provides a runtime environment. It allows programmers to easily create, test, run, and deploy web applications. You can purchase these applications from a cloud service provider on a pay-as-per use basis and access them using the Internet connection. In PaaS, back end scalability is managed by the cloud service provider, so end-user don't have to worry about managing the infrastructure.
PaaS includes infrastructure (servers, storage, and networking>
and platform (middleware, development tools, database management systems, business intelligence, and more>
to support the web application life cycle.
Example: Google App Engine, Force.com, Joyent, Azure.
PaaS providers provide the Programming languages, Application frameworks, Databases, and Other tools:
- Programming languages : PaaS providers provide various programming languages for the developers to develop the applications. Some popular programming languages provided by PaaS providers are Java, PHP, Ruby, Perl, and Go.
- Application frameworks : PaaS providers provide application frameworks to understand the application development easily. Some popular application frameworks provided by PaaS providers are Node.js, Drupal, Joomla, WordPress, Spring, Play, Rack, and Zend.
- Databases : PaaS providers provide various databases such as ClearDB, PostgreSQL, MongoDB, and Redis to communicate with the applications.
- Other Tools : PaaS providers provide various other tools that are required to develop, test, and deploy the applications.
Advantages of PaaS Cloud Computing LayerThe following are the advantages of PaaS Cloud Computing Layer -
- Simplified Development : PaaS allows developers to focus on development and innovation without worrying about infrastructure management.
- Lower Risks : No requirement for up-front investment in hardware and software. Developers just need a PC and a internet connection to start building applications.
- Prebuilt business functionality : No requirement for up-front investment in hardware and software. Developers just need a PC and a internet connection to start building applications.
- Instant community : PaaS vendors frequently provide online communities where the developer can get the ideas to share experiences and seek advice from others.
- Scalability : Applications deployed can scale from one to thousands of users without any changes to the applications.
Disadvantages of PaaS Cloud Computing Layer
- Vendor lock-in : One has to write the applications according to the platform provided by the PaaS vendor, so the migration of an application to another PaaS vendor would be a problem.
- Data Privacy : Corporate data, whether it can be critical or not, will be private, so if it is not located within the walls of the company, there can be a risk in terms of privacy of data.
- Integration with the rest of the systems applications : It may happen that a few applications are local, and some are in the cloud. So there will be chances of increased complexity when we want to use data which in the cloud with the local data.
Popular PaaS Providers
The below table shows some popular PaaS providers and services that are provided by them
|Google App Engine (GAE>
||App Identity, URL Fetch, Cloud storage client library, Logservice|
|Salesforce.com||Faster implementation, Rapid scalability, CRM Services, Sales cloud, Mobile connectivity, Chatter.|
|Windows Azure||Compute, security, IoT, Data Storage.|
|AppFog||Justcloud.com, SkyDrive, GoogleDocs|
|Openshift||RedHat, Microsoft Azure.|
|Cloud Foundry from VMware||Data, Messaging, and other services.|