Fast Docker Save

This repo covers containerization and Docker Environment: Docker File, Image, Container, Commands, Volumes, Networks, Swarm, Stack, Service, possible scenarios.

Project README

Fast-Docker

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.

Quick Look (HowTo: LABs)

Table of Contents

Motivation

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

Needs

  • 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.

Benefits

  • 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)

Problems Docker does not solve

  • 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)

What is Docker?

  • 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)

image (Ref: Docker.com)

Architecture

image (Ref: docs.docker.com)

Installation

Docker Engine (Deamon, REST API, CLI)

  • 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.

image (Ref: Docker.com)

Docker Registry and Docker Hub

image

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

Docker Command Structure

  • docker [ManagementCommand] [Command]
docker container ls -a
docker image ls
docker volume ls
docker network ls
docker container rm -f [containerName or containerID]

image

image

Docker Container

image (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 nginx
docker container ls -a
docker image pull alpine
docker image push alpine
docker 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/hello
docker load -i <path to docker image tar file>
docker load -i .\hello.tar

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

Docker Container: Life Cycle

image (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]

Docker Container: Union File System

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

image (Ref: docs.docker.com)

Docker Volumes: Why Volumes needed?

  • 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!

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

Docker Volumes/Bind Mounts

  • 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 test
docker 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

Bind Mount

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

image (Ref: Docker.com)

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

Docker Network

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

Docker Network: Bridge

  • Default Network Driver: Bridge (--net bridge)
docker network create [networkName]
docker network create bridge1
docker container run --name [containerName] --net [networkName] [imageName] 
docker container run --name c1 --net bridge1 alpine sh
docker network inspect bridge1
docker container run --name c2 --net bridge1 alpine sh
docker network connect bridge1 c2
docker network inspect bridge1
docker 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

image (Ref: Docker.com)

Docker Network: Host

  • Containers reach host network interfaces (--net host)
docker container run --name [containerName] --net [networkName] [imageName] 
docker container run --name c1 --net host alpine sh

image (Ref: Docker.com)

Docker Network: MacVlan

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

image (Ref: Docker.com)

Docker Network: Overlay

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

image (Ref: Docker.com)

Port Mapping/Publish:

  • Mapping Host PC's port to container port:
-p [hostPort]:[containerPort], --publish [hostPort]:[containerPort] e.g. -p 8080:80, -p 80:80
docker container run --name mywebserver -d -p 80:80 nginx

Docker Log

  • Docker Logs show /dev/stdout, /dev/stderror
docker logs --details [containerName]

image

Docker Stats/Memory-CPU Limitations

image

image

image

Docker Environment Variables

image

Docker File

image

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

Sample Docker Files

FROM python:alpine3.7
COPY . /app
WORKDIR /app
RUN pip install -r requirements.txt
EXPOSE 5000
CMD python ./index.py

FROM ubuntu:18.04
RUN apt-get update -y
RUN apt-get install default-jre -y
WORKDIR /myapp
COPY /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 compiler
COPY /myapp /usr/src/myapp
WORKDIR /usr/src/myapp
RUN javac hello.java

FROM mcr.microsoft.com/java/jre:8-zulu-alpine 
WORKDIR /myapp
COPY --from=compiler /usr/src/myapp .
CMD ["java", "hello"]

Docker Image

  • 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/hello
docker load -i <path to docker image tar file>
docker load -i .\hello.tar

image

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

Docker Compose

  • 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:
      - mynet
volumes:
  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 -d
docker-compose down

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

Docker Swarm

One of the Container Orchestration tool:

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

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

Docker Stack / Docker Service

  • 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'.

Creating, Listing, Inspecting

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

Scaling

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

Updating

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)

Rollbacking

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

image

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

Play With Docker

image

Docker Commands Cheatsheet

Goto: Docker Commands Cheatsheet

References

Open Source Agenda is not affiliated with "Fast Docker" Project. README Source: omerbsezer/Fast-Docker
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Repository
omerbsezer/Fast-Docker
License
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Tags
Docker Docker Compose Docker Compose Template Docker Container Docker Image Docker Images Docker Network Docker Registry Docker Service Docker Stack Docker Swarm Docker Tutorial Docker Volumes Dockerfile Dockerhub How To Play With Docker Swarm Mode Swarm Mode Cluster

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