-
Infrastructure-as-a-service
This is usually when you have access to VMs and complete control over them, load balancers / virtual machines / gateways.
-
Platform-as-a-service
Uploading code that a cloud provider will run for you, no access to the underlying operating system/hardware
-
Software-as-a-service
Typically you run these services in your browser, such as Office365/Dropbox/Googledocs
The shared responsibility model will be demonstrate whether the cloud provider or the customer will have ownership/responsibility.
Software-as-a-service for example, the customer will be responsibile for the data and accounts, however the physical datacenter security will be down to the cloud provider.
With the serviceless model you don't have to select a plan such as Premium/Basic, this is since the Cloudprovider will autoscale for you. Platform-as-a-service however will require the user to select which level of compute they require, and scaling will be down to the user.
Serverless model could also result in completely free bills, this is since you're only paying for the compute used, therefore if no one was to browse your web app hosted via serverless, then the usage would be zero. The flip side to this is that you could recieve an unexpected bill should large amounts of compute be consumed due to autoscaling.
-
Public Cloud
This is the most commonly used type of cloud, as a customer you would rent hardware and compute from a company such as Microsoft. You have no real control as to who else is using hardware within the data center etc.
-
Private Cloud
This is when an organisation such as a Government wants complete control of the underlying hardware and owns physical infrastructure. They may use already owned devices or go and rent physical machines from a provider such as IBM in their own datacenter. This has the same functionality as a public cloud such as setting up virtual machines and virtual networking.
-
Hybrid Model
Combination of Public and Private cloud, this could be extending your private cloud into the public. An example may be extending a database from the private to public cloud for more compute.
- Cloud computing allows you to use Operational Expenditure rather than upfront Capital Expenditure.
- 99.99% uptime is roughly a maximum of 4 minutes downtime.