Docker compose is a (centralised) tool to manage (define and run) multi-containers Docker applications in 1 isolated environment.

To define and manage services

So they run together in isolated environment

Easy to run and clean up our entire app

Prerequisite: Docker Postrequisite: Kubernetes (K8s)

This note is a cohesive walkthrough based on the crash course I watched (YouTube video), the hands-on custom docker compose project (prasanth-ntu/docker-compose-crash-course/), and the corresponding custom image for JS application pushed to the Docker Hub (## prasanthntu/my-app).

Docker Compose Architecture: End-to-End

Open in new tab (*Note: Best viewed in desktop or landscape view*)

`docker compose.yaml` configuration

Simplifies container management

✅ Helps to structure our commands.
- With a single command, we create and start all the services from our configurations.
✅ Easier to make changes, and see current configuration.
- We use a single YAML file to configure and maintain our application’s services.
✅ Declarative definition approach.
- Defining the current state.

Network configuration

✅ By default, Compose sets up a single network for our app.
✅ Communication via container name.
✅ We have option to specify our own networks with top-level “network” keys.

Control Startup Order

Some services depend on other services (e.g., mongo-express depending on mongo-db, webapp that needs to connect to db).
depends_on attribute controls the order of service startup and shutdown.

Demo

Demo Without Compose

We achieve everything with plain docker commands.

Step 1 - Create the Docker Network

Docker network = Allows containers to communicate with each other and with the external world

$ docker network ls 
 
NETWORK ID     NAME      DRIVER    SCOPE
76e60ffb24f0   bridge    bridge    local
e5fe30e3c7da   host      host      local
412bd0cd1370   none      null      local

Create a user-defined network using docker network create [OPTIONS] NETWORK_NAME.

$ misc docker network create mongo-network   
fec1b2d064db058e2087e243eb85b90b9a16630bc7b27c0bab09c1a245b5361f
 
$ docker network ls 
 
NETWORK ID     NAME            DRIVER    SCOPE
76e60ffb24f0   bridge          bridge    local
e5fe30e3c7da   host            host      local
fec1b2d064db   mongo-network   bridge    local
412bd0cd1370   none            null      local

Containers connected to mongo-network can resolve each other by name.

Step 2 - Start MongoDB Container

Docker Hub > Official Images > mongo
- Default MongoDB port: 27017
- Environment variables:
  - MONGO_INITDB_ROOT_USERNAME -
  - MONGO_INITDB_ROOT_PASSWORD -

Fetch/pull the mongoDB docker image and run it in detached mode.

# start mongodb
$ docker run -d \
-p 27017:27017 \
-e MONGO_INITDB_ROOT_USERNAME=admin \
-e MONGO_INITDB_ROOT_PASSWORD=supersecret \
--network mongo-network \
--name mongodb \
mongo
 
Unable to find image 'mongo:latest' locally
latest: Pulling from library/mongo
e4ff4183d396: Pull complete 
97dd3f0ce510: Pull complete 
be6c93d4528b: Pull complete 
3ab158345587: Pull complete 
fe1d960a6567: Pull complete 
cec3fd50f49f: Pull complete 
90aac4a84565: Pull complete 
bdb9ad4997b8: Pull complete 
fce2d6033e18: Download complete 
2ce8f7b034ed: Download complete 
Digest: sha256:7f5bbdafebde7c42e42e33396d01c0eda3eb753da8dae99071a30e350568a0a4
Status: Downloaded newer image for mongo:latest
045ac74aff2b4407cd9579768c10c105043fe19ebac6024ef52f7af1b828a6ad

$ docker ps      
CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS          PORTS                                             NAMES
045ac74aff2b   mongo     "docker-entrypoint.s…"   19 seconds ago   Up 18 seconds   0.0.0.0:27017->27017/tcp, [::]:27017->27017/tcp   mongodb

Step 3 - Start Mongo Express Container

Docker >Hub Official Images > mongo-express
- Default Express port: 8081
- Environment variables:
  - ME_CONFIG_MONGODB_ADMINUSERNAME - MongoDB admin username
  - ME_CONFIG_MONGODB_ADMINPASSWORD - MongoDB admin password
  - ME_CONFIG_MONGODB_SERVER - MongoDB container name. Use comma delimited list of host names for replica sets.

