Setting environment variables for ASP.NET Core apps in a Helm chart

In the previous post I described the .NET solution that we're deploying. It consists of two applications, TestApp.Api which is a default ASP.NET Core web API project, and a TestApp.Service which is an empty web project. The TestApp.Service represents a "headless" service, that would be handling messages from an event queue using something like NServiceBus or MassTransit.