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This repo aims to cover Docker details (Dockerfile, Image, Container, Commands, Volumes, Docker-Compose, Networks, Swarm, Stack) quickly, and possible example usage scenarios (HowTo: LABs) in a nutshell. Possible usage scenarios are aimed to update over time.

Keywords: Docker-Image, Dockerfile, Containerization, Docker-Compose, Docker-Volume, Docker-Network, Docker-Swarm, Service, Cheatsheet.

• LAB-01: Creating First Docker Image and Container using Docker File
• LAB-02: Binding Volume to the Different Containers
  • LAB-02.1: Binding Mount to the Container
• LAB-03: Docker-Compose File - Creating 2 Different Containers: WordPress Container depends on MySql Container
• LAB-04: Creating Docker Swarm Cluster With 5 PCs using PlayWithDocker : 3 x WordPress Containers and 1 x MySql Container using Docker-Compose File
• LAB-05: Running Docker Free Local Registry, Tagging Image, Pushing Image to the Local Registry, Pulling Image From Local Registry and Deleting Images from Local Registry
• LAB-06: Transferring Content between Host PC and Docker Container
• LAB-07: Creating Docker Container using Dockerfile to Build C++ on Ubuntu18.04
• LAB-08: Creating Docker Container using Dockerfile to Build C++ on Windows
• LAB-09: Docker Configuration (Proxy, Registry)
• Docker Commands Cheatsheet

• Motivation
  • Needs
  • Benefits
  • Problems Docker does not solve
• What is Docker?
  • Architecture
  • Installation
  • Docker Engine (Deamon, REST API, CLI)
  • Docker Registry and Docker Hub
  • Docker Command Structure
  • Docker Container
  • Docker Volumes/Bind Mounts
  • Docker Network
  • Docker Log
  • Docker Stats/Memory-CPU Limitations
  • Docker Environment Variables
  • Docker File
  • Docker Image
  • Docker Compose
  • Docker Swarm
  • Docker Stack / Docker Service
• Play With Docker
• Docker Commands Cheatsheet
• Other Useful Resources Related Docker
• References

Why should we use Docker? "Docker changed the way applications used to build and ship. It has completely revolutionized the containerization world." (Ref:ItNext)

• Installing all dependencies, setting up a new environment for SW (time-consuming every time to install environment for testing )
• We want to run our apps on different platforms (Ubuntu, Windows, Raspberry Pi).
  • Question in our mind: What if, it does not run on a different OS?
• CI/CD Integration Testing: We can handle unit testing, component testing with Jenkins. What if integration testing?
  • Extending Chain: Jenkins- Docker Image - Docker Container - Automatic testing
• Are our SW products portable to carry on different PC easily? (especially in the development & testing phase)
• Developing, testing, maintenance of code as one Monolithic App could be problematic when the app needs more features/services. It is required to convert one big monolithic app into microservices.

• NOT needed to install dependencies/SWs again & again
• Enables to run on different OS, different platforms
• Enables a consistent environment
• Enables more efficient use of system resources
• Easy to use and maintain
• Efficient use of the system resources
• Isolate SW components
• Enables faster software delivery cycles
• Containers give us instant application portability.
• Enables developers to easily pack, ship, and run any application as a lightweight, portable, self-sufficient container
• Microservice Architecture (Monolithic Apps to MicroService Architecture, e.g.Cloud Native App)

(Ref: Infoworld)

• Docker does NOT fix your security issues
• Docker does NOT turn applications magically into microservices
• Docker isn’t a substitute for virtual machines

(Ref: Infoworld)

• Docker is a tool that reduces the gap between the Development/Deployment phase of a software development cycle.
• Docker is like a VM but it has more features than VMs (no kernel, only small app and file systems, portable)
  • On Linux Kernel (2000s) two features are added (these features support Docker):
    • Namespaces: Isolate process.
    • Control Groups: Resource usage (CPU, Memory) isolation and limitation for each process.
• Without Docker, each VM consumes 30% of resources (Memory, CPU)

(Ref: Docker.com)

(Ref: docs.docker.com)

• Linux: Docker Engine
  • https://docs.docker.com/engine/install/ubuntu/
• Windows: Docker Desktop for Windows
  • WSL: Windows Subsystem for Linux,
  • WSL2: virtualization through a highly optimized subset of Hyper-V to run the kernel and distributions, better than WLS.
    • https://docs.docker.com/docker-for-windows/install/
• Mac-OS: Docker Desktop for Mac
  • https://docs.docker.com/docker-for-mac/install/

• There are mainly 3 components in the Docker Engine:
  • Server is the docker daemon named docker daemon. Creates and manages docker images, containers, networks, etc.
  • Rest API instructs docker daemon what to do.
  • Command Line Interface (CLI) is the client used to enter docker commands.

