Container Debugging
At times, on-call personnel may be presented with a situation in which they need to quickly access container or application crash logs. Azure does not make this an intuitive process.
Thankfully, Azure does provide a centralized location for this information...if you know where to look!
Most of our diagnostic tools will be specific to the App Service, unless you need direct DB logs. Even in that case, it is recommended to consult the App Service Logs before you proceed further, just to corroborate the symptoms you are seeing.
Sidebar menu items in Azure are affectionately known as "blades". (This may be a reference to Microsoft's fascination with sharp objects, given the "Razor" framework, "C-Sharp", etc...or, it may be a reference to the concept of blade servers. You be the judge.) To proceed, find and select the blade for "Diagnose and Solve Problems", as shown:
We have several options to choose from. For most purposes, including container crashes, "Availability and Performance" is the best place to begin.
The correct option is highlighted below:
You will be presented with a collection of tool blades along the left sidebar. "Container Issues" keeps a record of recent container crashes, and is a great place to see, at-a-glance, what may be causing the problem.
If you run into continued deployment failures for an environment, use the above process on the staging slot's App Service. The "Container Crash" blade will indicate exactly why a container is failing to start.