As name Suggest PaaS Model offers the run time environment or Platform for Cloud applications. It also offers development & deployment tools, required to develop applications.
PaaS Model has a feature of point-and-click tools that enables non-developers to create web applications. Google’s App Engine, Force.com are examples of PaaS offering vendors. Cloud Developer may log on to these websites and use the built-in API to create web-based applications.
Now, lets talk about Major Benefits of PaaS Model which can distinguish it from On-Premise Platform Service.
1) LOWER ADMINISTRATIVE OVERHEAD: Companies or Consumers need not to bother much about the administration because it’s the responsibility of cloud provider.
2) LOWER TOTAL COST OF OWNERSHIP: Consumer need not purchase expensive hardware, servers, power and data storage.
3) SCALABLE SOLUTIONS: It is very easy to scale up or down automatically based on application resource demands.
4) MORE CURRENT SYSTEM SOFTWARE: It is the responsibility of the cloud provider to maintain software versions and patch installations.
With above benefits, there are some challenges also which we need to consider before opt for PaaS deployments. Likewise SaaS Model, PaaS also place significant burdens on consumer’s browsers to maintain reliable and secure connections to the provider systems. Therefore, PaaS shares many of the issues of SaaS.
Here are top 3 Major Drawbacks, I considered companies/consumer need to think about.
1) LACK OF PORTABILITY BETWEEN PAAS CLOUDS: Although standard languages are used yet the implementations of platforms services may vary. For example, file, queue, or hash table interfaces of one platform may differ from another, making it difficult to transfer workloads from one platform to another.
2) EVENT BASED PROCESSOR SCHEDULING: The PaaS applications are event oriented which poses resource constraints on applications, i.e., they have to answer a request in a given interval of time.
3) SECURITY ENGINEERING OF PAAS APPLICATIONS: Since the PaaS applications are dependent on network, PaaS applications must explicitly use cryptography and manage security exposures.
Last but not the least, Paas can also classified as PaaS Types based on its functions. I will not in depth of each types at this stage but name will give you high level understanding.
1) Application Delivery-Only environments
2) Stand-alone development environments
3) Open Platforms as Service
4) Add-on Development Facilities.
SAP Cloud Solution Architect