IaaS scalability

There are users who want to have complete control over the base infrastructure, platform, and application. They prefer to consume IaaS solutions compared to PaaS solutions. For such customers, when they create VMs, they are also responsible for capacity sizing and scaling. There is no out-of-the-box configuring for manual or auto scaling VMs. These customers will have to write their own automation scripts, triggers, and rules to achieve auto scaling. With VMs comes the responsibility of maintaining them as well. Patching, updating, and the upgrading of VMs is the responsibility of owners. Architects should think about both planned as well as unplanned maintenance. How these VMs should be patched, the order, grouping, and other factors must be thought through to ensure that both the scalability and availability of an application is not compromised. To help alleviate such problems, Azure provides VM scale sets as a solution.