Fetch/pull the mongo-express docker image and run it.

# start mongo-express
$ 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

$ docker ps      
 
  CONTAINER ID   IMAGE           COMMAND                  CREATED          STATUS          PORTS                                             NAMES
ade494422af5   mongo-express   "/sbin/tini -- /dock…"   13 seconds ago   Up 13 seconds   0.0.0.0:8081->8081/tcp, [::]:8081->8081/tcp       mongo-express
d5a8c56f2dd7   mongo           "docker-entrypoint.s…"   3 minutes ago    Up 3 minutes    0.0.0.0:27017->27017/tcp, [::]:27017->27017/tcp   mongodb

Retrieve the mongo-express web login creds

$ docker logs -f mongo-express 
 
Waiting for mongo:27017...
/docker-entrypoint.sh: line 15: mongo: Name does not resolve
/docker-entrypoint.sh: line 15: /dev/tcp/mongo/27017: Invalid argument
...
Welcome to mongo-express 1.0.2
------------------------
 
 
Mongo Express server listening at http://0.0.0.0:8081
Server is open to allow connections from anyone (0.0.0.0)
basicAuth credentials are "admin:pass", it is recommended you change this in your config.js

Visit http://localhost:8081/ and enter the login creds retrieved from the logs

username: admin
password: pass

🥳 We are able to connect to the MongoDB using Mongo Express

Demo With Compose

Step 1 - Map docker commands to compose definition

docker-compose.yaml

services: # List all our services we want to run
 
  mongodb: # First service (container name of the service)
  # configs for the service
    image: mongo # Image to use for the service
    ports: # List of ports to expose
      - 27017:27017 # Map the port 27017 on the host to the port 27017 on the container
    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

Step 2 - Create and start containers

Official documentation

Go through docker-compose.yaml and start all the docker container services configured in it.

# Builds, (re)creates, starts, and attaches to containers for a service.
$ docker compose -f docker-compose.yaml up
 
...
[+] Running 3/3
 ✔ Network docker-compose-demo_default            Created                                                                                                                                                    0.0s 
 ✔ Container docker-compose-demo-mongo-express-1  Created                                                                                                                                                    0.0s 
 ✔ Container docker-compose-demo-mongodb-1        Created                                                                                                                                                    0.0s 
Attaching to mongo-express-1, mongodb-1
...
mongo-express-1  | Mongo Express server listening at http://0.0.0.0:8081
mongo-express-1  | Server is open to allow connections from anyone (0.0.0.0)
mongo-express-1  | basicAuth credentials are "admin:pass", it is recommended you change this in your config.js!
mongodb-1        | {"t":{"$date":"2025-12-25T11:06:57.313+00:00"},"s":"I",  "c":"NETWORK",  "id":22943,   "ctx":"listener","msg":"Connection accepted","attr":{"remote":"172.18.0.3:52368","isLoadBalanced":false,"uuid":{"uuid":{"$uuid":"7c957071-43ce-479d-88c0-7adf35250adc"}},"connectionId":3,"connectionCount":3}}
mongodb-1        | {"t":{"$date":"2025-12-25T11:06:57.314+00:00"},"s":"I",  "c":"NETWORK",  "id":51800,   "ctx":"conn3","msg":"client metadata","attr":{"remote":"172.18.0.3:52368","client":"conn3","negotiatedCompressors":[],"doc":{"driver":{"name":"nodejs","version":"4.13.0"},"os":{"type":"Linux","name":"linux","architecture":"arm64","version":"6.12.54-linuxkit"},"platform":"Node.js v18.20.3, LE (unified)|Node.js v18.20.3, LE (unified)"}}}
...

compose up aggregates the output of each container.

So, the logs of the two containers mongodb-1 and mongo-express-1 are mixed.

Docker container names follow <folder_name>-<service-name>-<id>.

$ docker ps      
  
CONTAINER ID   IMAGE           COMMAND                  CREATED         STATUS         PORTS                                             NAMES
c783f9de70f9   mongo           "docker-entrypoint.s…"   2 minutes ago   Up 2 minutes   0.0.0.0:27017->27017/tcp, [::]:27017->27017/tcp   docker-compose-demo-mongodb-1
ca8f40bbda1a   mongo-express   "/sbin/tini -- /dock…"   2 minutes ago   Up 2 minutes   0.0.0.0:8081->8081/tcp, [::]:8081->8081/tcp       docker-compose-demo-mongo-express-1

Docker compose takes care of creating dedicated network for all the containers (refer docker-compose-demo_default network).