(Ref: Docker.com)

• https://hub.docker.com/

App: Running Docker Free Local Registry, Tagging Container, Pushing to Local Registry, Pulling From Local Registry and Deleting Images from Local Registry

• docker [ManagementCommand] [Command]

docker container ls -adocker image lsdocker volume lsdocker network lsdocker container rm -f [containerName or containerID]

(Ref: docker-handbook-borosan)

• When we create the container from the image, in every container, there is an application that is set to run by default app.
  • When this app runs, the container runs.
  • When this default app finishes/stops, the container stops.
• There could be more than one app in docker image (such as: sh, ls, basic commands)
• When the Docker container is started, it is allowed that a single application is configured to run automatically.

docker container run --name mywebserver -d -p 80:80 -v test:/usr/share/nginx/html nginxdocker container ls -adocker image pull alpinedocker image push alpinedocker image build -t hello . (run this command where “Dockerfile” is)(PS: image file name MUST be “Dockerfile”, no extension)docker save -o hello.tar test/hellodocker load -i <path to docker image tar file>docker load -i .\hello.tar

Goto:App: Creating First Docker Image and Container using Docker File

(Ref: life-cycle-medium)

e.g. [imageName]=alpine, busybox, nginx, ubuntu, etc.docker image pull [imageName]docker container run [imageName]docker container start [containerId or containerName]docker container stop [containerId or containerName]docker container pause [containerId or containerName]docker container unpause [containerId or containerName]

• Images are read only (R/O).
• When containers are created, new read-write (R/W) thin layer is created.

(Ref: docs.docker.com)

• Containers do not save the changes/logs when erased if there is not any binding to volume/mount.
• For persistence, volumes/mounts MUST be used.
• e.g. Creating a log file in the container. When the container is deleted, the log file also deleted with the container. So volumes/binding mounts MUST be used to provide persistence!

(Ref: udemy-course:adan-zye-docker)

• Volumes and binding mounts must be used for saving logs, output files, and input files.
• When volumes bind to the directory in the container, this directory and volume are synchronized.

docker volume create [volumeName]docker volume create testdocker container run --name [containerName] -v [volumeName]:[pathInContainer] [imageName]docker container run --name c1 -v test:/app alpine

Goto:App: Binding Volume to the Different Containers

docker container run --name [containerName] -v [pathInHost]:[pathInContainer] [imageName]docker container run --name c1 -v C:\test:/app alpine

(Ref: Docker.com)

Goto:App: Binding Mount to ContainerGoto:App: Transferring Content between Host PC and Docker Container

• Docker containers work like VMs.
• Every Docker container has network connections
• Docker Network Drivers:
  • None
  • Bridge
  • Host
  • Macvlan
  • Overlay

• Default Network Driver: Bridge (--net bridge)

docker network create [networkName]docker network create bridge1docker container run --name [containerName] --net [networkName] [imageName] docker container run --name c1 --net bridge1 alpine shdocker network inspect bridge1docker container run --name c2 --net bridge1 alpine shdocker network connect bridge1 c2docker network inspect bridge1docker network disconnect bridge1 c2

• Creating a new network using customized network parameters:

docker network create --driver=bridge --subnet=10.10.0.0/16 --ip-range=10.10.10.0/24 --gateway=10.10.10.10 newbridge

(Ref: Docker.com)

• Containers reach host network interfaces (--net host)

docker container run --name [containerName] --net [networkName] [imageName] docker container run --name c1 --net host alpine sh

(Ref: Docker.com)

• Each Container has its own MAC interface (--net macvlan)

(Ref: Docker.com)

• Containers that work on different PCs/hosts can work as the same network (--net overlay)

(Ref: Docker.com)

• Mapping Host PC's port to container port:

-p [hostPort]:[containerPort], --publish [hostPort]:[containerPort] e.g. -p 8080:80, -p 80:80docker container run --name mywebserver -d -p 80:80 nginx

• Docker Logs show /dev/stdout, /dev/stderror

docker logs --details [containerName]

Goto:App: Creating Docker Container using Dockerfile to Build C++ on Ubuntu18.04

Goto:App: Creating Docker Container using Dockerfile to Build C++ on Windows

FROM python:alpine3.7COPY . /appWORKDIR /appRUN pip install -r requirements.txtEXPOSE 5000CMD python ./index.py

FROM ubuntu:18.04RUN apt-get update -yRUN apt-get install default-jre -yWORKDIR /myappCOPY /myapp .CMD ["java","hello"]

• Multistage Docker File (Creating temporary container):
  • In the example, JDK (Java Development Kit) based temporary image (~440MB) container is created for compilation.
  • Compiled files are copied into JRE (Java Runtime Environment) based image (~145MB). Finally, we have only JRE based image.

