title: Ceph configuration file and ceph-deploy
body: <p>I set up a test cluster and follow the <a href="http://docs.ceph.com/docs/master/start/quick-ceph-deploy/" rel="nofollow noreferrer">documentation</a>.</p>
  
  <p>I created cluster with command <code>ceph-deploy new node1</code>. After that, ceph configuration file appeared in the current directory, which contains information about the monitor on the node with hostname <code>node1</code>. Then I added two OSDs to the cluster.</p>
  
  <p>So now I have cluster with 1 monitor and 2 OSDs. <code>ceph status</code> command says that status is <code>HEALTH_OK</code>.</p>
  
  <p>Following all the same documentation, I moved on to section "Expanding your cluster" and added two new monitors with commands <code>ceph-deploy mon add node2</code> and <code>ceph-deploy mon add node3</code>. Now I have cluster with three monitors in the quorum and status <code>HEALTH_OK</code>, but there is one little discrepancy for me. The <code>ceph.conf</code> is still the same. It contains old information about only one monitor. Why <code>ceph-deploy mon add {node-name}</code> command didn't update configuration file? And the main question is why <code>ceph status</code> displays correct information about new cluster state with 3 monitors while <code>ceph.conf</code> doesn't contain this information. Where is real configuration file and why <code>ceph-deploy</code> knows it but I don't?</p>
  
  <p>And it works even after a reboot. All ceph daemons start, read incorrect <code>ceph.conf</code> (I checked this with <code>strace</code>) and, ignoring this, work fine with new configuration.</p>
  
  <p>And the last question. Why <code>ceph-deploy osd activate {ceph-node}:/path/to/directory</code> command didn't update configuration file too? After all why do we need <code>ceph.conf</code> file if we have so smart <code>ceph-deploy</code> now?</p>