Install and run MongoDB on macOS

Recently, I ran into an error trying to run mongodb locally on my mac. Error said cannot connect to the local server. It turned out that several steps have to be done in order to run MongoDB successfully on a mac ever since the 10.15 Catalina update. I followed the instructions in the MongoDB manual here.

To sum up:

• One time thing after installation:
  • Create data directory: sudo mkdir -p /usr/local/var/mongodb
  • Create log directory: sudo mkdir -p /usr/local/var/log/mongodb
• To start MongoDB locally every time:
  • Run mongod in one terminal using the config file: sudo mongod --config /usr/local/etc/mongod.conf. Make sure the log path and db path are in your .config file, like so:

    systemLog:
      destination: file
      path: /usr/local/var/log/mongodb/mongo.log
      logAppend: true
    storage:
      dbPath: /usr/local/var/mongodb
    

  • Open another terminal, connect to the mongod locally: mongo