Leveraging deployment slots
The first thing to know about deployment slots is that they are live apps with hostnames, content, and configuration settings. In a common modern development workflow, you’d deploy code through whatever means to a non-production deployment slot (often called staging, although this could be any name and there may be multiple slots between that and production) to test and validate. From there, you may start increasing the percentage of traffic that gets routed to the staging slot or you may just swap the slots – whatever was in production goes to staging and whatever was in staging goes to production, with no downtime.
Because it is just a swap, if something unexpected does happen as a result, you can swap the slots back and everything would return to before the swap occurred. Several actions take place during a swap, including the routing rules changing once all the slots have warmed up. There’s a documentation link in the Further...
