For Infrastructure as a Service, you need to manage all the operating system dependencies, your runtime and application needs. You also need to set up the network between the virtual machines (VM) and the load balancing between different data centers (cloud provider) to create a highly available system.

Container as a Service does not require you to manage all OS dependencies of the VM. Instead, the cloud provider provides an OS environment in which you can run your containers. These containers contain all the dependencies needed for the runtime and the application.

For Platform as a Service, the runtime is provided by the cloud provider. They will install all the OS dependencies needed for the delivered version of the runtime and you can focus on building the application that runs at the chosen runtime. (Such a runtime can be IIS for C#, Tomcat for Java or Express for Node.JS).

For Function as a Service, the included runtime is not a web application server, but the runtime needed to execute the code in the programming language of your choice (Java, Node.JS, C# ...). The difference with PaaS is that you do not have to configure the scalability.

#REST #GraphQL