MongoDB

The short version:

Stop wasting your time with these idiotic esoteric database configurations where 99% of it works perfectly but the one critical component (authentication) has some sloppy documentation.

Just use docker.

https://git.charlesreid1.com/docker/d-mongodb

https://git.charlesreid1.com/docker/d-mongoexpress

Summary

The brief summary:

• MongoDB provides a nosql unstructured data store for arbitrarily complicated json structures
• Listens on port 27017
• Install from mongodb.org debian repos
• Config handles file paths, logging, security, networking
• Multiple ways to interface (command line shell in Javascript, or via language bindings)
• Users must be created per-database, or a system-wide admin account added
• Enable user access controls, expose to private management LAN interfaces

Installing

Native Installation

MongoDB/Manual Installation - installing MongoDB manually/natively on the OS

Docker Installation

To run MongoDB using Docker, I recommend using a docker-pod that has both MongoDB and MongoExpress (web frontend for MongoDB).

Links:

• https://git.charlesreid1.com/docker/pod-mongo - docker pod that uses docker containers defined in the repos below to run the docker pod
• https://git.charlesreid1.com/docker/d-mongodb - docker container to run MongoDB
• https://git.charlesreid1.com/docker/d-mongoexpress - docker container to run MongoExpress

MongoDB/Docker - installing/running MongoDB in a docker pod

Configuring

MongoDB/Configuration - notes on configuring MongoDB

MongoDB documentation on configuration: https://docs.mongodb.com/manual/reference/configuration-options/

Startup Service

MongoDB/Startup - notes on creating a MongoDB startup service

Create Users and Enable Authentication

It is a good idea to set up users and user authentication to control access to the data in the database.

To create a system-wide mongodb user admin, create a user with the role userAdminAnyDatabase (no other roles!).

Start the mongo shell from localhost (which will not require authentication to begin with) or using --noauth flag by using the mongo command:

$ mongo
> 

Now create a user for the admin database (run these commands directly in the shell). This will create a user "darthvader" with password "secretpass":

> use admin
> db.createUser(
  {
    user: "darthvader",
    pwd: "secretpass",
    roles: [ { role: "userAdminAnyDatabase", db: "admin" } ]
  }
)

Now you can enable client access control.

As per the mongodb documentation [1], to enable authorization you can either pass --auth when starting mongod or you can set security.authorization in the mongodb config file as follows:

security:
    authorization: enabled

List Users

Start up the mongo shell and tell it to use the admin database. Then use the show users command:

> use admin
> show users
{
	"_id" : "admin.admin",
	"user" : "admin",
	"db" : "admin",
	"roles" : [
		{
			"role" : "userAdminAnyDatabase",
			"db" : "admin"
		}
	]
}

Drop Users

To drop users:

> db.dropUser('admin')
true

Selecting an Interface

The first thing you have to decide before interacting with the database is how you want to interact.

The mongodb shell is a javascript shell that can be used from a command line on the mongodb server.

Mongodb also has python language bindings. there are multiple non-mongo-provided third party APIs and libraries too, so there are multiple options.

Basic CRUD Operations

MongoDB performs CRUD (create, read, update, delete) transactions/operations on the data that it stores.

Mongo/CRUD

Basic Collections Operations

Basic operations on collections:

Mongo/Collections

Basic Database Operations

Notes on basic database operations:

Mongo/Databases

Monitoring

MongoDB as a Monitoring Target

MongoDB has several mechanisms for monitoring the state of the database (per second operations, cache sizes, disk and memory usage, etc.)

Utilities like Netdata and Collectd have plugins written for MongoDB that can collect this information as part of scraping the system status.

MongoDB as a Monitoring Data Store

collectd has a Write_MongoDB plugin to allow collectd to write its data to MongoDB.

Plugin link: https://collectd.org/wiki/index.php/Plugin:Write_MongoDB

APIs

Python API: Pymongo

Java API: MongoDB/Java

References

pymodm: https://pymodm.readthedocs.io/en/latest/getting-started.html

Database design patterns: https://docs.mongodb.com/manual/applications/data-models/

Cheat sheet: https://blog.codecentric.de/files/2012/12/MongoDB-CheatSheet-v1_0.pdf

Related Page

• MongoExpress