Install MongoDB on macOS

Recently, I had to do a fresh install of MongoDB Community Edition on a MacBook running macOS Catalina. This post is a guide to show the steps I followed to ensure that the installation worked seamlessly and followed the requirements for installing third-party apps on Catalina.

To give more context, Apple made some changes to the way system volumes are structured in the recent OS as seen below:

With macOS Catalina, you can no longer store files or data in the read-only system volume, nor can you write to the “root” directory ( / ) from the command line, such as with Terminal.

Read more - https://support.apple.com/en-us/HT210650

MongoDB requires creating a data folder in the root directory, but with the recent OS changes, this might pose some challenges.

MongoDB Installation Steps

1. Install XCode - https://developer.apple.com/download/
2. Install Homebrew - https://brew.sh/#install
3. Tap the MongoDB Homebrew Tap

brew tap mongodb/brew

4. Install MongoDB Community Edition

brew install mongodb-community

Run MongoDB Community Edition

Create a data folder

In macOS Catalina, you would need to create the data folder in System/Volumes/Data instead of /data/db. This is because the root folder is now read-only to help prevent the accidental overwriting of critical operating system files:

sudo mkdir -p /System/Volumes/Data/data/db

Assign required permissions

sudo chown -R `id -un` /System/Volumes/Data/data/db

Run MongoDB

To run MongoDB, you could use either of the commands below:

brew services start mongodb-community // automatically runs MongoDB on system startup

Or

brew services run mongodb-community // does not run automatically on system startup

Check if MongoDB is running

Using brew services:

brew services list

Or

Searching available processes:

ps aux | grep -v grep | grep mongod

Connect and Use MongoDB

Open a new terminal window and run the command below to connect a mongo shell to the instance you started above:

mongo

If all worked properly and you were presented with the mongo prompt, then MongoDB is installed and running as expected. You can grab a chilled drink now 😀🍹.

Stop MongoDB

Use the command below to stop the MongoDB service:

brew services stop mongodb-community