Has Cloud Computing given SOA another big push?[Part 2]
By Brahma Acharya
Service design considerations for Cloud
In the first part I talked about how SOA and cloud computing converge. SOA does give us the ability to move around services to the cloud. However it might not be sufficient to design services the traditional way. Cloud brings with it a whole new way of doing things. Cloud enabled services should have the following consideration:
- Think Parallel: Design your services such that they can be run in parallel. Distributed processing framework like Hadoop and Map/Reduce have made it possible to run applications concurrently on multiple nodes without much effort. Also, think if the services can be run in a multi-processor environment on parallel threads.
- Cost implication: A cost benefit analysis is a must before the services are moved to a cloud. Cloud vendors typically charge for bandwidth usage, execution time and storage cost. As such it is important that the service designers and developers keep that in mind. Resources should be sparingly used and released at the earliest possible opportunity. Data transfer between consumers and clouds should be properly analyzed. For ex: If the service needs huge volume of input and output data it might not be a good candidate for Cloud. The overall cost of hosting such a service in the cloud may actually exceed than that of in-house maintenance.
- Design for failure: Cloud platforms are built to handle failures. However there could be downtime and network issues. The application should be designed and deployed in such a way that a failure in the cloud service doesn’t impact mission critical application. For ex: customers of an e-commerce application should be able to shop even though the disks are failing and data centers are down. Amazon’s Dynamo is one such platform which provides such reliability.
- Avoid Vendor lockdown: This is more relevant to the SaaS and PaaS model. Ideally the consumers should be able to move from one cloud provider to another without hassle and avoid any sort of vendor lockdown. This seems a little far-fetched at this point of time. Efforts are on to form an open standard for the Cloud. The opencloudmanifesto is a step in that direction. The Open group has also got into the act of providing an open standard.
- Regulations and laws: In certain cases it might be mandatory as to where the data can be hosted. Some laws like SOX and HIPPA might prohibit enterprise to move certain category of data out of their premises. Services should take these into account.
Conclusion
Cloud computing is revolutionary in nature. The benefits are too compelling to ignore. As the cloud space heats up, it is important to align your organization properly. Organizations who have implemented SOA will find it easy to move to a cloud environment. Such applications are not limited by the existing hardware and software. However sufficient due-diligence needs to be done before embarking on a full-fledged cloud exercise.
