This repository contains files and instructions for students to run a few examples with OpenShift and Quay demonstrating some of the DevOps principles - automation and self-healing/no support architectures

There are total of 3 examples to do.

• Dockerfile - instructions for Docker/Podman to build a container image from this repository
• openshift-template.yaml - Template to deploy this application in OpenShift
• cgi-bin/form.py - gets value GET parameter and stores it in /dev/shm/countdown
• backend.py - periodically looks for /dev/shm/countdown and generates /dev/shm/output based on this file
• cgi-bin/display.py - shows current content of /dev/shm/output

Files above have number of ugly bugs. Most of them are intentional :-)

You will not need everything initially but this is a list of dependencies for going through these examples:

• Have OpenShift Clients (oc) binary. Can be downloaded from release page
• Get Github.com account
• Get OpenShift.io account
• Get Quay.io account

Beware - the code can trigger out of memory situations.

• Running server part: python3 -m http.server --cgi 9000
• Running backend: python3 backend.py
• Client: browser/curl

You can clean up after testing by removing following files:

• /dev/shm/countdown
• /dev/shm/output

This example should show you how you can have automatically built production code on every commit in your repository without manual intervention. This saves time and prevents manual errors.

• Fork this repository into your own space on Github
• Create new repository on Quay (plus sign at top-right)
  • Pick a name (mendelu-workshop?)
  • Make sure to make repository "Public"
  • Use "Link to a GitHub Repository Push"
  • Pick your fork of this repository
  • Pick "Trigger for all branches and tags"
  • Select Dockerfile path (/Dockerfile)
  • Select Context (/)
• Test the setup by pushing a new change to your fork

Bonus: Use podman run -it <url> /bin/bash to verify

This part will show you that deploying a fresh application can be quick and consistent. Once deployed in OpenShift the example application is more resilient to bugs.

• Go to openshift.io and sign up.
  • Note - the process will ask for your phone number to prevent duplicate sign-ups
• Create a new "Space" from your code on Github
• After creation go to "Analyze" tab
• At the bottom part of the page "Pipelines" should have build. Go to "Build #1"
• At the top right - click your name and "Copy login command"
• Run this command in your VM
  • This will require that you set up "oc" as described above
• Run oc process -f openshift-template.yaml | oc apply -f -

After a while if you go to "Overview" back in your browser, you should get a URL to your container application. You can play with cgi-bin/form.py/?value=<XX> and cgi-bin/display.py URLs.

Deploy the change you have made in Part 1.

Bonus: Fix the demonstrated bug