Scaling best practices

In this section, we will go through some of the best practices that applications should implement to take advantages of scalability capability provided by VMSS.

Prefer scaling out

Scaling out is a better scaling solution compared to scaling up. Scaling up or down means re-sizing of virtual machine instances. When a virtual machine is resized, it generally needs to be restarted, which has its own disadvantages. First, there is a downtime for the machine. Second, if there are active users connected to the application on that instance, they might face unavailability of application or they might even have lost transactions. Scaling out does not impact existing virtual machines. It provisions newer machines and adds them to the group.

Bare metal versus dormant instances

Scaling new instances can take two broad approaches. Either create the new instance from scratch, which means to install applications, configure, and test, while on the other hand, there can be dormant instances...