title: Gitlab CI: running the same set of tests on several machines
body: <p>In high performance computing is crucial to have a code tested against many different architectures/compilers: from a laptop to a supercomputer. </p>
  
  <p>Assuming that we have </p>
  
  <ul>
  <li><strong><code>N</code></strong> testing machines/<strong>workers</strong> (each one running <code>gitlab-ci-runner</code>); </li>
  <li><strong><code>M</code> tests</strong>,</li>
  </ul>
  
  <p>what shall be the correct layout of <code>.gitlab-ci.yml</code> to ensure that <code>each</code> of the <code>N</code> machines runs all the tests?</p>
  
  <p>Looks to me that adding just more workers ends up in a <code>round-robin</code> like assignment of the jobs.</p>
  
  <p>Thanks for your help.</p>