title: Run azure devops pipeline on every available pool
body: <p>I'm evaluating Azure Devops and want to have following workflow: I want to have a pipeline build and run it on our self-hosted build agent, but if non them is available I want to fall back on hosted agent and vice versa. According to documentation <a href="https://docs.microsoft.com/en-us/azure/devops/pipelines/agents/agents?view=azure-devops" rel="nofollow noreferrer">https://docs.microsoft.com/en-us/azure/devops/pipelines/agents/agents?view=azure-devops</a> in the yaml file you need to define in which pool will job run. </p>
  
  <p>Can I have a pipeline build without having to define a pool/define many pools as fallback?</p>