Azure PaaS Cloud Services are a part of the older Azure Service Manager API. Cloud services were the first Azure PaaS Service released by Microsoft.
PaaS Cloud Services consist of Web Roles, which are designed to host Web applications in IIS, and Worker Roles, which are designed for running the backend processing jobs.
Like with any PaaS offering, you do not need to manage the infrastructure or ensure high availability. You can configure the instance size and the number of instances you need deployed, and the platform will handle the provisioning.
Unlike the App Service, PaaS Cloud Services offer you limited admin access to the VMs and allow you to install custom software by running startup scripts. The underlying infrastructure, however, isn' t persistent, and a particular role instance could be re-provisioned at any time. This means that installing...