I'm having hard times with the application's release process. The app is being developed in .NET Core and uses 'appsettings.json' that holds connection string to a database. The app should be deployed to Kubernetes cluster in Azure. We have a build and release processes in Azure DevOps so the process is automated, although the problem belongs to a necessity to deploy the same to multiple environments (DEV/QA/UAT) and every env is using its own database. When we build Docker image, the 'appsettings.json' that holds a connection string is being baked-in to the image. The next step pushes the image to a container repository which Release process then uses to deploy the image to a cluster (the steps are classics).

Replacing or putting the connection parameters into the variables on the build step is not a big deal. However, this is a Release process that controls the deployment to multiple environments. I don't see how I can substitute the connection string to a database in the Release pipeline... or better to say, how to deploy to three different environments with database connection string properly set for each of them.

Please suggest how it can be achieved. The only option I came up with is having three separate build pipelines for every env which doesn't look pretty. The entire idea behind Release is that you can manage the approval process before rolling out the changes to the next environment.