OpenShift Template are a starting point for creating all encompassing build and deployment of OpenShift applications.
A simple way to get started with an all encompassing build and deployment for local development is using OpenShift Templates. Other ways of building and deploying applications include using CI/CD pipeline technology e.g. Argo, Jenkins, Ansible etc.
The template will build from the Github repository, therefore we need to commit all the files to a repo.
Remember we had these two file replacements:
cp ./src/server-v2.js ./server.js
cp ./src/Dockerfile.openshift ./Dockerfile
As long as anything hasn't changed here then you have the correct server.js and Dockerfile.
Push your local repo to remote:
git add .
git commit -m "ready for template build"
git push
An OpenShift Template is a set of directives to build various OpenShift and Kubernetes resources.
The example template file is openshift/hello-world-template.yaml.
First, setup project as the developer.
oc login -u developer -p ...
oc new-project hello-t
Next add security context to the project. As kubeadmin create the SCC for the developer user named scc-developer.
oc login -u kubeadmin -p ...
# ensure kubeadmin is in the correct project
oc project hello-t
# If you create the SCC in the previous step you will get a message it already exists
# create a SecurityContextConstraint
oc create -f openshift/developer-scc.yaml
# create a service account in the Project Namespace that the developer owns
oc create sa developer-sa
# create a role to use the SCC and bind that role to the service account
# apply RBAC
oc create -f openshift/developer-rbac.yaml
oc logout
Next, as developer user trigger the build and deployment using the template which requires the parameter PROJECT (namespace) to be specified:
oc login -u developer -p ...
oc new-app -f openshift/hello-world-template.yaml -p PROJECT=hello-t
Creating a new application from template shows these messages:
--> Deploying template "hello-t/hello-world-template" for "openshift/hello-world-template.yaml" to project hello-t
Node.js
---------
Simple Hello World app in NodeJS
* With parameters:
* Name=hello-world
* Project=hello-t
* Service Account Name=developer-sa
* Memory Limit=256Mi
* Git Repository URL=https://github.com/jeremycaine/hello-world
* Git Reference=main
* Application Hostname=
* GitHub Webhook Secret=S1HLODYUX0b86WTtIllGJIN8B1cT34kDO2wpBroG # generated
* Generic Webhook Secret=MjsK1QyfAwqEiJrnNLI1dJ7VhpfHRwnKrh5iXlby # generated
* Server Listen Port=3000
--> Creating resources ...
service "hello-world-service" created
route.route.openshift.io "hello-world-route" created
imagestream.image.openshift.io "hello-world" created
imagestream.image.openshift.io "nodejs-16-minimal" created
buildconfig.build.openshift.io "hello-world-build" created
deploymentconfig.apps.openshift.io "hello-world-deployment" created
--> Success
Access your application via route 'hello-world-route-hello-t.apps-crc.testing'
Build scheduled, use 'oc logs -f buildconfig/hello-world-build' to track its progress.
Run 'oc status' to view your app.
After a few minutes the application is up and running, oc status gives
In project hello-t on server https://api.crc.testing:6443
http://hello-world-route-hello-t.apps-crc.testing (svc/hello-world-service)
dc/hello-world-deployment deploys istag/hello-world:latest <-
bc/hello-world-build docker builds https://github.com/jeremycaine/hello-world#main on istag/nodejs-16-minimal:latest
deployment #1 deployed 3 minutes ago - 1 pod
View details with 'oc describe <resource>/<name>' or list resources with 'oc get all'.
Then you can access the application with curl http://hello-world-route-hello-t.apps-crc.testing
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