Docker Learning

Docker Learning Course

Duration: Two weeks, three days per each week, 1 hour per day

These sessions were broadcast on YouTube during the last days of April 2020. There is a playlist with the recordings of the sessions.

Week 1

Learning Docker

Day 1

Inception with Docker basics

• Container execution and deatached execution
• Images
  • Layers
  • Tags
  • Docker public registry
• Builds
  • Dockerfile
  • Build, commit, push
• CMD and ENTRYPOINT differences
• Pets vs Cattle
• Docker Development Flow

Reference repositories:

• Daniele Siddi's GitHub - Curso de introducción a Docker
• CMD vs ENTRYPOINT in Stackoverflow
• Brian DeHamer - Dockerfile ADD vs COPY

Recorded session: https://www.youtube.com/watch?v=I2f5CElMQo4&list=PLsp2U1HPiXXVurbxaYF_2qAqydFgp6Pq2&index=2&t=0s

Day 2

Docker Elements

• Containers
• Images
• Networks
• Volumes

Refertence repositories:

• Red Panda CI's GitHub - Jenkins Workshop
• Moncho's Github - DRY (container management CLI)

Recorded session: https://www.youtube.com/watch?v=CgbJmlMJvbI&list=PLsp2U1HPiXXVurbxaYF_2qAqydFgp6Pq2&index=2

Day 3

Docker Compose

• Docker compose file
• Parameters with .env
• Platform definition and usage
• Real examples with live projects

Reference repositories:

• Sergio Ortega Gome's GitHub - Symfony 4 App Example

External resources:

• Dockerfile linter resource - FROM:latest

Recorded session: https://www.youtube.com/watch?v=SSZAqBlkl5s&list=PLsp2U1HPiXXVurbxaYF_2qAqydFgp6Pq2&index=3

Week 2

Using Docker

Day 4

Docker compose in real projects

Reference repositories: none that we can share :)

Recorded session: https://www.youtube.com/watch?v=SV8AIqcR3XE&list=PLsp2U1HPiXXVurbxaYF_2qAqydFgp6Pq2&index=4

Day 5

Choose one of the following options

Docker in depth

• Docker in Docker
  • Ubuntu DIND
  • Official Docker in Docker
• Quality pieces with Docker
  • Jenkins in Docker
  • Sonar with real live project
  • Zalenium: Selenium Grid with steroids in Docker
• Windows in Docker

Reference repositories:

• Jerôme Petazzoni - Using Docker in Docker
• Red Panda CI's GitHub
  • Ubuntu DIND
• Ayuda Digital
  • Jenkins DIND
  • Jenkins Pipeline Library
• Informática Parmadux's GitHub - Odoo
• Docker - Docker in Docker
• Zalando IT's GitHub - Zalenium
• Aerokube's GitHub - Windows Images

Dockerize an application

Put Docker on the Spring Boot Angular4 Heroes sample application.

Stages:

1. Follow the instructions of the project and install on your workstation or laptop all the stuff to execute the application.
2. Build a docker-compose platform in two services: database and application.
3. Compare with the Kairops Fork of the project and the solution proposed here. Don't cheat and look only when you are finished the sedond stage.

Tips:

• Use MySQL 5.x or MariaDB 5.x versions for the database service.
• Use debian based image for the application service.
• Add --disable-host-check and --host 0.0.0.0 parameters for the ng start command.

Top goal:

• Try to split the application in two Docker services: backend and frontend.

Recorded session: https://www.youtube.com/watch?v=Rv_GHyt6scY&list=PLsp2U1HPiXXVurbxaYF_2qAqydFgp6Pq2&index=5

Day 6

Choose one of the following options

BDD with Docker

Use the project Duing to dessign and execute a BDD test

Demonstrate how we can use Docker to run a complete linux Desktop environment with all the tools needed to materialize complex tasks.