$ docker network ls
 
NETWORK ID     NAME                          DRIVER    SCOPE
44928d6c7344   bridge                        bridge    local
8681bc4c5af8   docker-compose-demo_default   bridge    local
e5fe30e3c7da   host                          host      local
412bd0cd1370   none                          null      local

Visit http://localhost:8081/ and enter the login creds retrieved from the logs

username: admin
password: pass

Create a new db and table

Create my-db DB
Inside the my-db, create my-collection collection

Run docker compose in the background

$ docker compose -f docker-compose.yaml up -d
[+] Running 2/2
 ✔ Container docker-compose-demo-mongodb-1        Started                                                                                                                                                    0.1s 
 ✔ Container docker-compose-demo-mongo-express-1  Started

Easy way to stop (and completely remove) all the containers, networks, volumes and images created by “up” ⟹ All the changes made to the db will be gone as containers are ephemeral.

$ docker compose -f docker-compose.yaml down 
[+] Running 3/3
 ✔ Container docker-compose-demo-mongo-express-1  Removed                                                                                                                                                    0.2s 
 ✔ Container docker-compose-demo-mongodb-1        Removed                                                                                                                                                    0.3s 
 ✔ Network docker-compose-demo_default            Removed

To stop and re-start the containers only (without completely removing them) ⟹ Will keep the data

$docker compose -f docker-compose.yaml stop 
[+] Stopping 2/2
 ✔ Container docker-compose-demo-mongo-express-1  Stopped                                                                                                                                                    0.2s 
 ✔ Container docker-compose-demo-mongodb-1        Stopped   
 
$ docker compose -f docker-compose.yaml start
[+] Running 2/2
 ✔ Container docker-compose-demo-mongodb-1        Started                                                                                                                                                    0.1s 
 ✔ Container docker-compose-demo-mongo-express-1  Started

Step 3 - Add own custom web application

Git repo: https://gitlab.com/twn-youtube/docker-compose-crash-course

Add “New Document” in the my-collection with below details:

{
        "_id": ObjectId(),
    	"myid": 1,
    	"data": "some dynamic data loaded from mongodb"
}

After adding, it would look something like this

What we will do now

Let’s create a custom JS application that
- Connects to the mongo db
- Displays the retrieved data
Containerize the JS application with Dockerfile
Run it as part of the docker compose services using docker-compose.yaml

Clone the repo

$ git clone https://gitlab.com/twn-youtube/docker-compose-crash-course                                               
Cloning into 'docker-compose-crash-course'...
warning: redirecting to https://gitlab.com/twn-youtube/docker-compose-crash-course.git/
remote: Enumerating objects: 12, done.
remote: Total 12 (delta 0), reused 0 (delta 0), pack-reused 12 (from 1)
Receiving objects: 100% (12/12), 19.01 KiB | 19.01 MiB/s, done.

Project Tree

|- app
	|- server.js # Connects to the DB logic
	|- index.html # Shows 2 lines of data (1. static hardcoded, 2. dynamic from MongoDB)
	|- package.json
|- Dockerfile
|- docker-compose-v1.yaml

We don't have to worry about understanding the actual code as our focus is on the configuration and dockerization.

Update the yaml file.

Run docker compose to start all our services.

