We have heard a lot about iaas paas saas in cloud computing terms. IaaS stands for Infrastructure as service , PaaS stands for Platforms as a service and SaaS stands software as a service
Lets take a look at the key difference between them and examples of them
This is known as Infrastructure as a Service. Here the cloud provider gives the Physical infrastructure (network,storage, Computing power. Virtual machines) as service which can be accessed over internet. You can use that to install your software ,application deployment etc.The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, and deployed applications; and possibly limited control of select networking components
Users of IaaS can outsource and build a “virtual data center” in the cloud and have access to many of the same technologies and resource capabilities of a traditional data center without having to invest in capacity planning or the physical maintenance and management of it.
IaaS users are responsible for managing applications, data, runtime, middleware, and OSes.
IaaS Providers like Oracle still manage virtualization, servers, hard drives, storage, and networking.
Advantage here is that user can install any required platform on top of IaaS.
AWS Elastic Compute Service or EC2 is IaaS(Infrastructure as a Service). This is because Amazon takes the responsibility of networking, storage, server and virtualization and the user is responsible for managing the Operating System, middleware, runtime, data and application.
AWS Simple storage server is also an example IaaS
Oracle Elastic Compute service is also example of IaaS(Infrastructure as a Service)
Microsoft Azure Virtual Machine is IaaS
This is known as Platform as a Service. Here cloud providers deliver a computing platform, typically including operating system, programming-language execution environment, database, and web server. Application developers can develop and run their software solutions on a cloud platform without the cost and complexity of buying and managing the underlying hardware and software layers.The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, or storage, but has control over the deployed applications and possibly configuration settings for the application-hosting environment.
PaaS basically help developer to speed the development of app, saving money and most important innovating their applications and business instead of setting up configurations and managing things like servers and databases
Applications using PaaS inherit cloud characteristic such as scalability, high-availability, multi-tenancy, SaaS enablement, and more
AWS Elastic Beanstalk, Windows Azure, Heroku, Force.com, Google App Engine, Apache Stratos.
Oracle Database cloud server and Oracle exadata cloud database is classic example of PAAS(Platform as a service)
Microsoft sql Azure is a great example of PaaS
This is known as Software as a Service. Here cloud providers install and operate application software in the cloud and cloud users access the software from cloud clients. SaaS is sometimes referred to as “on-demand software” and is usually priced on a pay-per-use basis or using a subscription fee.Cloud users do not manage the cloud infrastructure and platform where the application runs . cloud Provider manage the infrastructure and platform both.
Cloud provider develop, maintain the software. Users just used the service through internet.The amount of configuration or setup at your end is minimal.Service Provider takes care of hardware, software updates, security and patches
With this offering, complete offloading is done to service provider. Organization just need to acces the software through internet.
Also there’s no need to invest in server capacity and software licenses. Simply adjust the subscription.
Some of the disadvantages of SAAS model are
a) The customer has no control over the system processing its data.
b) There is no control over which customers use the software; the software is used by a large amount of users.
c) Little or no control over the parameters of software. Only minimal configuration changes are allowed
d) Little control over deployment, upgrade and testing methodology (e.g. Dev, UAT, Live systems availability)
e) Currently only a limited number of software solutions are offered in the form of SaaS.
Google Apps, Salesforce, Workday, Concur, Citrix GoToMeeting, Cisco WebEx,Microsoft 365, Oracle HCM cloud, Oracle ERP cloud
We can summarize the difference with the below image
We can take Oracle Products as example to differentiate between these models
Another example could be Microsoft Azure
IaaS : Virtual machine, network storage
Paas: Azure sql database, Window Azure OS, NAPA
SAAS: Office 365, Sharepoint,Intune
A video from Youtube to help you understand it