How to create a Docker image

Image vs Container?

Docker images provide the instructions and ingredients, while Docker containers are the actual running applications built from those instructions.

Key differences

• Function An image is a template, a container is a running instance.
• Mutability Images are read-only, containers are writable. Changes in a container won't affect the original image.
• Lifespan Images are meant to be shared and reused, containers are typically created and destroyed as needed.

List

• Docker Official Images
• Verified Publisher

How to create a docker image

Create a Dockerfile

# syntax=docker/dockerfile:1

# specify the base image to  be used for the application, alpine or ubuntu

FROM golang:1.22-alpine

# create a working directory inside the image

WORKDIR /app

# copy directory files i.e all files ending with .go

COPY . ./

# compile application

RUN go build -o ./ASCII-art-web && apk add --no-cache bash
# tells Docker that the container listens on specified network ports at runtime

EXPOSE 8080

# command to be used to execute when the image is used to start a container

CMD [ "/ASCII-art-web" ]

build the image

sudo docker build --tag ascii-art-web .

sudo docker build --tag ascii_web .

check if image is created

sudo docker images

How to create and launch a container from the Image

Commands

sudo docker container run -p 8080:8080 --detach --name <container_name> <image>

note: you can change the port to 0:8080 to ask to your kernel to handle the attribution of the port. Handy in a script when you don't know if your user port 8080 is free.

stop a container

sudo docker stop <container_name>

remove a container

sudo docker rm <container_name>

remove an image

sudo docker rmi <image>