Deploy MongoDB as a Docker container

Introduction

One of the most accessible NoSQL databases, MongoDB®, has many available deployment options. In this post, I use Docker® to deploy MongoDB as a container and use the shell client to interact with that container.

After you install Docker on your computer or server, perform the following steps
to deploy MongoDB as a Docker container:

1. Download the latest or a specific MongoDB Docker image.
2. Deploy an instance of MongoDB as a container.
3. Interact with the MongoDB Docker container with basic shell operations.

Download the MongoDB Docker image

If you have Docker installed on your computer or server, you can get the MongoDB image from the Docker Hub container registry. Be sure to download the specific image version that you expect to use, such as mongo:4.0.4. You don't have to specify the image version, but if you omit it, you get the most current version, which could result in an inconsistent experience because Mongo can update the latest version at any time.

Executing the `docker images` command gives a list of images available on the server. In our case, it shows the MongoDB image with the tag 4.0.4 available for use.

Use the following commands to download the MongoDB image and list your available images:

    # docker pull mongo:4.0.4
    # docker images

Deploy an instance of MongoDB as a container 

Start the container in detached, `-d`, mode. Because containers use ephemeralstorage, you should mount a volume, `-v`, to retain the data by providing the local path, /data/db. This path is the container's internal directory. This action preserves the data on the host's /data/db path even when you stop or remove the container. In the command, you provide a name, `--name`, for your container followed by the Docker image and a tag. In this case, I used mongo:4.0.4 for the tag. The command returns a string with the container's ID. The docker `ps` command shows a list of running containers.

    # docker run -d -v /data/db:/data/db --name mymongo mongo:4.0.4
    # docker ps

Interact with the MongoDB Docker container with the shell 

To take advantage of a functional MongoDB deployment, you can interact with the database by using the shell client. Because you are running the container in detached mode, you should connect by using the interactive terminal. Use the following command to connect to your deployment, named mymongo, and start the bash shell:

# docker exec -it mymongo bash
 

To launch the MongoDB shell client, run the following command:

    # mongo 

From the MongoDB shell client, you can access all the functions outlined in the MongoDB documentation. For example, you can see what databases exist in your instance with the following command: 

 > show dbs

 Conclusion

In this post, I created a MongoDB container by using Docker with an attached storage volume from a host system to a container. I also showed you how to start interacting with the MongoDB Docker container through the shell. The post offers a basic demonstration of running a MongoDB instance in a Docker container, but you can use the same MongoDB image to build any number of containers. Use those containers to create replica sets and do much more to create a robust containerized application.

I hope this post helped you to get a general understanding of how to get a MongoDB instance up and running and start working with it in minutes.