COPY --from=<stage 1> stage1/src stage2/destination

• In the example below, 'compiler' is 'stage1'.

FROM mcr.microsoft.com/java/jdk:8-zulu-alpine AS compilerCOPY /myapp /usr/src/myappWORKDIR /usr/src/myappRUN javac hello.javaFROM mcr.microsoft.com/java/jre:8-zulu-alpine WORKDIR /myappCOPY --from=compiler /usr/src/myapp .CMD ["java", "hello"]

• Create Image using Dockerfile

docker image build -t hello . (run this command where “Dockerfile” is)(PS: image file name MUST be “Dockerfile”, no extension)docker image pull [imageName]docker image push [imageName]docker image tag [imageOldName] [imageNewName](PS: If you want to push DockerHub, [imageNewName]=[username]/[imageName]:[version])docker save -o hello.tar test/hellodocker load -i <path to docker image tar file>docker load -i .\hello.tar

Goto:App: Creating First Docker Image and Container using Docker File

• Define and run multi-container applications with Docker.
• Easy to create Docker components using one file: Docker-Compose file
• It is a YAML file that defines components:
  • Services,
  • Volumes,
  • Networks,
  • Secrets
• Sample "docker-compose.yml" file:

version: "3.8"services:  mydatabase:    image: mysql:5.7    restart: always    volumes:       - mydata:/var/lib/mysql    environment:       MYSQL_ROOT_PASSWORD: somewordpress      MYSQL_DATABASE: wordpress      MYSQL_USER: wordpress      MYSQL_PASSWORD: wordpress    networks:      - mynet  mywordpress:    image: wordpress:latest    depends_on:       - mydatabase    restart: always    ports:      - "80:80"      - "443:443"    environment:       WORDPRESS_DB_HOST: mydatabase:3306      WORDPRESS_DB_USER: wordpress      WORDPRESS_DB_PASSWORD: wordpress      WORDPRESS_DB_NAME: wordpress    networks:      - mynetvolumes:  mydata: {}networks:  mynet:    driver: bridge

• After saving the file as "docker-compose.yml", run the following commands where the docker-compose file is, to create containers, volumes, networks:

docker-compose up -ddocker-compose down

Goto:App: Docker-Compose File - Creating 2 Different Containers: WordPress Container depends on MySql Container

One of the Container Orchestration tool:

• Automating and scheduling the
  • deployment,
  • management,
  • scaling, and
  • networking of containers
• Container Orchestration tools:
  • Docker Swarm,
  • Kubernetes,
  • Mesos

(Ref: udemy-course:adan-zye-docker)

• With Docker Stack, multiple services can be created with one file.
• It is like a Docker-Compose file but it has more features than a Docker-compose file: update_config, replicas.
• But it is running on when Docker Swarm mode is activated.
• Network must be 'overlay'.

docker service create --name testservice --replicas=5 -p 8080:80 nginxdocker service ps testservice (listing running containers on which nodes)docker service inspect testservice

docker service scale testservice=10 (scaling up the containers to 10 replicas)

docker service update --detach --update-delay 5s --update-parallelism 2 --image nginx:v2 testservice (previous state: testservice created, now updating)docker service update --help (to see the parameters of update)

docker service rollback --detach testservice (rollbacking to previous state)

Goto:App: Creating Docker Swarm Cluster With 5 PCs using PlayWithDocker : 3 x WordPress Containers and 1 x MySql Container using Docker-Compose File

• https://labs.play-with-docker.com/

Goto:Docker Commands Cheatsheet

• Original Docker Document:https://docs.docker.com/get-started/
• Cheatsheet:https://github.com/wsargent/docker-cheat-sheet
• Workshop:https://dockerlabs.collabnix.com/workshop/docker/
• All-in-one Docker Image for Deep Learning:https://github.com/floydhub/dl-docker
• Various Dockerfiles for Different Purposes:https://github.com/jessfraz/dockerfiles
• Docker Tutorial for Beginners [FULL COURSE in 3 Hours]- Youtube:https://www.youtube.com/watch?v=3c-iBn73dDE&t=6831s
• Docker and Kubernetes Tutorial | Full Course [2021] - Youtube:https://www.youtube.com/watch?v=bhBSlnQcq2k&t=3088s

• Docker.com
• docs.docker.com
• docker-handbook-borosan
• life-cycle-medium
• Infoworld
• ItNext
• udemy-course:adan-zye-docker