Ceruto/kubernetes-client

Java client for Kubernetes & OpenShift

Kubernetes & OpenShift Java Client

This client provides access to the full Kubernetes & OpenShift REST APIs via a fluent DSL.

• kubernetes-client:
• kubernetes-model-core:
• openshift-client:
• knative-client:
• tekton-client:
• servicecatalog-client:

• Usage
  • Creating a client
  • Configuring the client
  • Loading resources from external sources
  • Passing a reference of a resource to the client
  • Adapting a client
    • Adapting and close
• Mocking Kubernetes
• Who Uses Fabric8 Kubernetes Client?
• Kubernetes and Red Hat OpenShift Compatibility Matrix
• Kubernetes Client CHEAT SHEET

Usage

Creating a client

The easiest way to create a client is:

KubernetesClient client = new DefaultKubernetesClient();

DefaultOpenShiftClient implements both the KubernetesClient & OpenShiftClient interface so if you need the OpenShift extensions, such as Builds, etc then simply do:

OpenShiftClient osClient = new DefaultOpenShiftClient();

Configuring the client

This will use settings from different sources in the following order of priority:

• System properties
• Environment variables
• Kube config file
• Service account token & mounted CA certificate

System properties are preferred over environment variables. The following system properties & environment variables can be used for configuration:

Property / Environment Variable	Description	Default value
kubernetes.disable.autoConfig / KUBERNETES_DISABLE_AUTOCONFIG	Disable automatic configuration	false
kubernetes.master / KUBERNETES_MASTER	Kubernetes master URL	https://kubernetes.default.svc
kubernetes.api.version / KUBERNETES_API_VERSION	API version	v1
openshift.url / OPENSHIFT_URL	OpenShift master URL	Kubernetes master URL value
kubernetes.oapi.version / KUBERNETES_OAPI_VERSION	OpenShift API version	v1
kubernetes.trust.certificates / KUBERNETES_TRUST_CERTIFICATES	Trust all certificates	false
kubernetes.disable.hostname.verification / KUBERNETES_DISABLE_HOSTNAME_VERIFICATION		false
kubernetes.certs.ca.file / KUBERNETES_CERTS_CA_FILE
kubernetes.certs.ca.data / KUBERNETES_CERTS_CA_DATA
kubernetes.certs.client.file / KUBERNETES_CERTS_CLIENT_FILE
kubernetes.certs.client.data / KUBERNETES_CERTS_CLIENT_DATA
kubernetes.certs.client.key.file / KUBERNETES_CERTS_CLIENT_KEY_FILE
kubernetes.certs.client.key.data / KUBERNETES_CERTS_CLIENT_KEY_DATA
kubernetes.certs.client.key.algo / KUBERNETES_CERTS_CLIENT_KEY_ALGO	Client key encryption algorithm	RSA
kubernetes.certs.client.key.passphrase / KUBERNETES_CERTS_CLIENT_KEY_PASSPHRASE
kubernetes.auth.basic.username / KUBERNETES_AUTH_BASIC_USERNAME
kubernetes.auth.basic.password / KUBERNETES_AUTH_BASIC_PASSWORD
kubernetes.auth.tryKubeConfig / KUBERNETES_AUTH_TRYKUBECONFIG	Configure client using Kubernetes config	true
kubeconfig / KUBECONFIG	Name of the kubernetes config file to read	~/.kube/config
kubernetes.auth.tryServiceAccount / KUBERNETES_AUTH_TRYSERVICEACCOUNT	Configure client from Service account	true
kubernetes.tryNamespacePath / KUBERNETES_TRYNAMESPACEPATH	Configure client namespace from Kubernetes service account namespace path	true
kubernetes.auth.token / KUBERNETES_AUTH_TOKEN
kubernetes.watch.reconnectInterval / KUBERNETES_WATCH_RECONNECTINTERVAL	Watch reconnect interval in ms	1000
kubernetes.watch.reconnectLimit / KUBERNETES_WATCH_RECONNECTLIMIT	Number of reconnect attempts (-1 for infinite)	-1
kubernetes.connection.timeout / KUBERNETES_CONNECTION_TIMEOUT	Connection timeout in ms (0 for no timeout)	10000
kubernetes.request.timeout / KUBERNETES_REQUEST_TIMEOUT	Read timeout in ms	10000
kubernetes.rolling.timeout / KUBERNETES_ROLLING_TIMEOUT	Rolling timeout in ms	900000
kubernetes.logging.interval / KUBERNETES_LOGGING_INTERVAL	Logging interval in ms	20000
kubernetes.scale.timeout / KUBERNETES_SCALE_TIMEOUT	Scale timeout in ms	600000
kubernetes.websocket.timeout / KUBERNETES_WEBSOCKET_TIMEOUT	Websocket timeout in ms	5000
kubernetes.websocket.ping.interval / kubernetes_websocket_ping_interval	Websocket ping interval in ms	30000
kubernetes.max.concurrent.requests.per.host / KUBERNETES_MAX_CONCURRENT_REQUESTS_PER_HOST		5
kubernetes.impersonate.username / KUBERNETES_IMPERSONATE_USERNAME	Impersonate-User HTTP header value
kubernetes.impersonate.group / KUBERNETES_IMPERSONATE_GROUP	Impersonate-Group HTTP header value
kubernetes.tls.versions / KUBERNETES_TLS_VERSIONS	TLS versions separated by ,	TLSv1.2
kubernetes.truststore.file / KUBERNETES_TRUSTSTORE_FILE
kubernetes.truststore.passphrase / KUBERNETES_TRUSTSTORE_PASSPHRASE
kubernetes.keystore.file / KUBERNETES_KEYSTORE_FILE
kubernetes.keystore.passphrase / KUBERNETES_KEYSTORE_PASSPHRASE

