OpenShift learning project

TODO list

The pod fails for CrashLoopBackOff after being deployed. The Spring App does nothing to keep the container alive. Read this if you plan to build a real app: https://serverfault.com/questions/924243/back-off-restarting-failed-container-error-syncing-pod-in-minikube
livenessProbe and readinessProbe are commented out in the template. after adding Spring Actuator the deploy crashes for OOMKilled
trigger another build at the postCommit
improve README

This project contains an OpenShift template configuration to import in a new project the build configuration for a simple java app and for a Jenkins pipeline.

OpenShift Online is free and ideal for training/trial.

Please refer to this page for a guide:

https://docs.okd.io/latest/dev_guide/index.html

OpenShift CLI is needed to follow these instructions. Please download and install it following these steps:

https://docs.openshift.com/container-platform/3.6/cli_reference/get_started_cli.html

After creating your account and logging in, type these commands (you can also run them in a single batch)

oc delete project example-pipeline-project ; sleep 20;

oc new-project example-pipeline-project ;

oc new-app jenkins-persistent; 

oc new-app -f template.yaml --build-env='MAVEN_ARGS=-e -Popenshift -Dcom.redhat.xpaas.repo.redhatga package';

oc start-build example-java-app;

These commands will:

Create a new project in Open Shift
Create an app using the jenkins-persistent image from the Openshift registry
Import the template defined in this repository which creates:
- A build configuration for a maven java app
- A build configuration for a pipeline to build and deploy the java app
Start the java app build

To start the app locally simply run mvnw spring-boot:run

Additional notes:

MAVEN_ARGS is overwritten because the S2I tool provided by OpenShift does skip the tests when building the app
To import Gradle projects you can use the jenkins-gradle-slave provided by the RedHat community (https://github.com/redhat-cop/containers-quickstarts). Unfortunately OpenShift Online is limited and does not allow you to use Docker strategy (https://stackoverflow.com/questions/46839811/allow-docker-strategy-in-openshift-3). Error from server: admission webhook "validate.build.create" denied the request: Builds with docker strategy are prohibited on this cluster
Take advantage of the OpenShift web platform when customising your first configuration. Then export the yaml template using this command (refinements will be needed):

oc get --export all -o yaml > <path>/example-pipeline-app-in-oc/oc/template.yaml
When creating the app from the template file, oc will print all the parameter values on the stdout. You can find there the GITHUB_WEBHOOK_SECRET value you need to use as secret in the URL in GitHub. You neeed to do this configuration manually. This way every push the build will automatically started with the new code.
The GITHUB_WEBHOOK_SECRET value is the one to make the webhook URL difficult to find. Do not mismatch it with the additional text field you can populate in GitHub to write the X-Hub-Signature header. It could be used to make the mechanism more secure, but OpenShift still does not support it. Read this thread for further info: openshift/origin#14674

Other useful commands

Import the object singularly from a file instead of an entire app template as above

oc create -f oc/build-config.yaml ;

Get the build configurations

oc get bc ;

Get more description on a specific BuildConfig (ie. github webhook)

oc describe bc/example-java-app

Go to the Jenkins configuration

<jenkins-external-url>/configure

francesco-losciale/example-pipeline-app-in-oc

OpenShift learning project

Other useful commands