DISCLAIMER: Image is generated using FREE version of ChatGPT.
Setup
For this post, we will need docker.
Let’s quickly set up the environment and verify the installation.
$ sudo apt update
$ sudo apt install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
$ sudo usermod -aG docker $USER
Verify the installation:
$ docker --version
Docker version 28.0.1, build 068a01e
Edward J. Sabol, on Facebook reminded me that if I am using recent version of docker then I can use the compose sub-command of the docker also in my examples.
Honestly speaking this was news to me, I had no clue if it was existed.
All I knew was docker-compose, standalone tool for managing multi-container Docker applications.
Just for fun, I am using the docker compose command in this post.
Having said, this will also work with docker-compose without any change.
Introduction
docker-compose
- It is commonly referred as
Compose V1. - It is Python-based tool.
- It needs separate installation e.g. sudo apt install docker-compose.
- It is slower comparative to ‘docker compose’.
docker compose
- It is referred as
Compose V2. - It is Go-based tool.
- It is integrated with Docker CLI since Docker v20.10.0.
- It is much faster than ‘docker-compose’.
There is a stackoverflow post that goes into the details, if you are interested.
This is what I have on my box:
$ docker compose version
Docker Compose version v2.33.1
$ docker-compose version
docker-compose version 1.29.2, build unknown
docker-py version: 5.0.3
CPython version: 3.12.3
OpenSSL version: OpenSSL 3.0.13 30 Jan 2024
I have created an alias dps for the command docker ps, as shown below:
$ alias dps='docker ps --format "Container ID: {{.ID}}\nImage: {{.Image}}\nCommand: {{.Command}}\nCreated: {{.CreatedAt}}\nStatus: {{.Status}}\nPorts: {{.Ports}}\nNames: {{.Names}}\n"'
For this demo, I am going to use the latest MongoDB and Mongo Express images.
Plan
The goal is to create a container running Mongo Express, linked to a MongoDB container.
We will start with a simple straight forward approach using just docker command.
Create a Docker Network
First, let’s create a docker network named: mongo-network
$ docker network create mongo-network
7ca8d14845c684336d8e494515670675a8685646455e3761a0e88b0ff4e3234e
$ docker network ls
NETWORK ID NAME DRIVER SCOPE
1240c8ea9eb8 bridge bridge local
d0b60d358dfb host host local
7ca8d14845c6 mongo-network bridge local
Create the MongoDB Container
Next, We will create a MongoDB container:
$ docker run -d \
-p 27017:27017 \
-e MONGO_INITDB_ROOT_USERNAME=admin \
-e MONGO_INITDB_ROOT_PASSWORD=supersecret \
--network mongo-network \
--name mongodb \
mongo
048833d02f2693bf7bae641611cc466698fb5857b6503ef5743054e9a5518a31
Create the Mongo Express Container
Now, we will create the Mongo Express container.
$ docker run -d \
-p 8081:8081 \
-e ME_CONFIG_MONGODB_ADMINUSERNAME=admin \
-e ME_CONFIG_MONGODB_ADMINPASSWORD=supersecret \
-e ME_CONFIG_MONGODB_SERVER=mongodb \
--network mongo-network \
--name mongo-express \
mongo-express
a82c59ffbee01f0b1d466b747e8288846c1e11f187205e10fddc6637f864c878
Verify Containers
Check the status of both containers:
$ dps
Container ID: a82c59ffbee0
Image: mongo-express
Command: "/sbin/tini -- /dock…"
Created: 2025-03-20 19:14:21 +0000 GMT
Status: Up About a minute
Ports: 0.0.0.0:8081->8081/tcp, [::]:8081->8081/tcp
Names: mongo-express
Container ID: 048833d02f26
Image: mongo
Command: "docker-entrypoint.s…"
Created: 2025-03-20 19:11:09 +0000 GMT
Status: Up 4 minutes
Ports: 0.0.0.0:27017->27017/tcp, [::]:27017->27017/tcp
Names: mongodb
Mongo Express should be accessible at http://localhost:8081 using the credential admin/pass.
Observations
I found this process tedious and time consuming.
Imagine if you had to create multiple containers manually, it would quickly become a nightmare.
Docker Compose
To make your life easy and comfortable, docker compose, comes into the picture.
Advantages of Docker Compose
-
Define and manage multiple containers in a single file.
-
Handles dependenciesy efficiently e.g., MongoDB starts before Mongo Express.
-
Automatically creates a network for all containers.
-
No need to remember long commands for running containers.
Cleanup
Let’s stop and remove both containers including the network, so that we have a clean setup.
$ docker stop mongodb mongo-express
$ docker rm mongodb mongo-express
$ docker network rm mongo-network
Re-creating MongoDB and Mongo Express containers using docker compose.
First, we will create the configuration file: docker-compose.yml
version: '3.8'
services:
mongodb:
image: mongo
ports:
- 27017:27017
environment:
- MONGO_INITDB_ROOT_USERNAME=admin
- MONGO_INITDB_ROOT_PASSWORD=supersecret
mongo-express:
image: mongo-express
ports:
- 8081:8081
environment:
- ME_CONFIG_MONGODB_ADMINUSERNAME=admin
- ME_CONFIG_MONGODB_ADMINPASSWORD=supersecret
- ME_CONFIG_MONGODB_SERVER=mongodb
depends_on:
- "mongodb"
That’s it all, we need.
To start the containers, simply run one command:
$ docker compose up -d
✔ Network docker-compose_default Created 0.1s
✔ Container docker-compose-mongodb-1 Started 0.3s
✔ Container docker-compose-mongo-express-1 Started 0.3s
Did you notice, it automatically created the network for us!
Let’s verify the status of both containers:
$ dps
Container ID: 4bfd8ccc3715
Image: mongo
Command: "docker-entrypoint.s…"
Created: 2025-03-20 19:32:20 +0000 GMT
Status: Up About a minute
Ports: 0.0.0.0:27017->27017/tcp, [::]:27017->27017/tcp
Names: docker-compose_mongodb_1
Container ID: 2d34f54091b6
Image: mongo-express
Command: "/sbin/tini -- /dock…"
Created: 2025-03-20 19:32:20 +0000 GMT
Status: Up About a minute
Ports: 0.0.0.0:8081->8081/tcp, [::]:8081->8081/tcp
Names: docker-compose_mongo-express_1
Mongo Express is still accessible at: http://localhost:8081
To stop both the containers, simply run one command:
$ docker compose down
✔ Container docker-compose-mongodb-1 Removed 0.7s
✔ Container docker-compose-mongo-express-1 Removed 0.9s
✔ Network docker-compose_default Removed 0.6s
Conclusion
Isn’t it much simpler and easier to manage?
This is just the tip of the iceberg when it comes to docker compose.
Keep Hacking !!