s data centre.
Micro cloud
Micro clouds are a new class of infrastructure for on-demand computing at the edge. They differ from the internet-of-things (IoT), which uses thousands of single machines or sensors to gather data, yet they perform computing tasks. Micro clouds reuse proven cloud primitives but with the unattended, autonomous and clustering features that resolve typical edge computing challenges.
Hybrid cloud
Hybrid cloud is a cloud computing architecture that consists of at least one public cloud, at least one private cloud and a hybrid cloud manager (HCM). It is one of the most popular trends in the IT industry, adopted by 82% of IT leaders, according to the Cisco 2022 Global Hybrid Cloud Trends Report.
Multi-cloud
Multi-cloud (also referred to as multi cloud or multicloud) is a concept that refers to using multiple clouds from more than one cloud service provider at the same time. The term is also used to refer to the simultaneous running of bare metal, virtualised and containerised workloads.
Cloud computing models
Cloud computing services are usually available to end users in the form of three primary models. Those include infrastructure-as-a-service (IaaS), platform-as-a-service (PaaS) and software-as-a-service (SaaS). Some more specific use cases exist too, such as container-as-a-service (CaaS). However, in essence, they are a subset of the main three.
IaaS
In the IaaS model, you provision resources. Those include the number of virtual CPUs (vCPUs), the amount of RAM, storage, etc. They come in the form of VMs or containers with a pre-installed operating system (OS). You manage everything up from there. IaaS is the most common cloud computing model as it allows for more freedom.
PaaS
In the PaaS model, you provision workloads. While you are still responsible for delivering application code and data management, the PaaS platform takes care of scheduling resources (usually containers) and manages them, including the OS, middleware and runtime. The PaaS model has never been widely adopted due to its overall complexity.
SaaS
In the SaaS model, you provision applications. They are deployed from pre-defined templates and can be configured according to your needs. Everything is managed by the cloud provider. Interest in the SaaS model is constantly increasing as it allows for full automation from the ground up.
| Legacy data centre | IaaS | Paas | Saas | |
|---|---|---|---|---|
| Applications | You manage | You manage | You manage | Cloud provider |
| Data | You manage | You manage | You manage | Cloud provider |
| Runtime | You manage | You manage | Cloud provider | Cloud provider |
| Middleware | You manage | You manage | Cloud provider | Cloud provider |
| O/S | You manage | You manage | Cloud provider | Cloud provider |
| Virtualisation | You manage | Cloud provider | Cloud provider | Cloud provider |
| Servers | You manage | Cloud provider | Cloud provider | Cloud provider |
| Storage | You manage | Cloud provider | Cloud provider | Cloud provider |
| Networking | You manage | Cloud provider | Cloud provider | Cloud provider |
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