Setup with Docker

The fastest way to get a real MongoDB to play with is Docker. The official mongo image gives you a clean, isolated server in one command, with nothing installed permanently on your machine and nothing to uninstall afterwards. This lesson gets you from “Docker is running” to “I can talk to MongoDB” — first with a one-liner, then with a small docker-compose.yml you can keep in your project.

You only need Docker Desktop (or the Docker engine) installed and running. Everything else comes from the image.

A one-line docker run

This command pulls the official image, starts a container named mongo-dev, publishes the default MongoDB port 27017 to your machine, stores the data in a named volume so it survives a restart, and sets a root username and password:

docker run -d \
  --name mongo-dev \
  -p 27017:27017 \
  -v mongo-data:/data/db \
  -e MONGO_INITDB_ROOT_USERNAME=root \
  -e MONGO_INITDB_ROOT_PASSWORD=secret \
  mongo:7

A few things worth understanding in that command:

-d runs the container in the background (detached) so it does not tie up your terminal.
-p 27017:27017 maps the container’s port 27017 to the same port on your host, which is where MongoDB listens by default.
-v mongo-data:/data/db mounts a named volume at /data/db, the directory MongoDB writes its files to. The volume lives outside the container, so deleting and recreating the container does not lose your data.
-e MONGO_INITDB_ROOT_USERNAME / -e MONGO_INITDB_ROOT_PASSWORD create an administrative user the first time the container initialises an empty data directory.

A docker-compose file

For anything beyond a quick test, a docker-compose.yml is nicer: the configuration lives in a file you can commit, and a single command brings everything up. This version runs MongoDB and adds mongo-express, a lightweight web UI for poking at your data in the browser:

services:
  mongo:
    image: mongo:7
    container_name: mongo-dev
    restart: unless-stopped
    ports:
      - "27017:27017"
    environment:
      MONGO_INITDB_ROOT_USERNAME: root
      MONGO_INITDB_ROOT_PASSWORD: secret
    volumes:
      - mongo-data:/data/db

  mongo-express:
    image: mongo-express:latest
    container_name: mongo-express
    restart: unless-stopped
    ports:
      - "8081:8081"
    environment:
      ME_CONFIG_MONGODB_ADMINUSERNAME: root
      ME_CONFIG_MONGODB_ADMINPASSWORD: secret
      ME_CONFIG_MONGODB_URL: "mongodb://root:secret@mongo:27017/"
    depends_on:
      - mongo

volumes:
  mongo-data:

Bring the whole stack up from the directory that holds the file:

docker compose up -d

When it is running you can open mongo-express at http://localhost:8081 to browse databases and collections in a browser. The mongo-express service is optional — delete it if you only want the database.

How the pieces fit together

The container runs MongoDB and listens on port 27017. Your published port forwards localhost:27017 into it, the named volume keeps the data safe outside the container, and anything that speaks the MongoDB protocol — mongosh, Compass, or your application — connects through that port.

flowchart LR
  App["Your app / mongosh / Compass"] -->|"mongodb://localhost:27017"| Port["Host port 27017"]
  Port --> Container["mongo container"]
  Container -->|"writes to /data/db"| Volume["named volume: mongo-data"]

Your client connects through the published port to the container, which persists data in a named volume

Verify it is running

Check that the container is up with docker ps:

docker ps

You should see a row for the mongo image with a status of Up and the port mapping 0.0.0.0:27017->27017/tcp. Now connect with the shell. The mongosh client ships inside the image, so you can run it without installing anything:

docker exec -it mongo-dev mongosh "mongodb://root:secret@localhost:27017"

If you have mongosh installed on your host instead, point it at the published port directly:

mongosh "mongodb://localhost:27017"

A successful connection drops you at a test> prompt. From there, typing db.runCommand({ ping: 1 }) and getting back { ok: 1 } confirms the server is alive and answering.

Tips and gotchas

Data persistence lives in the volume, not the container. As long as you keep the mongo-data volume, you can stop, remove, and recreate the container without losing anything. Running docker volume rm mongo-data is what actually deletes the data.
The root user is created only on first init. The MONGO_INITDB_ROOT_* variables take effect when the data directory is empty. If you change them later against an existing volume, they are ignored — the existing user stays.
Port 27017 is the MongoDB default. If something else already uses it, change the host side of the mapping, for example -p 27018:27017, and connect to 27018.
Pin a major version like mongo:7 rather than mongo:latest so an image update does not surprise you with a different server version.