Quarkus - Deploying on OpenShift
This guide covers generating and deploying OpenShift resources based on sane default and user supplied configuration.
To complete this guide, you need:
roughly 5 minutes
JDK 1.8+ installed with
Apache Maven 3.6.2+
access to an OpenShift cluster (Minishift is a viable option)
First, we need a new project that contains the OpenShift extension. This can be done using the following command:
mvn io.quarkus:quarkus-maven-plugin:1.8.1.Final:create \ -DprojectGroupId=org.acme \ -DprojectArtifactId=openshift-quickstart \ -DclassName="org.acme.rest.GreetingResource" \ -Dpath="/greeting" \ -Dextensions="openshift" cd openshift-quickstart
Quarkus offers the ability to automatically generate OpenShift resources based on sane default and user supplied configuration. The OpenShift extension is actually a wrapper extension that brings together the kubernetes and container-image-s2i extensions with sensible defaults so that it’s easier for the user to get started with Quarkus on OpenShift.
When we added the OpenShift extension to the command line invocation above, the following dependency was added to the
<dependency> <groupId>io.quarkus</groupId> <artifactId>quarkus-openshift</artifactId> </dependency>
By adding this dependency, we now have the ability to configure the OpenShift resource generation and application using the usual
application.properties approach that Quarkus provides.
The configuration items that are available can be found in:
Furthermore, the items provided by
io.quarkus.deployment.ApplicationConfig affect the OpenShift resources.
Building is handled by the container-image-s2i extension. To trigger a build:
./mvnw clean package -Dquarkus.container-image.build=true
The build that will be performed is an s2i binary build. The input of the build is the jar that has been built locally and the output of the build is an ImageStream that is configured to automatically trigger a deployment.
Out of the box the openshift extension is configured to use container-image-s2i. However, it’s still possible to use other container image extensions like:
When a non-s2i container image extension is used, an ImageStream is created that is pointing to an external
dockerImageRepository. The image is built and pushed to the registry and the ImageStream populates the tags that are available in the
To select which extension will be used for building the image:
To trigger a deployment:
./mvnw clean package -Dquarkus.kubernetes.deploy=true
The command above will trigger a container image build and will apply the generated OpenShift resources, right after.
The generated resources are using OpenShift’s
DeploymentConfig that is configured to automatically trigger a redeployment when a change in the
ImageStream is noticed.
In other words, any container image build after the initial deployment will automatically trigger redeployment, without the need to delete, update or re-apply the generated resources.
All available customization options are available in the OpenShift configuration options.
Some examples are provided in the sections below:
To expose a
Route for the Quarkus application:
Tip: You don’t necessarily need to add this property in the
application.properties. You can pass it as a command line argument:
./mvnw clean package -Dquarkus.openshift.expose=true
The same applies to all properties listed below.
To add an annotation in the generated resources:
The command above will add
MY_ENV_VAR=foobar as an environment variable.
Please note that the key
my-env-var will be converted to uppercase and dashes will be replaced by underscores resulting in
You may also noticed that in contrast to labels, and annotations for environment variables you don’t just use a key=value approach. That is because for environment variables there are additional options rather than just value.
To add all key value pairs of a
Secret as environment variables:
The OpenShift extension allows the user to configure both volumes and mounts for the application.
Any volume can be mounted with a simple configuration:
This will add a mount to my pod for volume
my-volume to path
The volumes themselves can be configured as shown in the sections below:
OpenShift also provides the ability to use Knative via the OpenShift Serverless functionality.
The first order of business is to instruct Quarkus to generate Knative resources by setting:
In order to leverage OpenShift S2I to build the container image on the cluster and use the resulting container image for the Knative application, we need to set a couple of configuration properties:
# set the Kubernetes namespace which will be used to run the application quarkus.container-image.group=geoand # set the container image registry - this is the standard URL used to refer to the internal OpenShift registry quarkus.container-image.registry=image-registry.openshift-image-registry.svc:5000
The application can then be deployed to OpenShift Serverless by enabling the standard