knowledge-kitchen

MongoDB - Setup

Database Design

1. Overview
2. Server Setup
3. Client Setup
4. Automation
5. Conclusions

Overview

The Plan

We will outline a few ways to gain access to a MongoDB server and use a MongDB client to issue commands to the database. Our discussion will include:

• running a MongDB server locally

, remotely on NYU’s classes-mongodb database server

, and remotely using MongDB Atlas - a cloud-hosted solution.

• running a MongoDB client locally

, remotely on NYU’s i6 web server

, and using a driver with any of today’s popular programming languages

Server Setup

Choices of server

There are several easy ways to try out a MongoDB server.

• MongoDB Community Server can be downloaded and tried locally on your own machine for free.

• MongoDB Atlas is a cloud-hosted database service with a free tier for new users and small-scale applications.

• Docker image of MongoDB can be used to run a MongoDB server in a Docker container.

• NYU’s Computer Science Department hosts its own MongoDB server at class-mongodb.cims.nyu.edu:27017, which all students can access.

We will use this.

Create an account on NYU CS Department’s MongoDB server

All students will need to initialize an account on our MongoDB server using the “Class MongoDB Manager”

• enter your i6.cims.nyu.edu web server username and password. You should have received an email with that password soon after registering for the course.

• if your i6 password does not work, or you can’t find it, reset it and try a new one.

Credentials

Once logged in, the Class MongoDB Manager will show you your password for the MongoDB database server - this is different from your i6 web server password.

You will need to save the following credentials somewhere.

• database server/host - this is class-mongodb.cims.nyu.edu, port 27017
• your database name - this is the same as your NYU Net ID
• username - this is the same as your NYU Net ID
• password - this will be displayed to you by the Manager tool

Client setup

Choices of client

Once set up with a server, you must access it using a client. There are several common ways to use a MongoDB client:

• Download and install mongosh, MongoDB’s official shell client, which you can run from the command line of your own machine.

• Use a “driver” module to allow code in any popular programming language to connect to a server.

• Use ssh to remotely log into NYU CS department’s i6.cims.nyu.edu server, where a mongosh shell is already installed.

Logging into NYU CS Department’s i6 server

You will need ssh to remotely log into most servers, including the CS Department’s i6 web server.

• Mac users have ssh already installed.

• Windows users can use Git for Windows, which includes ssh within Git Bash.

The command, ssh fb1258@i6.cims.nyu.edu will remotely log in to the i6 server.

• You will be asked to enter your i6 server password.

• The password will not show up on the screen as you type it - that is absolutely normal and desireable and not a cause for concern.

Connecting to MongoDB from NYU CS Department’s i6 Web Server

Once logged into the i6 web server, you can use the mongosh (or an older version named just mongo) command line client to connect to the MongoDB database server.

• Run the command, module load mongodb-4.0 to load the MongoDB client, and then export LC_ALL=en_US.UTF-8 to set the locale, which may influence character encoding used by the database.

This command can be automatically run every time you log into the i6 web server… details here.

• Next, use the MongoDB client to connect to the database server: mongosh fb1258 --host class-mongodb.cims.nyu.edu -u fb1258 -p, where fb1258 is replaced by your own NYU Net ID.

• You will be asked to supply your MongoDB server account password… do so.

Verify that you are truly logged in

Prove to yourself that you are logged into a Javascript command-line interface to MongoDB.

• Type 1 + 1 and hit Enter.

• Did it respond with 2?

If so, you’re ready to start using your MongoDB database.

Automation

The problem: typing commands manually with every login

Every time you log into the i6 web server, you must run the module load mongodb-4.0 to load the MongoDB client before using it.

• It is possible to automatically run this command every time you log in.

• You can do this by adding this command to your i6 account’s .bashrc settings file.

The solution: .bashrc

Commands placed within the .bashrc file on UNIX and Linux machines are automatically executed every time a user begins a new shell session.

To automatically run the module load mongodb-4.0 command from the .bashrc script:

• trom the i6 command line, run the command emacs .bashrc to open up this file in the emacs text editor.

• add module load mongodb-4.0 as a line in this file… also add a line with export LC_ALL=en_US.UTF-8 to set the locale while you’re at it.

• save this file by typing Control-X and then Control-S.

• exit emacs by typing Control-X and then Control-C.

Now this command will run automatically every time you log in.

The problem: entering passwords with ssh

It is tedious to remember and enter passwords every time one logs into a remote server.

• We can automate this away with cryptographic ssh keys placed locally and on the server.

The solution: public and private SSH keys

To automatically authenticate when remotely logging in, we will first generate a pair of linked cryptographic keys locally (a public key, which you can share and a matching private key which you should keep private) and then place a copy of the public key on the server.

• run the command ssh-keygen -t rsa locally on your own machine to generate a key pair

• you will be asked where to save the keys - hit Enter to accept the default location.

• you will also be asked whether to use a password to encrypt the keys… the decision is up to you. If you decide to use a password, please remember it.

The solution: public and private SSH keys (continued)

We must now copy the public key to the server. The ssh-copy-id command can do this automatically for us.

• run the command, ssh-copy-id fb1258@i6.cims.nyu.edu, where fb1258 is replaced with your i6 web server username.

• You will be asked to enter your i6 password… do so.

Assuming the command above worked successfully, you should now be able to log into i6 by simply entering, ssh fb1258@i6.cims.nyu.edu, where fb1258 is replaced with your own username. You will no longer be asked to enter a password. Try logging out and then logging in again.

Conclusions

Thank you. Good luck.