Basics

Docker

Install docker

sudo apt install docker.io

Setup docker

sudo groupadd docker sudo usermod -aG docker ${USER}

Test setup

su -s ${USER}

Test docker

docker run hello-world

Images

Get the image

docker pull python
As docker shares OS kernels, it will be linux as well.

List all local images

docker images

Remove images

docker image rm

Containers

Run a container

docker run --name myPython -it python:latest /bin/bash

-it: interactive container with a terminal

docker run --name daemon -d ubuntu /bin/sh -c "while true; do echo hello world; sleep 1; done"
run a container on background

docker start myPython
run an existing container by name

Stop a container

docker stop myPython

Remove a container

docker rm myPython

List all containers

docker ps -a

Exit a container

exit

Enter into a container running in background

docker attach myPython

Volumes

A directory to be mounted to a container

Create a volume

docker volume create --name test_volume

List all volume

docker volume ls

Inspect a volume

docker volume inspect test_volume

Delete a volume

docker volume rm test_volume

Docker compose

A script of "docker run" for several containers which collabrate with each other

Install

sudo curl -L "https://github.com/docker/compose/releases/download/1.25.5/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
sudo chmod +x /usr/local/bin/docker-compose
sudo ln -s /usr/local/bin/docker-compose /usr/bin/docker-compose

Common steps:

build docker image with Dockerfile
start service with docker-compose

Keywords

services：即我们要开始定义服务，每个docker容器为一个服务。
app：这里我们定义了第一个服务，app 为其名字
build: build an image with Dockerfile in the provided path image: use directly an image expose: Expose ports WITHOUT publishing them to the host machine ports: Expose ports WITH publishing them to the host machine

Build

CONTEXT: Either a path to a directory containing a Dockerfile, or a url to a git repository. DOCKERFILE: Alternate Dockerfile. ARGS: Define environment variables

Build & start

docker-compose build: build image with predefined scripts docker-compose up -d: Create and start containers, leave them background running docker-compose up -d --build: execute the above two commands

Execute a command in a container

docker-compose exec containerName COMMAND

Stop and remove

docker-compose down -v

Examples

Docker with Nginx

Prepare a webpage, such as index.html:

Hello from Docker container!

Change this line and have a look.

run -d --name "test-nginx" -p 8080:80 -v $(pwd):/usr/share/nginx/html:ro nginx:latest -p: map host 8080 port to docker 80 port
-v: mount current directory (which contains the index.html) to /usr/share/nginx/html inside docker
visit http://127.0.0.1:8080/ from host machine

Docker with flask

More on: https://djangostars.com/blog/what-is-docker-and-how-to-use-it-with-python/

Docker with flask Ngix

https://testdriven.io/blog/dockerizing-flask-with-postgres-gunicorn-and-nginx/

limiy1/dockerlearn