Alternatively you can use the ConfigBuilder to create a config object for the Kubernetes client:

Config config = new ConfigBuilder().withMasterUrl("https://mymaster.com").build();
KubernetesClient client = new DefaultKubernetesClient(config);

Using the DSL is the same for all resources.

List resources:

NamespaceList myNs = client.namespaces().list();

ServiceList myServices = client.services().list();

ServiceList myNsServices = client.services().inNamespace("default").list();

Get a resource:

Namespace myns = client.namespaces().withName("myns").get();

Service myservice = client.services().inNamespace("default").withName("myservice").get();

Delete:

Namespace myns = client.namespaces().withName("myns").delete();

Service myservice = client.services().inNamespace("default").withName("myservice").delete();

Editing resources uses the inline builders from the Kubernetes Model:

Namespace myns = client.namespaces().withName("myns").edit()
                   .editMetadata()
                     .addToLabels("a", "label")
                   .endMetadata()
                   .done();

Service myservice = client.services().inNamespace("default").withName("myservice").edit()
                     .editMetadata()
                       .addToLabels("another", "label")
                     .endMetadata()
                     .done();

In the same spirit you can inline builders to create:

Namespace myns = client.namespaces().createNew()
                   .withNewMetadata()
                     .withName("myns")
                     .addToLabels("a", "label")
                   .endMetadata()
                   .done();

Service myservice = client.services().inNamespace("default").createNew()
                     .withNewMetadata()
                       .withName("myservice")
                       .addToLabels("another", "label")
                     .endMetadata()
                     .done();

You can also set the apiVersion of the resource like in the case of SecurityContextConstraints :

SecurityContextConstraints scc = new SecurityContextConstraintsBuilder()
		.withApiVersion("v1")
		.withNewMetadata().withName("scc").endMetadata()
		.withAllowPrivilegedContainer(true)
		.withNewRunAsUser()
		.withType("RunAsAny")
		.endRunAsUser()
		.build();

Following events

Use io.fabric8.kubernetes.api.model.Event as T for Watcher:

client.events().inAnyNamespace().watch(new Watcher<Event>() {

  @Override
  public void eventReceived(Action action, Event resource) {
    System.out.println("event " + action.name() + " " + resource.toString());
  }

  @Override
  public void onClose(KubernetesClientException cause) {
    System.out.println("Watcher close due to " + cause);
  }

});

Working with extensions

The kubernetes API defines a bunch of extensions like daemonSets, jobs, ingresses and so forth which are all usable in the extensions() DSL:

e.g. to list the jobs...

jobs = client.batch().jobs().list();

Loading resources from external sources

There are cases where you want to read a resource from an external source, rather than defining it using the clients DSL. For those cases the client allows you to load the resource from:

• A file (Supports both java.io.File and java.lang.String)
• A url
• An input stream

Once the resource is loaded, you can treat it as you would, had you created it yourself.

For example lets read a pod, from a yml file and work with it:

Pod refreshed = client.load('/path/to/a/pod.yml').fromServer().get();
Boolean deleted = client.load('/workspace/pod.yml').delete();
LogWatch handle = client.load('/workspace/pod.yml').watchLog(System.out);

Passing a reference of a resource to the client

In the same spirit you can use an object created externally (either a reference or using its string representation).

For example:

Pod pod = someThirdPartyCodeThatCreatesAPod();
Boolean deleted = client.resource(pod).delete();

Adapting the client

The client supports plug-able adapters. An example adapter is the OpenShift Adapter which allows adapting an existing KubernetesClient instance to an OpenShiftClient one.

For example:

KubernetesClient client = new DefaultKubernetesClient();

OpenShiftClient oClient = client.adapt(OpenShiftClient.class);

The client also support the isAdaptable() method which checks if the adaptation is possible and returns true if it does.

KubernetesClient client = new DefaultKubernetesClient();
if (client.isAdaptable(OpenShiftClient.class)) {
    OpenShiftClient oClient = client.adapt(OpenShiftClient.class);
} else {
    throw new Exception("Adapting to OpenShiftClient not support. Check if adapter is present, and that env provides /oapi root path.");
}

Adapting and close

Note that when using adapt() both the adaptee and the target will share the same resources (underlying http client, thread pools etc). This means that close() is not required to be used on every single instance created via adapt. Calling close() on any of the adapt() managed instances or the original instance, will properly clean up all the resources and thus none of the instances will be usable any longer.

