A cloud is called a “public cloud” when the services are rendered over a network that is open for public use.Public clouds are constructed using pooled shared physical resources, and accessible over a public network such as the internet. Public clouds, however, provide services to multiple clients using the same shared infrastructure.Generally, public cloud service providers like Amazon AWS, Microsoft and Google own and operate the infrastructure and offer access only via Internet (direct connectivity is not offered).
Pros of Public cloud
Ultimate scalability: Public cloud is vast pool of resources that can respond seamlessly the demand of individuals as well as enterprises.
Cost effective: Public cloud is cost effective because it use shared resources.
Utility style costing: Pay as you go is payment model for public clouds.User or enterprise can use resources of public cloud on demand and pay as as per use.
Reliability: Public cloud infrastructure provides robust availability by different techniques like load balancing etc.
Location independence: Public clouds use infrastructure spread across globe.
Cons of Public cloud
Security issues :
Public cloud providers offer the same infrastructure to multiple clients and scale up resources on a real-time basis. When you share CPU, memory and data center resources with multiple users, there is a risk for enterprise and customer data.
Data deletion techniques need to be checked. Business data that is deleted or moved needs to be completely erased from the datacenter. However, you do not have the complete control on the datacenter infrastructure to use proper data sanitization techniques. If data is not properly erased, it can be accessed by other users and used in a harmful manner.
Limited Control on Technologies: Public Cloud users do not have any control on the business processes managing the cloud.
Compliance issues: For compliant organizations need to disclose the location where data has been stored.But for cloud data gets stored at different datacenters across globe that makes difficult for companies to adopt public cloud.