sample mongodb setup - create user for db dbname with admin access

gistfile1.txt

use admin;

// create superuser
db.createUser({user: "username", pwd: "PLAINTEXTPASSWORD", roles: ["userAdminAnyDatabase"]});

// create oplog user
db.createUser({user: "oplogger", pwd: "PLAINTEXTPASSWORD", roles: [{role: "read", db: "local"}]})

// create user for another database
use foo;
db.createUser({user: "username", pwd: "PLAINTEXTPASSWORD", roles: ["readWrite"]});

// set engine to mmapv1, unbind, add replica set
vi /etc/mongod.conf
storage:
  engine: mmapv1
net:
  port: 27017
  #bindIp: 127.0.0.1
replication:
   replSetName: rs0
   
// initiate replica set from mongo cli
rs.initiate()

// restart mongo. if issues connecting, clear out log file and restart
sudo rm -f /var/log/mongodb/mongod.log
sudo touch /var/log/mongodb/mongod.log
sudo chown mongodb:mongodb /var/log/mongodb/mongod.log

// setup keyfile
sudo mkdir /opt/mongodb
sudo openssl rand -base64 741 > /opt/mongodb/mongodb-keyfile
sudo chown mongodb:mongodb /opt/mongodb/mongodb-keyfile
sudo chmod 600 /opt/mongodb/mongodb-keyfile

// update config
sudo vi /etc/mongodb.conf
// uncomment and update security keyFile with: /opt/mongodb/mongodb-keyfile