IaaS or “Infrastructure as a Service” is a concept and frequently offered product in the Cloud Computing space that currently appears to have as much pervasiveness as any of the other service types. What you wind up with, in the majority of cases, is an operating system running on a clustered hypervisor architecture. So – to the end-user or customer, it’s just like having a dedicated server – Perhaps with some added perks like only paying for computing resources used or High Availability at the hypervisor level, insulating your operating system from some hardware failures, etc.
If you are building your own private Cloud, or building one to host your customers’ workloads, IaaS can be an important consideration, because “Infrastructure isn’t free” – and is a workload that you will need to manage. If you’re on the other side of the equation – the customer side, what value is there in paying for an operating system, part of a hypervisor, part of a shared infrastructure, and possibly part of the administrative staffing costs?
Is it because your application or workload isn’t capable of running as a Software as a Service (SaaS) service? The chances are that putting it in a Cloud infrastructure won’t help it much either. Is it because you have a need to connect to an operating system, perhaps to make your purchase more tangible? Again, this is not usually a good reason to invest in Cloud Computing.
Almost anything that can be run on a stand-alone operating system can be served as a SaaS or Platform as a Service (PaaS) service, e.g.:
- Authentication and Authorization – LDAP, Directory, and Kerberos services.
- File Transfer – SAMBA, NFS, FTP, SFTP, HTTP, WebDav, etc.
- File Storage – SAMBA, NFS, etc.
- Database – Clustered databases such as Oracle RAC or MySQL Cluster – or even as database services – like those used by web hosting companies.
- Auditing – should be part of the applications it is required for.
- and countless others…
What about security? Rather than using operating system-wide security, your security model should be implemented at every necessary tier of your application stack, whether you’re on a Cloud architecture or not.
Then, there’s SOA (Service Oriented Architecture) which was/is a poplar trend. SOA concepts and Cloud Computing can fit very nicely together for both Cloud providers and customers. Metered services in a SOA can be great for both as well (per use, by volume, etc.). The value-add in this sort of situation (SaaS, PaaS, etc.) is the ability to orchestrate cloud services, as building blocks, to provide a cohesive end product/service.