Virtual machine High Availability

Virtual machines provide compute capabilities. It provides processing power and hosting for applications and services. If the application is deployed on a single virtual machine and that machine is down, then even the application is not available. If the application is composed of multiple tiers and each tier is deployed in its own single instance of a virtual machine, even a downtime in a single virtual machine can render the application non-available.  Although Azure tries to make even single virtual machine deployments highly available by placing on different racks as soon as it can figure out, Azure does not ensure or guarantee any SLA on them. Azure provides SLA for those virtual machines that are grouped together in an availability set. It provides 5 nines (99.999%) SLA for the availability of virtual machines if they are part of an availability set and more than two virtual machines are on that availability set.