We can run tests either locally (launched from our own machine), or using a Test Controller which farms out the tests to multiple Test Agents so they can be run in parallel.

so we are planning to use 2nd option which using test controller to run tests from azure pipelines.

If We use the Multiple Agents test settings file, our tests will be run through the Test Controller. Since we choose this option, We will need to put a ConfigClient.endpoint.config file in
Ppbin, which is from azure repo. Here is the screenshot of ConfigClient.endpoint.config file

enter image description here

and this ConfigClient.endpoint.config file which points to the config service in the environment we want to test. This file will get copied down to the Test Agents and that is how each Test Agent will know which environment to run against.

can we select/parameterize the environment we give in the build for above location, if yes how?
Since we have large amount of automations tests to run we can use a Test Controller which farms out the tests to multiple Test Agents so they can be run in parallel.
Currently we have
Controller : ConrollerServer.Domain.local
Agents : Controllerserver.Domain.local through server.domain.local
so we have 12 agents

here in the code we choose controller below highlighted, can we select/parameterize controller ? if yes how?

enter image description here

I heared that it can be done using replace token, but how to achieve that, can you please example.

1.I have tried to use parameter but it did not work
2. I have tried to use replace token but not sure how to amend that task and get the desired results
3. I tried to use variables along with parameter but it did not work