Docker basics

Start your first container

docker run busybox echo Welcome to SoftwareCircus

That's it, thanks for your attention. Please consult Container Solutions for more informations or insert another coin!

We used a small and simple image busybox and ran a single process echo

More useful container:

docker run -it ubuntu /bin/bash

Install something inside the container e.g.: apt-get update && apt-get install -y figlet

Run:

figlet hello

Exit this container and execute again:

docker run -it ubuntu /bin/bash
figlet hello

Figlet is missing

Make that change persistent:

docker run -it ubuntu /bin/bash
apt-get update && apt-get install -y figlet

If you have started an interactive container (with option -it), you can detach from it.

The "detach" sequence is ^P^Q. Or you can detach by killing the Docker client. Don’t hit ^C, as this would deliver SIGINT to the container

docker commit <yourContainerId> <newImageId>

Find out your container ID with docker ps

Test it docker run -ti figlet and then execute figlet hello

List running containers

docker ps

To see only the last container that was started

docker ps -l

To see only the ID of containers

docker ps -q

This also works in combination

docker ps -ql

Dockerfile overview

A Dockerfile is a build recipe for a Docker image.

It contains a series of instructions telling Docker how an image is constructed.
The docker build command builds an image from a Dockerfile.

Copy this into your editor of choice:

FROM ubuntu
RUN apt-get update
RUN apt-get install -y figlet

Build the image

docker build -t figlet .

-t indicates that a tag will be applied and . is the default location to store the image

Test it docker run -ti figlet and then execute figlet hello