Will ADF deployment using azure devops affect existing Pipelines/Jobs in the environment

Question

I am implementing azure devOps in Azure Data Factory.

My development environment ADF is integrated to a git repository.

I have created a build pipeline for building artifacts when there is a change in adf_publish branch.

My next step is to deploy the ARM template artifact to the PROD environment.

Suppose there are many triggered pipelines in the PROD environment and few pipelines were running in the PROD env at the time when the DEV changes are getting deployed to PROD.

My questions are:

1. How the changes are deployed from DevOps to PROD environment? Will it delete and replace all the pipelines and triggers from DevOps or It will pick only the changes and update the PROD env without touching the unchanged pipelines?
2. Suppose a pipeline is running in PROD env at the time of deployment, what will happen to that pipeline run?
3. Suppose there is a triggered pipeline at 3:00 O clock and deployment starts at 2:55 and ends at 3:05. What will happen to that triggered pipeline which was supposed to run at 3:00?

Any one having a clear idea about above questions or Is there any documentation for reference to obtain answers for these questions?

I have gone through Keeping deployment mode as Incremental instead of keeping it as Complete at the time of ARM template deployment. Will that option do all the tasks which I asked above?

Answer 1

How the changes are deployed from DevOps to PROD environment? Will it delete and replace all the pipelines and triggers from DevOps or It will pick only the changes and update the PROD env without touching the unchanged pipelines?

It depends on the deployment mode you choose.

• Deployment Mode: This specifies the deployment mode in which the Azure resources specified in the template have to be deployed.
  Incremental mode handles deployments as incremental updates to the
  resource group . It leaves unchanged resources that exist in the
  resource group but are not specified in the template. Complete mode
  deletes resources that are not in your template. Validate mode
  enables you to find syntactical problems with the template before
  creating actual resources. By default, incremental mode is used.

Suppose a pipeline is running in PROD env at the time of deployment, what will happen to that pipeline run?

Your deployment will fail, and you may receive a 409 conflict error message. You could check the document Best practices for CI/CD：

Pre- and post-deployment script. Before the Resource Manager deployment step in CI/CD, you need to complete certain tasks, like stopping and restarting triggers and performing cleanup. We recommend that you use PowerShell scripts before and after the deployment task. For more information, see Update active triggers. The data factory team has provided a script to use located at the bottom of this page.

Suppose there is a triggered pipeline at 3:00 O clock and deployment starts at 2:55 and ends at 3:05. What will happen to that triggered pipeline which was supposed to run at 3:00?

Similar to your second question, the pipeline should not be triggered (or in the pending state), but I still don't have an instance to test such a scenario.