I just helped put a rather big system in production. There are always a lot of things to do and we lately turned on availability monitoring with Azure Application Insights.
Since we knew we were going to use this feature, we had added a “ping” controller to our API tier. This controller had a single method called “IsAlive”. It returns a 200 if it can access the database and a 400 if not.
5 minutes after we turned on monitoring, we were able to visualise the latency from 5 spots on the internet likely to have clients using the system. If something fails, we get alerts thrown that tell us when the system falls and when it gets back online.
Doing this a few years ago would had required specialised tools and now, it is a few clicks away in all of the major platforms. Use it, it’s five minutes to ensure you are warned if a problem arises.