$ docker compose -f docker-compose-v1.yaml up -d                               
[+] Building 14.4s (13/13) FINISHED                                                                                                                                                                               
 => [internal] load local bake definitions                                                                                                                                                                   0.0s
 => => reading from stdin 599B                                                                                                                                                                               0.0s
 => [internal] load build definition from Dockerfile                                                                                                                                                         0.0s
 => => transferring dockerfile: 551B                                                                                                                                                                         0.0s
 => [internal] load metadata for docker.io/library/node:20-alpine                                                                                                                                            4.2s
 => [auth] library/node:pull token for registry-1.docker.io                                                                                                                                                  0.0s
 => [internal] load .dockerignore                                                                                                                                                                            0.0s
 => => transferring context: 2B                                                                                                                                                                              0.0s
 => [1/5] FROM docker.io/library/node:20-alpine@sha256:658d0f63e501824d6c23e06d4bb95c71e7d704537c9d9272f488ac03a370d448                                                                                      5.4s
 => => resolve docker.io/library/node:20-alpine@sha256:658d0f63e501824d6c23e06d4bb95c71e7d704537c9d9272f488ac03a370d448                                                                                      0.0s
 => => sha256:bb9f6f8b202047f37f5d51a1f2e731b60925a601fe4c9c1495e6c000ddd25944 1.26MB / 1.26MB                                                                                                               1.0s
 => => sha256:70268380327fbc2d9c066979d554cdff4c22f752e9be70bde123ec5ccb64c292 443B / 443B                                                                                                                   0.6s
 => => sha256:eb9824d7990580162dd96cf3c8e08c9e966ed8d819adbb6e065c3c5ab73d74b4 43.12MB / 43.12MB                                                                                                             4.8s
 => => extracting sha256:eb9824d7990580162dd96cf3c8e08c9e966ed8d819adbb6e065c3c5ab73d74b4                                                                                                                    0.6s
 => => extracting sha256:bb9f6f8b202047f37f5d51a1f2e731b60925a601fe4c9c1495e6c000ddd25944                                                                                                                    0.0s
 => => extracting sha256:70268380327fbc2d9c066979d554cdff4c22f752e9be70bde123ec5ccb64c292                                                                                                                    0.0s
 => [internal] load build context                                                                                                                                                                            0.0s
 => => transferring context: 79.97kB                                                                                                                                                                         0.0s
 => [2/5] RUN mkdir -p /home/app                                                                                                                                                                             0.3s
 => [3/5] COPY ./app /home/app                                                                                                                                                                               0.0s
 => [4/5] WORKDIR /home/app                                                                                                                                                                                  0.0s
 => [5/5] RUN npm install                                                                                                                                                                                    3.1s
 => exporting to image                                                                                                                                                                                       1.0s 
 => => exporting layers                                                                                                                                                                                      0.6s 
 => => exporting manifest sha256:8309693daec8852b51aab55da903df788f891c9815ca3b7da07bd12d32a53825                                                                                                            0.0s 
 => => exporting config sha256:9c1b48bebea1dd7c80915825f2bb9ca7efb4be17071c688b8a875c99c445b3d9                                                                                                              0.0s
 => => exporting attestation manifest sha256:7d3a9651efd8f15d76d9f8fe2c938a4ccdff1021efa86795055b9a5cc7326270                                                                                                0.0s
 => => exporting manifest list sha256:46ac1d0db873ba307f412e7ef79ad7f10156416c3971fd5b22aae8307aa03fd2                                                                                                       0.0s
 => => naming to docker.io/library/docker-compose-crash-course-my-app:latest                                                                                                                                 0.0s
 => => unpacking to docker.io/library/docker-compose-crash-course-my-app:latest                                                                                                                              0.3s
 => resolving provenance for metadata file                                                                                                                                                                   0.0s
[+] Running 5/5
 ✔ docker-compose-crash-course-my-app                     Built                                                                                                                                              0.0s 
 ✔ Network docker-compose-crash-course_default            Created                                                                                                                                            0.0s 
 ✔ Container docker-compose-crash-course-my-app-1         Started                                                                                                                                            0.4s 
 ✔ Container docker-compose-crash-course-mongodb-1        Started                                                                                                                                            0.4s 
 ✔ Container docker-compose-crash-course-mongo-express-1  Started

Visit http://localhost:3000/ and we will observe this

$ docker ps                                     
CONTAINER ID   IMAGE                                COMMAND                  CREATED              STATUS              PORTS                                             NAMES
d938cb321665   mongo-express                        "/sbin/tini -- /dock…"   About a minute ago   Up About a minute   0.0.0.0:8081->8081/tcp, [::]:8081->8081/tcp       docker-compose-crash-course-mongo-express-1
002bd3e0ba3a   mongo                                "docker-entrypoint.s…"   About a minute ago   Up About a minute   0.0.0.0:27017->27017/tcp, [::]:27017->27017/tcp   docker-compose-crash-course-mongodb-1
789e177f4333   docker-compose-crash-course-my-app   "docker-entrypoint.s…"   About a minute ago   Up About a minute   0.0.0.0:3000->3000/tcp, [::]:3000->3000/tcp       docker-compose-crash-course-my-app-1

