
Cloud is certainly one of the trendy technologies and is a shift in the tradition of computing ensuring faster methods of coming up with computing solutions, infrastructure solutions and application layers.
Cloud computing is nothing but a model or network where a program or applications accessed by many devices or servers at a time run. In layman language, it is a virtual storage, and can also be accessed remotely. Thus, it rewards users with cost savings, increased productivity, performance, efficiency, and security.
Public cloud, Private cloud, and Hybrid cloud are the cloud deployment model.
Public Cloud

Public cloud is delivered to multiple users over the public internet by the third party. It is a paid service or free of charge to anyone who wishes to purchase or use them. With a public cloud, all hardware, software, and other supporting infrastructures are owned and managed by vendors or cloud providers.
The common use case scenarios of a public cloud are web-based mail, online office applications, storage, testing, or deploying a blog.
Advantages
Lower cost – It follows the pay-as-you-go pricing model where users have to pay for what they use which allows them not to purchase hardware or software.
No maintenance – Maintenance is done by cloud service providers.
High scalability – On-demand resources are available to meet business requirements which means there is no need to invest in hardware to scale up the on-demand infrastructure.
High reliability – A vast network of servers ensure failover strategies against downtime and outages.
Disadvantages
Performance – The same hardware is shared among multiple users that may affect the performance because of server load.
Security – Users don’t have control over infrastructure and the service level policies and compliances are administered by the cloud providers.
Private Cloud

Private cloud is operated solely for a single organisation which is hosted and managed internally at the users’ on-site data centers or by a third party. The services and infrastructures are always maintained on a private network and the hardware and software are solely customised to one organisation or user. Thus, it makes it easier to customise resources to meet on-demand requirements.
Mostly government agencies, financial institutions, or any mid to large size organisation with business-critical operations aiming for enhanced control over their environment prefer to use a private cloud.
Advantages
More Flexibility – Private cloud service users can customise their resources based on their business requirements.
More control and security – It is solely controlled and the resources are not shared with others, so higher levels of security, privacy, and control are possible.
More scalability – Private cloud services offer more scalability comparatively on-premise infrastructures.
Disadvantages
Cost – More expensive than the public cloud as building an on-premise private cloud can stretch the budget.
More maintenance – It needs a separate in-house IT administration set-up for its maintenance as the private cloud service set-up is expensive, time-consuming, and needs more maintenance.
Hybrid Cloud

The hybrid cloud is a combination of on-premise infrastructure or private cloud with public cloud where sensitive data or applications are kept inside the organisation’s network using a private cloud, and other services are hosted outside the organisation’s network using a public cloud.
For instance, a hybrid cloud user can deploy their website on a public cloud for leveraging scalability benefits and can deploy database in a private cloud for security and privacy purposes.
The hybrid cloud also allows the movement of data and apps between the two environments that means users can use them interchangeably in day-to-day operations.
Advantages
Control – Users can make private infrastructure for sensitive data and application which require low latency, and for less sensitive workloads they can maintain public infrastructure.
Flexibility – Benefits of additional resources in public clouds are available in need. With public cloud infrastructure immediate and effective response to the unpredictable demand surge is possible, and also scaling back down when spike subsides won’t affect the functioning in private cloud infrastructure.
Ease and agility – Hybrid cloud allows users to modernise legacy applications and data gradually and migrating them to the public cloud comfortably.
High reliability – Workloads distributed across multiple data centers ensure disaster recovery, failover, and ultimately smoothens the service.
Disadvantages
Elevated costs – Maintenance and optimisation of hybrid cloud’s on-premise segment can not be budget-friendly especially for the smaller organisation.
Infrastructure complexity – For better service and delivering maximum benefits public and private infrastructure must be firmly linked. Setting-up and managing hybrid clouds become complex as the number of clouds proliferates especially when sourced from different providers.
One Point View

The Last Corner
All cloud service deployment techniques have their pros and cons. It is the user’s or organisation’s requirements or use-cases which will determine the suitable type of cloud deployment for their workloads.