title: mongoDB : Authentication of user is working fine, but getting "Unauthorized not authorized on admin to execute command" in the logs
body: <p>I've followed the steps as mentioned in <a href="https://stackoverflow.com/questions/23003391/how-do-i-add-an-admin-user-to-mongo-in-2-6">How do I add an admin user to Mongo in 2.6?</a></p>
  
  <p>At first, "auth=true" in the /etc/mongod.conf file is commented out so that authentication is not done and I could create the following users in respective dbs. </p>
  
  <p>Admin: </p>
  
  <pre><code>use admin;
  db.createUser({user: "mongoRoot", pwd: "password", roles: [{role: "root", db: "admin"}]}); 
  db.createUser({user: "mongoAdmin", pwd: "password", roles: ["readWrite"]});
  db.createUser({user: "siteUserAdmin", pwd: "password", roles: [{role: "userAdminAnyDatabase", db: "admin"}]}); 
  db.createUser({user: "mongoDBAdmin", pwd: "password", roles: [{role: "dbAdmin", db: "admin"}]}); 
  db.createUser({user: "mongoDBOwner", pwd: "password", roles: [{role: "dbOwner", db: "admin"}]}); 
  
  db.createUser({user: "mongoWrite", pwd: "password", roles: [{role: "readWrite",db: "mongo_database"}]});  (Added in admin so that by giving the command from the command-line 'mongo mongo_database --port 27018 -u mongoWrite -p password --authenticationDatabase admin', the user mongoWrite is able to login as done in https://gist.github.com/tamoyal/10441108)
  db.createUser({user: "mongoRead", pwd: "password", roles: [{role: "read", db: "mongo_database"}]});  (Added in admin so that by giving the command from the command-line 'mongo mongo_database --port 27018 -u mongoRead -p password --authenticationDatabase admin', the user mongoRead is able to login  as done in https://gist.github.com/tamoyal/10441108)
  </code></pre>
  
  <p>Config: </p>
  
  <pre><code>use config;
  db.createUser({user: "mongoConfig", pwd: "password", roles: [{role: "readWrite", db: "config"}]}); 
  </code></pre>
  
  <p>Test: </p>
  
  <pre><code>use test;
  db.createUser({user: "mongoTest", pwd: "password", roles: [{role: "readWrite", db: "test"}]}); 
  </code></pre>
  
  <p>mongo_database: </p>
  
  <pre><code>use mongo_database;
  db.createUser({user: "mongoWrite", pwd: "password", roles: [{role: "readWrite",db: "mongo_database"}]}); 
  db.createUser({user: "mongoRead", pwd: "password", roles: [{role: "read", db: "mongo_database"}]}); 
  db.createUser({user: "mongoAdmin", pwd: "password", roles: [{role: "readWrite", db: "mongo_database"}]}); 
  </code></pre>
  
  <p>After making sure that all the required users are added, turning on the authentication by uncommenting "auth=true" in the /etc/mongod.conf file and restarting the mongodb.</p>
  
  <pre><code>[ec2-user@ip-xxx-xx-xx-xx ~]$ mongo mongo_database --port 27018 -u mongoWrite -p password --authenticationDatabase admin
  MongoDB shell version: 2.6.10
  connecting to: 127.0.0.1:27018/mongo_database
  rs0:PRIMARY&gt; db.test.insert({"Hello":"World"});
  WriteResult({ "nInserted" : 1 })
  rs0:PRIMARY&gt; exit
  bye
  [ec2-user@ip-xxx-xx-xx-xx ~]$ mongo mongo_database --port 27018 -u mongoRead -p password --authenticationDatabase admin
  MongoDB shell version: 2.6.10
  connecting to: 127.0.0.1:27018/mongo_database
  rs0:PRIMARY&gt; db.test.insert({"Hello":"World"});
  WriteResult({
          "writeError" : {
                  "code" : 13,
                  "errmsg" : "not authorized on mongo_database to execute command { insert: \"test\", documents: [ { _id: ObjectId('559bba6ead81843e121c5ac7'), Hello: \"World\" } ], ordered: true }"
          }
  })
  rs0:PRIMARY&gt;
  </code></pre>
  
  <p>Everything works fine till this point. The only issue that am encountering is that my log file is getting bombarded with the following 2 lines at almost tens of thousand lines per minute and within no time, my disk is running out of space.</p>
  
  <pre><code>2015-07-07T11:40:28.340+0000 [conn3] Unauthorized not authorized on admin to execute command { writebacklisten: ObjectId('55913d82b47aa336e4f971c2') }
  2015-07-07T11:40:28.340+0000 [conn2] Unauthorized not authorized on admin to execute command { writebacklisten: ObjectId('55923232e292bbe6ca406e4e') }
  </code></pre>
  
  <p>Just to give an idea, in a span of 10 seconds, 10 MB worth of log file is generated consisting of just the above mentioned 2 lines.</p>
  
  <pre><code>[ec2-user@ip-xxx-xx-xx-xx ~]$ date
  Tue Jul  7 11:44:01 UTC 2015
  [ec2-user@ip-xxx-xx-xx-xx ~]$ df -h
  Filesystem      Size  Used Avail Use% Mounted on
  /dev/xvdh       4.8G  388M  4.2G   9% /log
  [ec2-user@ip-xxx-xx-xx-xx ~]$ date
  Tue Jul  7 11:44:14 UTC 2015
  [ec2-user@ip-xxx-xx-xx-xx ~]$ df -h
  Filesystem      Size  Used Avail Use% Mounted on
  /dev/xvdh       4.8G  398M  4.2G   9% /log
  </code></pre>
  
  <p>To my knowledge, the authentication seems to be working fine. Just that the logs are getting filled at super sonic speed. What am I doing wrong? Please help. Thanks In Advance.</p>