$ docker ps -a
CONTAINER ID   IMAGE                                COMMAND                  CREATED              STATUS                       PORTS                                             NAMES
d938cb321665   mongo-express                        "/sbin/tini -- /dock…"   About a minute ago   Up About a minute            0.0.0.0:8081->8081/tcp, [::]:8081->8081/tcp       docker-compose-crash-course-mongo-express-1
002bd3e0ba3a   mongo                                "docker-entrypoint.s…"   About a minute ago   Up About a minute            0.0.0.0:27017->27017/tcp, [::]:27017->27017/tcp   docker-compose-crash-course-mongodb-1
789e177f4333   docker-compose-crash-course-my-app   "docker-entrypoint.s…"   About a minute ago   Up About a minute            0.0.0.0:3000->3000/tcp, [::]:3000->3000/tcp       docker-compose-crash-course-my-app-1
979c5d68491d   mongo-express                        "/sbin/tini -- /dock…"   2 hours ago          Exited (143) 2 minutes ago                                                     docker-compose-demo-mongo-express-1
5929b55898a1   mongo                                "docker-entrypoint.s…"   2 hours ago          Exited (0) 2 minutes ago                                                       docker-compose-demo-mongodb-1

From the above results, we can see that the previous container services

docker-compose-demo-mongodb-1 and
docker-compose-demo-mongo-express-1 are not running.

Instead, new container services

docker-compose-crash-course-mongodb-1,
docker-compose-crash-course-mongo-express-1, and
docker-compose-crash-course-my-app-1 are created from scratch.

Let’s override the value that’s used as a prefix (say, we want to reuse the containers but moved the docker-compose.yaml to a different project folder/location).

# Remove the newly created containers
$ docker compose -f docker-compose-v1.yaml down 
[+] Running 4/4
 ✔ Container docker-compose-crash-course-mongo-express-1  Removed                                                                                                                                            0.3s 
 ✔ Container docker-compose-crash-course-my-app-1         Removed                                                                                                                                            1.2s 
 ✔ Container docker-compose-crash-course-mongodb-1        Removed                                                                                                                                            0.3s 
 ✔ Network docker-compose-crash-course_default            Removed     
 
# 
$ docker compose --project-name docker-compose-demo -f docker-compose-v1.yaml up -d
...
[+] Running 4/4
 ✔ docker-compose-demo-my-app                     Built                                                                                                                                                      0.0s 
 ✔ Container docker-compose-demo-my-app-1         Started                                                                                                                                                    0.2s 
 ✔ Container docker-compose-demo-mongodb-1        Started                                                                                                                                                    0.2s 
 ✔ Container docker-compose-demo-mongo-express-1  Started

From the above output, we can observe that old instances of docker-compose-demo-mongodb-1 and docker-compose-demo-mongo-express-1 are restarted instead of new ones being created.

So, if we refresh, we will still have my-db and my-collection, and the data inside in it.

Visit http://localhost:3000/ and we will observe this (both static and dynamic data)

Here’s the Network results, esp. the fetch-data results

$ curl -s http://localhost:3000/fetch-data 
{"_id":"694d85017720d490d5f09da1","myid":1,"data":"some dynamic data loaded from mongodb"}%

To stop (and remove) all the services,

$ docker compose --project-name docker-compose-demo -f docker-compose-v1.yaml down
[+] Running 4/4
 ✔ Container docker-compose-demo-my-app-1         Removed                                                                                                                                                    1.2s 
 ✔ Container docker-compose-demo-mongo-express-1  Removed                                                                                                                                                    0.2s 
 ✔ Container docker-compose-demo-mongodb-1        Removed                                                                                                                                                    0.2s 
 ✔ Network docker-compose-demo_default            Removed                                                                                                                                                    0.2s 
 
$ docker ps                                                                      
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES

Variables in `docker-compose.yaml`

Do NOT hardcode any sensitive data, esp username, passwords, tokens, secret keys, etc.

Update the docker-compose.yaml file by replacing hardcoded ENV variables with placeholders.

Then, export these environment variables in the shell.