Reference repositories:

• Ayuda Digital's GitHub - Docker Ubuntu INstant Gherkin
• Sergio Ortega Gomez's GitHub - Docker Ubuntu 18.10 Mate Desktop

Kubernetes Inception

Take a look at Kubernetes using local minikube and this Docker Compose Example project.

Thanks to Álvaro for this work.

Recorded session: https://www.youtube.com/watch?v=-G8KQRNxvWQ&list=PLsp2U1HPiXXVurbxaYF_2qAqydFgp6Pq2&index=6

Further reading

• General Concepts about Software Development (Spanish)
• Play with Docker
• Learning Docker with Katacoda courses

Stuff Intallation

You can download the whole Docker images and clone the whole referenced repositories with a script within the project.

Execute the command:

devcontrol/actions/install-stuff.sh exec

...or use devcontrol install-stuff if you have Devcontrol installed on your system) and wait for the script to finish.

BDD examples

Find in the bdd-examples directory of the repository some examples of BDD test created as part of the day 6 session.

To execute the tests:

1. Start a duing container with the repository shared as volume within it.

   docker run --name duing \
             -p 3389:3389 \
             --shm-size 1g \
             -dit --restart unless-stopped \
             -v $(pwd):/opt/docker-learning \
             ayudadigital/duing

2. Copy the /opt/docker-learning/bdd-examples/test/ directory in /opt/duingdemo/ci-scripts/test/. This will add the examples to the features directory.

   $ docker exec -u ubuntu duing cp -rv /opt/docker-learning/bdd-examples/test/ /opt/duingdemo/ci-scripts/
   '/opt/docker-learning/bdd-examples/test/cucumber/features/step_definitions/bddfire_steps.rb' -> '/opt/duingdemo/ci-scripts/test/cucumber/features/step_definitions/bddfire_steps.rb'
   '/opt/docker-learning/bdd-examples/test/cucumber/features/github_search.feature' -> '/opt/duingdemo/ci-scripts/test/cucumber/features/github_search.feature'

3. Follow the instructions of the Duing project.

   Take care that github can't be tested with PhantomJS, so the rake poltergeist command will end with an error.

   ubuntu@7a0e1ec3060f:/opt/duingdemo/ci-scripts/test/cucumber$ rake poltergeist
   /usr/bin/ruby2.5 -S bundle exec cucumber features -p poltergeist --format pretty --profile html -t ~@api
   {"baseurl"=>"https://www.google.es", "take_screenshots"=>false, "screenshot_delay"=>1, "browser_width"=>1024}
   Using the poltergeist and html profiles...
   Feature: Google Search to explore BDDfire
   
     Scenario: View home page                      # features/bddfire.feature:4
       Given I am on "http://www.google.com?hl=en" # bddfire-3.0.2/lib/bddfire/web/web_steps.rb:2
       When I fill in "q" with the text "bddfire"  # bddfire-3.0.2/lib/bddfire/web/web_steps.rb:6
       Then I should see "Sign in"                 # bddfire-3.0.2/lib/bddfire/web/web_steps.rb:10
   
   Feature: Github search for a library
   
     Scenario: Search library within github                # features/github_search.feature:3
       Given I am on "https://www.github.com"              # bddfire-3.0.2/lib/bddfire/web/web_steps.rb:2
         Request to 'https://www.github.com' failed to reach server, check DNS and/or server status (Capybara::Poltergeist::StatusFailError)
         features/github_search.feature:4:in `Given I am on "https://www.github.com"'
       When I fill in "Search GitHub" with the text "vavr" # bddfire-3.0.2/lib/bddfire/web/web_steps.rb:6
       And I press intro key with my little finger         # features/step_definitions/bddfire_steps.rb:3
   
   Failing Scenarios:
   cucumber -p poltergeist -p html features/github_search.feature:3 # Scenario: Search library within github
   
   2 scenarios (1 failed, 1 passed)
   6 steps (1 failed, 2 skipped, 3 passed)
   0m1.410s