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Docker Examples

Lists images available on the local machine

docker image ls

To get a specific image

docker image pull <imagename>

docker image pull python:3.12-slim

To inspect the downloaded image

docker image inspect python:3.12-slim

Check the architecture, ports open etc..

Create a container

docker create \
    --name edge-http \
    -p 8000:8000 \
    python:3.12-slim \
    python -m http.server

List the Image and container again

Start the container

docker start edge-http

Open browser and check http://localhost:8000 shows the docker internal file structure.

docker inspect edge-http

Shows all running containers

docker container ls

Shows all containers

docker container ls -a

Disk usage by images, containers, volumes

docker system df

Logs Inspection

docker logs edge-http
docker inspect edge-http

Stop and remove

docker stop edge-http
docker rm edge-http

docker run is a wrapper for docker pull, docker create, docker start

Run an MQTT Broker

MQTT broker typically runs at edge or cloud.

Create a new container

docker run -d \
  --name mqtt-broker \
  -p 1883:1883 \
  eclipse-mosquitto:2.0

Verify

docker container ls
docker logs mqtt-broker

Stop and Delete

docker stop mqtt-broker
docker rm mqtt-broker

Deploy MySQL Database using Containers

Create the following folder

Linux / Mac

mkdir -p container/mysql
cd container/mysql

Windows

md container
cd container
md mysql
cd mysql
mkdir data

Note: If you already have MySQL Server installed in your machine then please change the port to 3307 as given below.

-p 3307:3306 \

Run the container


docker run --name mysql -d \
    -p 3306:3306 \
    -e MYSQL_ROOT_PASSWORD=root-pwd \
    -e MYSQL_ROOT_HOST="%" \
    -e MYSQL_DATABASE=mydb \
    -e MYSQL_USER=remote_user \
    -e MYSQL_PASSWORD=remote_user-pwd \
    -v ./data:/var/lib/mysql \
    docker.io/library/mysql:8.4.4

-d : detached (background mode) -p : 3306:3306 maps mysql default port 3306 to host machines port 3306 3307:3306 maps mysql default port 3306 to host machines port 3307

-e MYSQL_ROOT_HOST=“%” Allows to login to MySQL using MySQL Workbench

docker exec -it mysql bash

CREATE DATABASE IF NOT EXISTS iot_telemetry;
USE iot_telemetry;

CREATE TABLE telemetry (
  id BIGINT AUTO_INCREMENT PRIMARY KEY,
  device_id VARCHAR(64),
  temperature_c FLOAT,
  humidity_pct FLOAT,
  event_ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

INSERT INTO telemetry (device_id, temperature_c, humidity_pct)
VALUES
('esp32-001', 24.1, 51.2),
('esp32-002', 23.4, 49.8);

SELECT * FROM telemetry;

List all the Containers

docker container ls -a

Stop MySQL Container

docker stop mysql

Delete the container**

docker rm mysql

Build your own Image


mkdir -p container
cd container

Calculator Example

Follow the README.md

Fork & Clone

git clone https://github.com/gchandra10/docker_mycalc_demo.git

Docker Compose

Docker Compose is a tool that lets you define and run multi-container Docker applications using a single YAML file.

Instead of manually running multiple docker run commands, you describe:

Services (containers)
Networks
Volumes
Environment variables
Dependencies between services

…all inside a docker-compose.yml file.

Sample docker-compose.yaml

version: "3.9"

services:
  app:
    build: .
    ports:
      - "5000:5000"
    depends_on:
      - db

  db:
    image: postgres:15
    environment:
      POSTGRES_PASSWORD: example

docker compose up -d

docker compose down

Usecases

Reproducible environments
Clean dev setups
Ideal for microservices
Great for IoT stacks like broker + processor + DB

MQTT Python Docker Compose Example

https://github.com/gchandra10/docker-compose-mqtt-demo

Web App Demo

Fork & Clone

git clone https://github.com/gchandra10/docker_webapp_demo.git

Publish Image to Docker Hub

Create a Repository “my_faker_calc”
Under Account Settings
- Personal Access Token
- Create a PAT token with Read/Write access for 1 day

Replace gchandra10 with yours.

docker login

enter userid
enter PAT token

Then build the Image with your userid

docker build -t gchandra10/my_faker_calc:1.0 .
docker image ls

Copy the ImageID of gchandra10/my_fake_calc:1.0

Tag the ImageID with necessary version and latest

docker image tag <image_id> gchandra10/my_faker_calc:latest

Push the Images to Docker Hub (version and latest)

docker push gchandra10/my_faker_calc:1.0 
docker push gchandra10/my_faker_calc:latest

Image Security

Trivy

Open Source Scanner.

https://trivy.dev/latest/getting-started/installation/

trivy image python:3.12-slim

# Focus on high risk only

trivy image --severity HIGH,CRITICAL python:3.12-slim

# Show only fixes available
trivy image --ignore-unfixed false python:3.12-slim

trivy image gchandra10/my_faker_calc

trivy image gchandra10/my_faker_calc --severity CRITICAL,HIGH --format table

trivy image gchandra10/my_faker_calc --severity CRITICAL,HIGH  --output result.txt

Grype

Open Source Scanner

grype python:3.12-slim

Common Mitigation Rules

Upgrade the base
- move to newer version of python if 3.12 has issues
Minimize OS packages
- check our how many layers of packages are installed
Pin versions on libraries
- requirements.txt make sure Library versions are pinned for easy detection
Run as non-root
- Create local user instead of running as root
Don’t share Secrets
- dont copy .env or any secrets in your script or application.

#docker #container #dockerhubVer 6.0.23

Adv - IoT Upper Stack