$ echo $MONGO_ADMIN_USER               
 
 
$ export MONGO_ADMIN_USER=admin
 
$ export MONGO_ADMIN_PASS=supersecret          
 
$ echo $MONGO_ADMIN_USER       
admin
 
$ echo $MONGO_ADMIN_PASS  
supersecret

# Run the docker compose to start the build and service
$ docker compose --project-name docker-compose-demo -f docker-compose-v2.yaml up 
[+] Running 4/4
 ✔ Network docker-compose-demo_default            Created                                                                                                                                                    0.0s 
 ✔ Container docker-compose-demo-my-app-1         Created                                                                                                                                                    0.0s 
 ✔ Container docker-compose-demo-mongodb-1        Created                                                                                                                                                    0.1s 
 ✔ Container docker-compose-demo-mongo-express-1  Created                                                                                                                                                    0.1s 
Attaching to mongo-express-1, mongodb-1, my-app-1
...

# Stop the container service (but do not remove it)
$ $ docker compose --project-name docker-compose-demo -f docker-compose-v2.yaml stop
 
# (Re-)Start the service
$ docker compose --project-name docker-compose-demo -f docker-compose-v2.yaml start

Use `secrets` in `docker-compose.yaml`

With environment variables, there is still a risk of unintentional information exposure.

secrets is an even better way to use secrets without having to use environment variables.
- 1. Define the secret using the top-level secrets element.
- 1. In the service definition, reference the secret with the secrets attribute.
This permits granular access control within a service container via standard filesystem permissions.

# Secrets example
services:
	myapp:
		image: myapp:latest
		secrets: 
			- my_secret
			  
secrts:
	my_secret
		file: ./my_secret.txt

Push to repository & Pull from it (Public or Private)

Create a new repo in your docker account

Namespace: prasanthntu
Repository Name: my-app

Build our image using docker file

# Build our image using "docker build" command 
$ docker build -t prasanthntu/my-app:1.0 .
[+] Building 2.9s (11/11) FINISHED                                                                                                                                                           docker:desktop-linux
 => [internal] load build definition from Dockerfile                                                                                                                                                         0.0s
 => => transferring dockerfile: 551B                                                                                                                                                                         0.0s
 => [internal] load metadata for docker.io/library/node:20-alpine                                                                                                                                            2.7s
 => [auth] library/node:pull token for registry-1.docker.io                                                                                                                                                  0.0s
 => [internal] load .dockerignore                                                                                                                                                                            0.0s
 => => transferring context: 2B                                                                                                                                                                              0.0s
 => [1/5] FROM docker.io/library/node:20-alpine@sha256:658d0f63e501824d6c23e06d4bb95c71e7d704537c9d9272f488ac03a370d448                                                                                      0.0s
 => => resolve docker.io/library/node:20-alpine@sha256:658d0f63e501824d6c23e06d4bb95c71e7d704537c9d9272f488ac03a370d448                                                                                      0.0s
 => [internal] load build context                                                                                                                                                                            0.0s
 => => transferring context: 170B                                                                                                                                                                            0.0s
 => CACHED [2/5] RUN mkdir -p /home/app                                                                                                                                                                      0.0s
 => CACHED [3/5] COPY ./app /home/app                                                                                                                                                                        0.0s
 => CACHED [4/5] WORKDIR /home/app                                                                                                                                                                           0.0s
 => CACHED [5/5] RUN npm install                                                                                                                                                                             0.0s
 => exporting to image                                                                                                                                                                                       0.1s
 => => exporting layers                                                                                                                                                                                      0.0s
 => => exporting manifest sha256:cb7bf027253cf5e6590db1d1c4469f43bc177014ee9a6fd12294abef6aa03323                                                                                                            0.0s
 => => exporting config sha256:a7d8f4f3b0f1523de7d0cb41b83eb16a623e48322d19c5092d5fa461dc76363b                                                                                                              0.0s
 => => exporting attestation manifest sha256:147f5f94745c90d51456656000d3e761ab48b7a3a067cccf7029322f38bae292                                                                                                0.0s
 => => exporting manifest list sha256:7905293d827c3947ee40648377bdb62404bf5cb83c2afc6978210920c5f384d9                                                                                                       0.0s
 => => naming to docker.io/prasanthntu/my-app:1.0                                                                                                                                                            0.0s
 => => unpacking to docker.io/prasanthntu/my-app:1.0                                                                                                                                                         0.0s
 
