pwd-demo

This repository contains links and commands for getting started with Docker.

Play With Docker

Play With Docker is an instructional website affiliated with Docker. It provides an interactive and online terminal for getting started with Docker.

Step-by-Step Instructions

Prerequisites

1. Create an account at Docker Hub
   • Do not use a password that has used elsewhere, it will be used on a public server during the demo.
2. Create a new repository called public-repo at Docker Hub
3. Login to Play With Docker
   • The terminal should appear within 10 seconds of logging in. If it doesn't, refresh the page until a prompt appears.
4. In the PWD terminal, install w3m for terminal based web browsing
   • apk update && apk add w3m

How to Copy and Paste in PWD Terminal

Copying and pasting works natively on MacOS using Command-C, ⌘ + c and Command-V, ⌘ + v. On Windows, use Control-Insert, CTRL + Insert instead of Control-C, CTRL + c and use Shift-Insert Shift + Insert instead of Control-V, CTRL + v.

Making Sure Docker is Installed

1. docker version

Running Containers

1. docker run hello-world
2. docker pull grycap/cowsay
3. docker run --name cowsay grycap/cowsay "/usr/games/cowsay" "Hello World"
4. docker run -d -p 80:80 --name hello-world tutum/hello-world
   • curl localhost
   • w3m localhost
     • w3m can be closed by hitting q key

Show Containers

1. docker ps -a

Show Images

1. docker images

Stopping and Starting Containers

1. docker stop hello-world
   • curl localhost should now fail
2. docker start hello-world

Removing Containers and Images

1. docker rm -f hello-world
   • docker rm -f $(docker ps -a -q) can be used to force remove all conainters
2. docker rmi tutum/hello-world:latest
   • docker rmi -f $(docker images -a -q) can be used to force remove all images

Building and Tagging Images

1. git clone https://github.com/HammerMeetNail/pwd-demo.git
2. cd pwd-demo
3. cat Dockerfile
4. cat app.py
5. docker build -t add:v1.0.0 .
6. docker run --rm add:v1.0.0 1 2

Entering Containers

1. docker run -it alpine:3.9 sh
   • Leave the container by typing exit to end the shell session
2. docker run -it --entrypoint sh add:v1.0.0
   • Browse around the container using common commands like cd, ls, cat
   • We can see the contents of our python app by running cat /app/app.py
   • Leave the container by typing exit to end the shell session

Using Python in a Container

1. docker run -it python:alpine sh
2. pip3 install requests
   • The container has a full installation of python3 and pip3
   • Install python packages uses pip3, ex. pip3 install requests
3. Start the interpreter using python
   • View the Zen of Python with import this
   • Import requests using import requests
4. Quit the interpreter using quit()
5. exit

Storing Images

1. docker login
2. Make not of your full repository name, ex. doconno2/public-repo
3. docker tag add:v1.0.0 {full repository name}:v1.0.0
   • Replace {full repository name} with the full name of your repository
   • Example: docker tag add:v1.0.0 doconno2/public-repo:v1.0.0
4. docker push {full repository name}:v1.0.0

Persisting Data

1. docker volume create temp
2. docker volume ls
3. docker run --rm -it -v temp:/temp alpine:3.9 sh -c 'echo "hello world" >> /temp/hello.txt'
4. docker rm -f $(docker ps -a -q)
5. docker ps -a
6. docker run --rm -it -v temp:/temp alpine:3.9 sh -c 'cat /temp/hello.txt'
7. docker volume rm temp
8. docker run --rm -it -v temp:/temp alpine:3.9 sh -c 'cat /temp/hello.txt'

Clean Up

1. docker system prune

Docker-Compose

1. docker-compose version
2. curl https://raw.githubusercontent.com/HammerMeetNail/pwd-demo/master/docker-compose.yml -O
3. cat docker-compose.yml
4. docker-compose up -d
5. curl localhost
   • w3m localhost
     • w3m can be closed by hitting q key
6. docker-compose logs cowsay-hello-world
7. docker-compose down

Kubernetes via K3s and Docker-Compose

1. cd /tmp && curl https://raw.githubusercontent.com/HammerMeetNail/pwd-demo/master/docker-compose-k3s.yml -O
2. docker-compose -f docker-compose-k3s.yml up -d
3. curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl
4. chmod +x kubectl && mv kubectl /usr/local/bin
5. kubectl --kubeconfig /tmp/kubeconfig.yaml get nodes
6. kubectl --kubeconfig /tmp/kubeconfig.yaml create deployment hello-node --image=gcr.io/hello-minikube-zero-install/hello-node
7. kubectl --kubeconfig /tmp/kubeconfig.yaml get po
8. kubectl --kubeconfig kubeconfig.yaml expose deployment hello-node --type=LoadBalancer --port=8080
9. kubectl --kubeconfig /tmp/kubeconfig.yaml get services
   • Note the External-IP for the hello-node LoadBalancer
10. curl {external ip address}:8080
    • Replace {external ip address} with External-IP for hello-node, ex. 172.20.0.2

Install Docker

Everything above should be runnable in Play-With-Docker, but if Play-With-Docker is unavailable Docker can be installed manually.

Resources

1. Play With Docker
2. Play With Kubernetes
3. K3s
4. Katacoda