Resources

1. Installation

For UBUNTU 14.x

Install git

• https://www.digitalocean.com/community/tutorials/how-to-install-git-on-ubuntu-14-04

Install pip

• https://www.liquidweb.com/kb/how-to-install-pip-on-ubuntu-14-04-lts/

For UBUNTU 16.x

Install pip

• sudo apt-get install python-pip

Upgrade Celery

• sudo pip install --upgrade celery

2. Problems with MongoDB

Start MongoDB on boot

• https://www.howtoforge.com/tutorial/install-mongodb-on-ubuntu-16.04/
• If MongoDB could not be started with sudo service mongod start:

** 1. sudo netstat -lpn | grep :27017 ;list the running mongo process

    tcp   0   0 0.0.0.0:27017   0.0.0.0:* LISTEN 11598/mongod    ;Example output

** 2. sudo kill -9 PID ; ex. 11598

** 3. sudo mongod --fork --dbpath /var/lib/mongodb --smallfiles --logpath /var/log/mongodb.log --logappend --config /etc/mongod.conf

Limit Preferences

• https://docs.mongodb.com/manual/reference/ulimit/
• http://serverfault.com/questions/626978/mongodb-error-out-of-file-descriptors-waiting-one-second-before-trying-to-acc

Unclean Shutdown

• If the service is terminated, crashed or whatever reasons, the lock file will not be removed and so we have to remove it manually before starting the service
• sudo rm /var/lib/mongodb/mongod.lock
• Sometimes you will also need to manually remove a port file
• sudo rm /tmp/mongodb-27017.sock

3. Problems with MongoDB Authentication

• Make sure MongoDB uses schema 3
  • db.system.version.save({ "_id" : "authSchema", "currentVersion" : 3 })
• Then create a new user
  • db.createUser({user: USERNAME, pwd: PWD, roles: [{role: "root", db: "admin"}]})
• Enable the authentication
  • Edit the config file: sudo pico /etc/mongod.conf
  • Uncomment:
    • security: authorization: enabled
  • Restart the service: sudo service mongod restart