View build details: docker-desktop://dashboard/build/desktop-linux/desktop-linux/mbpw4z5gartqe0ouw85kx5ox1

$ docker login                            
Authenticating with existing credentials... [Username: prasanthntu]
 
i Info → To login with a different account, run 'docker logout' followed by 'docker login'
 
 
Login Succeeded

Push the new tag to the repository

$ docker push prasanthntu/my-app:1.0    
The push refers to repository [docker.io/prasanthntu/my-app]
46544c70f387: Pushed 
bb9f6f8b2020: Pushed 
f6b4fb944634: Pushed 
5144ef3ea83f: Pushed 
70268380327f: Pushed 
eb9824d79905: Pushed 
2bbed94c184c: Pushed 
4f4fb700ef54: Mounted from opensearchproject/opensearch-dashboards 
ea93af6352ec: Pushed 
1.0: digest: sha256:589a4da7779488b24168c6469bd5b5be0da6016f4e022661f584cf6747a287e0 size: 856

Update the docker-compose.yaml file by commenting out build: . and add image: prasanthntu/my-app:1.0 to reference our custom image in our docker repo.

Pull the image from repository and run

$ docker compose --project-name docker-compose-demo -f docker-compose-v3.yaml up -d
[+] Running 6/6
 ✔ my-app Pulled                                                                                                                                                                                             8.2s 
   ✔ 5144ef3ea83f Pull complete                                                                                                                                                                              0.0s 
   ✔ 4f4fb700ef54 Pull complete                                                                                                                                                                              0.0s 
   ✔ 2bbed94c184c Pull complete                                                                                                                                                                              0.0s 
   ✔ 46544c70f387 Pull complete                                                                                                                                                                              0.4s 
   ✔ ea93af6352ec Download complete                                                                                                                                                                          0.0s 
[+] Running 3/3
 ✔ Container docker-compose-demo-my-app-1         Started                                                                                                                                                    0.3s 
 ✔ Container docker-compose-demo-mongodb-1        Started                                                                                                                                                    0.1s 
 ✔ Container docker-compose-demo-mongo-express-1  Started

Limitations of docker compose

A lot of operational effort to run containers on a large scale.

Only well-suited for local development and small-scale deployments (i.e., if we have smaller set of containers)
Designed to run containers on a single host system
Engineers still need to operate the containers manually

Kubernetes to the Rescue

With kubernetes, we can merge hundreds of servers into one huge server to deploy all the containers that belong to same app in the environment.

Can manage large-scale apps and containers deployed across multiple nodes
Auto-Scaling
Self-Healing

Docker & Kubernetes - Strengths and Use Cases

Docker: Simplifies local development, testing and for smaller deployments.

Kubernetes: Advanced features for scalability, high availability and production-grade deployments.

Thangavel PrasanthTP

Explorer

Docker Compose

Docker Compose Architecture: End-to-End

`docker compose.yaml` configuration

Network configuration

Control Startup Order

Demo

Demo Without Compose

Step 1 - Create the Docker Network

Step 2 - Start MongoDB Container

Step 3 - Start Mongo Express Container

Demo With Compose

Step 1 - Map docker commands to compose definition

Step 2 - Create and start containers

Step 3 - Add own custom web application

What we will do now

Variables in `docker-compose.yaml`

Use `secrets` in `docker-compose.yaml`

Push to repository & Pull from it (Public or Private)

Limitations of docker compose

Kubernetes to the Rescue

Graph View

Table of Contents

Backlinks

Thangavel PrasanthTP

Explorer

Docker Compose

Docker Compose Architecture: End-to-End

docker compose.yaml configuration

Network configuration

Control Startup Order

Demo

Demo Without Compose

Step 1 - Create the Docker Network

Step 2 - Start MongoDB Container

Step 3 - Start Mongo Express Container

Demo With Compose

Step 1 - Map docker commands to compose definition

Step 2 - Create and start containers

Step 3 - Add own custom web application

What we will do now

Variables in docker-compose.yaml

Use secrets in docker-compose.yaml

Push to repository & Pull from it (Public or Private)

Limitations of docker compose

Kubernetes to the Rescue

Graph View

Table of Contents

Backlinks

`docker compose.yaml` configuration

Variables in `docker-compose.yaml`

Use `secrets` in `docker-compose.yaml`