A deployment strategy, to a large extent, affects the availability of the application and overall environment. Here are the few following things you should do:
- Deploy multiple instances of Azure resources, including multiple instances for VMs, cloud services, and other resources.
- Deploy VMs on availability sets or availability zones. They cannot be used together.
- Deploy multiple instances of VMs across multiple regions.
- Create multiple environments and keep at least one of them in standby mode.