Kubernetes Advanced

Before going further, make sure that you have quarkus-kubernetes dependency in your pom.xml.

In the previous examples we used the autogenerated files together with YAML fragments defined in src/main/kubernetes for deploying to Kubernetes/OpenShift. As involuntary mistakes can occur in manually created YAML files, it would be great to test those before applying them in any namespace.

To make testing against a mock Kubernetes API extremely simple, Quarkus provides the WithKubernetesTestServer annotation which automatically launches a mock of the Kubernetes API server and sets the proper environment variables needed. To take advantage of these features, the quarkus-test-kubernetes-client dependency needs to be added in pom.xml:

    <dependency>
      <groupId>io.quarkus</groupId>
      <artifactId>quarkus-test-kubernetes-client</artifactId>
      <scope>test</scope>
    </dependency>

Integration tests to avoid Kubernetes YAML issues

In the folder src/main/kubernetes add pdb.yml file with the following content:

apiVersion: policy/v1
kind: PodDisruptionBudget
metadata:
spec:
  minAvailable: 1
  selector:
    matchLabels:
      app.kubernetes.io/name: quarkus-app-workshop

Typically you will install src/main/kubernetes/pdb.yml in an Kubernetes/OpenShift environment and will observe that the configuration is rejected. However, you can avoid such a scenario by creating an integration test for the PodDisruptionBudget resource defined in the file:

package org.acme;

import io.fabric8.kubernetes.api.model.policy.v1.PodDisruptionBudget;
import io.fabric8.kubernetes.client.KubernetesClientException;
import io.fabric8.kubernetes.client.server.mock.KubernetesServer;
import io.quarkus.test.junit.DisabledOnNativeImage;
import io.quarkus.test.junit.QuarkusTest;
import io.quarkus.test.kubernetes.client.KubernetesTestServer;
import io.quarkus.test.kubernetes.client.WithKubernetesTestServer;
import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertThrows;

@WithKubernetesTestServer(1)
@QuarkusTest
@DisabledOnNativeImage(2)
public class PodDisruptionBudgetTest {

    @KubernetesTestServer(3)
    KubernetesServer mocKubernetesServer;

    @Test
    public void testPdbFromFile() {
        String path = "./src/main/kubernetes/pdb.yml";(4)
        PodDisruptionBudget pdb = mocKubernetesServer.getClient().policy().v1().podDisruptionBudget().load(path).get();
        assertThrows(KubernetesClientException.class, () -> mocKubernetesServer.getClient().policy().v1().podDisruptionBudget().create(pdb));(5)
    }

}

1	Annotate the test as one working in a mocked Kubernetes context.
2	Exclude this test when running the native executable.
3	Add the mock Kubernetes server context.
4	Specify the path to the resource under test.
5	Try to create the Kubernetes resource based on the configuration inside file.

By running the test (via ContinuousTesting/IDE/application package) you can get exceptions but also what is wrong with the resource.