OpenShift Build and Deploy a JEE Application with S2I

Internal

• Build Operations
• Application Operations

Overview

This article describes the process of setting up a project that builds from sources and deploys a simple JEE application. The source of the application is exposed in GitHub. We will use https://github.com/NovaOrdis/novaordis-session-servlet (Session Servlet Example). The final artifact will be deployed in a EAP 7 instance.

Create the OpenShift Project

The application will be hosted in its own OpenShift project:

oc new-project s2i-build-example \
  --display-name='S2I Build Example' \
  --description='A JEE Application that builds from source and deploys onto a EAP 7 instance'

Identify the Application Template

Since we intend to deploy our JEE application in top of a JEE container, the simplest method is to identify the application template that matches our requirements and use it. OpenShift comes with a series of application templates, which are pre-loaded in the "openshift" project:

oc get templates -n openshift

The application template that matches our requirements is "eap70-basic-s2i"

It can be explored with:

oc get -o yaml template eap70-basic-s2i -n open shift

The template can be used "as-is", or it can be downloaded locally and modified - for example, we can change the labels applied by the template to the objects it creates, so instead of "app=eap70-basic-s2i", we can use a more custom name for our application. Some of the parameters, including the application name, are allowed to be changed on command line. It is a good idea to review the application template and identify all parameters that can be customized.

Create the Application

oc new-app eap70-basic-s2i \
  --param APPLICATION_NAME=<application-name> \
  --param HOSTNAME_HTTP=<custom-hostname-instead-of-application_name.project.default_routing_subdomain> \
  --param SOURCE_REPOSITORY_URL=<git-repository-url> \
  --param SOURCE_REPOSITORY_REF=<git-branch-tag-reference> \
  --param CONTEXT_DIR=<path-withing-git-project-to-build> \
  --param GITHUB_WEBHOOK_SECRET=<github-webhook-secret> \
  --param IMAGE_STREAM_NAMESPACE=<imagestream-namespace> \
  --param MAVEN_MIRROR_URL=<maven-mirror-to-use-for-S2I-builds> 

For more details, see:

• Hostname HTTP
• Webhook Secret
• Image Stream Namespace

Process

"Join" Projects

If the source repository pod runs in a collocated OpenShift project, and we want to use the internal DNS name, we need to join the projects.

oadm pod-network join-projects --to=cicd lab

oc new-app <openshift-project-template-name> \
 --param APPLICATION_NAME=<application-name> \
 --param SOURCE_REPOSITORY_URL=<git-url> \ 
 --param SOURCE_REPOSITORY_REF=master \
 --param CONTEXT_DIR=/

oc new-app eap64-basic-s2i \
 --param APPLICATION_NAME=tasks \
 --param SOURCE_REPOSITORY_URL=http://gogs.cicd.svc.cluster.local:3000/gogs/openshift-tasks-private \ 
 --param SOURCE_REPOSITORY_REF=master \
 --param CONTEXT_DIR=/

This command uses openshift project's "eap64-basic-s2i" template and creates:

• a build configuration
• an image stream
• a deployment configuration
• a route
• a service

--> Deploying template "openshift/eap64-basic-s2i" to project lab

     Red Hat JBoss EAP 6.4 (no https)
     ---------
     Application template for EAP 6 applications built using S2I.

     A new EAP 6 based application has been created in your project.

     * With parameters:
        * Application Name=tasks
        * Custom http Route Hostname=
        * Git Repository URL=https://gogs.cicd.svc.cluster.local:3000/gogs/openshift-tasks-private
        * Git Reference=master
        * Context Directory=/
        * Queues=
        * Topics=
        * HornetQ Password=VvEf5H0S # generated
        * Github Webhook Secret=8Xk5LAnr # generated
        * Generic Webhook Secret=mn5K7NNA # generated
        * ImageStream Namespace=openshift
        * JGroups Cluster Password=r1Elwibf # generated
        * Deploy Exploded Archives=false
        * Maven mirror URL=
        * ARTIFACT_DIR=

--> Creating resources ...
    service "tasks" created
    route "tasks" created
    imagestream "tasks" created
    buildconfig "tasks" created
    deploymentconfig "tasks" created
--> Success
    Build scheduled, use 'oc logs -f bc/tasks' to track its progress.
    Run 'oc status' to view your app.

Because the Git repository is private and protected by username/password, the initial build attempt will fail:

oc logs -f build/tasks-1
...
error: build error: failed to fetch requested repository "http://gogs.cicd.svc.cluster.local:3000/gogs/openshift-tasks-private" with provided credentials

Add Source Repository Secrets

If the source repository is protected, we need to place credentials into the builder configuration, and the builder service account environment:

oc secrets new-basicauth gogs-basicauth --username=gogs --password=...
oc secrets link builder gogs-basicauth
oc set build-secret --source bc/tasks gogs-basicauth

Restart the Build

oc start-build tasks