I have decided to re-invest my spare time (spare == few precious idle periods) to try and catch up with the exciting technology advances happening all around us. In this series, which I refer to as Willy’s Cave Dwelling Notes, I will summarise the most important information as I dig myself through the technology strata. Enjoy, reference and most importantly share candid feedback, so that we can correct and nudge these information summaries on an ongoing basis.
… although not today’s topic, these cloud scenes over Samiahmoo bay are great 
Why cloud computing?
Cloud computing is about making computing and storage resources available as a service to users using a web browser or lightweight application. The service and user environments are abstracted, which means there is no platform dependency and that the application running as a service can benefit from infinite resources, scalability, reliability and security, not caring (usually) where the services are located.
As shown in the following illustration, the “Cloud” is the space containing the shared computing and storage services.
As an 80’s IT geek, this makes me wonder if the mainframe era is re-emerging in a different pyjama
Terminology
- On-Premises Data Center … compute/storage computing and network is located on the local premises.
- Software as a Service (SaaS) are applications running somewhere in the cloud, accessed via the internet.
Cloud Types
Figure: On-Premises | Private Cloud | Cloud Applications | Cloud Platform environments
Cloud Platforms
- Provide a cloud computing environment which can be used to host Cloud applications
- Offers browser self-service for storage, services and virtualization via the Internet
- Advantages:
- Faster deployment and upgrades
- Usage-based and “as-needed” pricing
- Less investment and risk in on-premises infrastructure
- Disadvantages:
- User trusts Service Provider in terms of availability and security
- Legislation may restrict the ability to host data off-site or out-of-country
- Examples:
Cloud Applications
- Also known as public cloud, running outside of the organization datacenter and accessed via Internet
- Software as a Service (SaaS)
- Single-Tenant Application … One customer uses a single instance of an application, 1:1 relationship.
- Multi-Tenant Application … Multiple customers share a single instance of an application, n:1 relationship.
- Advantages:
- Ditto to Cloud Platforms (see above)
- Disadvantages:
- Ditto to Cloud Platforms (see above)
- Limited extensibility and customization
- Examples
Private Cloud
- Implement IaaS (Infrastructure as a service) cloud platform in your on-premises environment, offering automated VM creation/deployment/management features.
- Offers a packaged and automated virtualization environment, reducing deployment and administrative costs.
- Kind of “drop a container in your computer room”, see http://www.haute-disponibilite.net/wp-content/uploads/2008/09/hp-pod.png for a sample image.
- Examples: