title: How to initiate authentication for replica set - MongoDB
body: <p>There is a replica set without authentication.
  I want to create its authentication for first time.</p>
  
  <p>I do as following:</p>
  
  <pre><code>1- create [administrator user][1]
  2- restarting all member with option `auth=true`
  3- login as aadministrator to one member of replica set
  4- trying to create user "db.addUser(...)"
  </code></pre>
  
  <p>but when I want to create user, it throw exception of <code>couldn't add user: not master at src/mongo/shell/db.js:128</code> </p>
  
  <p>What should I do? is it possible initiate security in existing replica set Or I should, remove replica set and rebuild it, after setting authentication.</p>