title: Difference between the commands "gcloud compute ssh" and "ssh"
body: <p>What exactly is the difference between the <code>gcloud compute ssh</code> comannd and "just" the  <code>ssh</code> command?</p>
  
  <p>I made the observation that even so I can easily connect between two instances using <code>gcloud compute ssh</code>, i cannot do it with the <code>ssh</code> command. However, after setting up the ssh-keys manually, the ssh command works fine. But shouldn't the gcloud command handle the key management? And if it is set up one time using gcloud, why is the ssh command not working properly</p>
  
  <p>.</p>
  
  <p>Works fine:</p>
  
  <pre><code>gcloud compute ssh instance_2
  gcloud compute shh instance_1
  </code></pre>
  
  <p>.</p>
  
  <p>Doesn't work without manually setting up the ssh-keys:</p>
  
  <pre><code>ssh instance_2
  shh instance_1
  </code></pre>
  
  <p>.</p>
  
  <p>This question comes from a different problem I had, which drove me nuts for days: <a href="https://stackoverflow.com/questions/35819556/openmpi-permission-denied-error-while-trying-to-use-mpirun">OpenMPI: Permission denied error while trying to use mpirun</a></p>