Azure DevOps XDT Transform tasks allow you to build release profiles that transform the base config file with settings that are specific to each environment, such as a connection string that points to different db servers for different environments. The app.dev.config file has transformations for the dev environment, app.qa.config for qa, etc, which are applied during the deployment to the base app.config file.
I need to take this one step further and deploy custom config files for each individual server in a load balanced environment. For example, the DEV environment has two servers dev1.mysite.com and dev2.mysite.com that are load balanced by dev.mysite.com. Each of the two servers needs specific settings in the config file deployed to that server.
I don't (yet) see a way in Azure DevOps to do this. Part of the solution might be to set up variables with the setting that needs to be applied to each environment/server but I haven't figured out how to apply the correct variable to each config.
You can use task Magic Chunks to apply the variable to each config.
You can search for Magic Chunks task in your pipeline and install it to your organization. Then add Config transform task before the deployment task to update the config file with specific setting. For below example settings of magic chunk task:
As above screenshot shows, You can reference your pipeline variables in the tasks.
There are other extension tasks like RegEx Find & Replace you can use to replace the variables in the config files.