Introduction

For creating a LAMP server for Web development

slides.com/mikebarkas/intro-docker-for-developers

/live

Presentation Overview

Discuss basic Docker concepts including:

Images

Containers

Command line tools

Example building a LAMP stack

Docker Intro

What is Docker?

Docker is a software container platform

"A container image is a lightweight, stand-alone, executable package of a piece of software that includes everything needed to run it: code, runtime, system tools, system libraries, settings."

- docker.com

What is a container?

Virtual Machine vs Docker

Hardware

Host OS

Hypervisor (vbox or vmware)

Virtual Machine

Guest OS

Application

Packages

Libraries

Guest OS

Application

Packages

Libraries

Hardware

Host OS

Docker Engine

Application

Packages

Libraries

Docker

Application

Packages

Libraries

Images and Containers

Hardware

Host OS

Docker Engine

Application

Packages

Libraries

Docker

Created with Docker image

Docker container

One or more images can be run in a container

Only the processes/programs from the images are available in the container

Docker Images

A Docker image is built from a series of layers

Each command in the Dockerfile creates a read-only layer

The Dockerfile contains commands or file system changes used during runtime.

An image does not have state and it never changes

Dockerfile Example

FROM ubuntu:16.04

RUN apt-get update

RUN apt-get install -y openssh-server


EXPOSE 22

CMD ["/usr/sbin/sshd", "-D"]

Image used in container

Read-only layers

Docker may use these for other builds

List Docker Images

 - docker images
REPOSITORY                         TAG                 IMAGE ID            CREATED             SIZE
mikebarkas/apache24-php70          0.1                 fd5cf1167757        3 weeks ago         367 MB
apache24-php56                     latest              469164cf53f7        3 weeks ago         369 MB
mikebarkas/apache24-php56          0.1                 469164cf53f7        3 weeks ago         369 MB
ubuntu14                           latest              9652fdb58ee0        4 weeks ago         688 MB
certbot_development                latest              7b8d0133e9e1        4 weeks ago         489 MB
ubuntu                             16.04               ebcd9d4fca80        5 weeks ago         118 MB
ubuntu                             trusty              2ff3b426bbaa        5 weeks ago         188 MB
mariadb                            10.1                98f78d96be9c        6 weeks ago         395 MB
ubuntu                             latest              f7b3f317ec73        8 weeks ago         117 MB
wordpress                          latest              dfbefe759772        4 months ago        400 MB
postgres                           latest              4023a747a01a        5 months ago        265 MB
mysql                              5.7                 f3694c67abdb        5 months ago        400 MB
phptest                            7.0                 2def50f66eea        7 months ago        420 MB
mikebarkas/phpunittest             7.0                 2def50f66eea        7 months ago        420 MB
mikebarkas/ubuntu14-python3-pip3   0.1                 234a4c11fce3        7 months ago        349 MB
python                             3.5                 302ab18dbdd0        7 months ago        682 MB
drupal                             7.51-apache         9f6f9f3c360d        8 months ago        437 MB
php                                7.0-cli             95963ad7e7a6        8 months ago        363 MB
ubuntu                             14.04               1e0c3dd64ccd        8 months ago        188 MB

Running Docker Containers

Run a Docker image in a container

docker run [OPTIONS] IMAGE [COMMAND] [ARG...]

Run multiple services for an application

docker-compose [COMMAND] [OPTIONS]

Docker Compose

Create multiple services in a container with a compose file

docker-compose.yml

Pull in multiple images to create services

Services will be networked with each other

Specify directories for application code

Define custom settings for the services

Docker Compose Example

version: '3'

services:
   db:
     image: mariadb:10.1
     volumes:
       - db_data:/var/lib/mysql
     environment:
       MYSQL_ROOT_PASSWORD: secretpassword
       MYSQL_DATABASE: db_name
       MYSQL_USER: db_user
       MYSQL_PASSWORD: db_password

   app:
     depends_on:
       - db
     image: mikebarkas/apache24-php70
     ports:
       - "8000:80"
     environment:
       DRUPAL_DB_HOST: db:3306
       DRUPAL_DB_USER: username
       DRUPAL_DB_PASSWORD: password

docker-compose.yml

Docker Compose Commands

docker-compose [-f <arg>...] [options] [COMMAND] [ARGS...]


Commands:

  up                 Create and start containers
  down               Stop and remove containers, networks, images, and volumes

  start              Start services
  stop               Stop services

  ps                 List containers
  rm                 Remove stopped containers
    
  (many others)

Process Overview

Create custom Docker image with a Dockerfile

Build your custom image with docker build .

Run your new image with docker run [options]

Run multi-container services as a collection for a complete application with docker-compose up

Group multiple images and specific settings with docker-compose.yml

Another Source for Images

In addition to building your custom images

https://hub.docker.com/

Docker Hub

Community repository for Docker images

- docker search node
NAME                      DESCRIPTION                                     STARS     OFFICIAL
node                      Node.js is a JavaScript-based platform for...   4083      [OK]
nodered/node-red-docker   Node-RED Docker images.                         61               
strongloop/node           StrongLoop, Node.js, and tools.                 38              
kkarczmarczyk/node-yarn   Node docker image with yarn package manage...   28           
bitnami/node              Bitnami Node.js Docker Image                    20            
siomiz/node-opencv        _/node + node-opencv                            10             
dahlb/alpine-node         small node for gitlab ci runner                 8
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