title: can't start mongodb when open auth on mongod.conf
body: <p>i can't start mongod when i uncomment "security:authorization:enabled" options on /etc/mongod.conf ?
  on mongodb 3.4.2
  on centos6.5;</p>
  
  <p>this is the commond print out :</p>
  
  <pre><code>sudo service mongod restart
  Stopping mongod:                                           [  OK  ]
  Starting mongod:                                           [FAILED]
  </code></pre>
  
  <p>this is my mongod.conf file:
  here is the commond print out :</p>
  
  <pre><code># mongod.conf
  
  # for documentation of all options, see:
  #   http://docs.mongodb.org/manual/reference/configuration-options/
  
  # where to write logging data.
  systemLog:
    destination: file
    logAppend: true
    path: /var/log/mongodb/mongod.log
  
  # Where and how to store data.
  storage:
    dbPath: /var/lib/mongo
    journal:
      enabled: true
  #  engine:
  #  mmapv1:
  #  wiredTiger:
  
  # how the process runs
  processManagement:
    fork: true  # fork and run in background
    pidFilePath: /var/run/mongodb/mongod.pid  # location of pidfile
  
  # network interfaces
  net:
    port: 58018
    bindIp: 127.0.0.1  # Listen to local interface only, comment to listen on all interfaces.
  
  #security:                &lt;---uncomment here will start failed
  #  authorization:enabled  &lt;---uncomment here will start failed
  #operationProfiling:
  
  #replication:
  
  #sharding:
  
  ## Enterprise-Only Options
  
  #auditLog:
  
  #snmp:
  </code></pre>