Mocking Kubernetes

Along with the client this project also provides a kubernetes mock server that you can use for testing purposes. The mock server is based on https://github.com/square/okhttp/tree/master/mockwebserver but is empowered by the DSL and features provided by https://github.com/fabric8io/mockwebserver.

The Mock Web Server has two modes of operation:

• Expectations mode
• CRUD mode

Expectations mode

It's the typical mode where you first set which are the expected http requests and which should be the responses for each request. More details on usage can be found at: https://github.com/fabric8io/mockwebserver

This mode has been extensively used for testing the client itself. Make sure you check kubernetes-test.

To add a Kubernetes server to your test:

 @Rule
 public KubernetesServer server = new KubernetesServer();

CRUD mode

Defining every single request and response can become tiresome. Given that in most cases the mock webserver is used to perform simple crud based operations, a crud mode has been added. When using the crud mode, the mock web server will store, read, update and delete kubernetes resources using an in memory map and will appear as a real api server.

To add a Kubernetes Server in crud mode to your test:

 @Rule
 public KubernetesServer server = new KubernetesServer(true, true);

Then you can use the server like:

@Test
public void testInCrudMode() {
KubernetesClient client = server.getClient();
final CountDownLatch deleteLatch = new CountDownLatch(1);
final CountDownLatch closeLatch = new CountDownLatch(1);

  //CREATE
  client.pods().inNamespace("ns1").create(new PodBuilder().withNewMetadata().withName("pod1").endMetadata().build());

  //READ
  podList = client.pods().inNamespace("ns1").list();
  assertNotNull(podList);
  assertEquals(1, podList.getItems().size());

  //WATCH
  Watch watch = client.pods().inNamespace("ns1").withName("pod1").watch(new Watcher<Pod>() {
      @Override
      public void eventReceived(Action action, Pod resource) {
        switch (action) {
          case DELETED:
            deleteLatch.countDown();
            break;
          default:
            throw new AssertionFailedError(action.toString().concat(" isn't recognised."));
        }
      }
  
      @Override
      public void onClose(KubernetesClientException cause) {
        closeLatch.countDown();
      }
  });

  //DELETE
  client.pods().inNamespace("ns1").withName("pod1").delete();

  //READ AGAIN
  podList = client.pods().inNamespace("ns1").list();
  assertNotNull(podList);
  assertEquals(0, podList.getItems().size());

  assertTrue(deleteLatch.await(1, TimeUnit.MINUTES));
  watch.close();
  assertTrue(closeLatch.await(1, TimeUnit.MINUTES));
}

JUnit5 support through extension

You can use KubernetesClient mocking mechanism with JUnit5. Since it doesn't support @Rule and @ClassRule there is dedicated annotation @EnableKubernetesMockClient. If you would like to create instance of mocked KubernetesClient for each test (JUnit4 @Rule) you need to declare instance of KubernetesClient as shown below.

@EnableKubernetesMockClient
class ExampleTest {

    KubernetesClient client;

    @Test
    public void testInStandardMode() {
        ...
    }
}

In case you would like to define static instance of mocked server per all the test (JUnit4 @ClassRule) you need to declare instance of KubernetesClient as shown below. You can also enable crudMode by using annotation field crud.

@EnableKubernetesMockClient(crud = true)
class ExampleTest {

    static KubernetesClient client;

    @Test
    public void testInCrudMode() {
        ...
    }
}

Compatibility Matrix

	Kubernetes 1.4.9	Kubernetes 1.6.0	Kubernetes 1.7.0	Kubernetes 1.9.0	Kubernetes 1.10.0	Kubernetes 1.11.0	Kubernetes 1.12.0	Kubernetes 1.14.2	Kubernetes 1.15.3	Kubernetes 1.17.0	Kubernetes 1.18.0
kubernetes-client 1.3.92	+	+	-	-	-	-	-	-	-	-	-
kubernetes-client 3.0.3	-	-	✓	-	-	-	-	-	-	-	-
kubernetes-client 3.0.10	-	✓	✓	✓	-	-	-	-	-	-	-
kubernetes-client 3.0.11	-	✓	✓	✓	-	-	-	-	-	-	-
kubernetes-client 3.1.12	-	✓	✓	✓	-	-	-	-	-	-	-
kubernetes-client 3.2.0	-	✓	✓	✓	-	-	-	-	-	-	-
kubernetes-client 4.0.0	-	✓	✓	✓	-	-	-	-	-	-	-
kubernetes-client 4.1.0	-	✓	✓	✓	-	-	-	-	-	-	-
kubernetes-client 4.1.1	-	-	-	✓	✓	✓	✓	-	-	-	-
kubernetes-client 4.1.2	-	-	-	✓	✓	✓	✓	-	-	-	-
kubernetes-client 4.1.3	-	-	-	✓	✓	✓	✓	-	-	-	-
kubernetes-client 4.2.0	-	-	-	✓	✓	✓	✓	-	-	-	-
kubernetes-client 4.2.1	-	-	-	✓	✓	✓	✓	-	-	-	-
kubernetes-client 4.2.2	-	-	-	✓	✓	✓	✓	-	-	-	-
kubernetes-client 4.3.0	-	-	-	✓	✓	✓	✓	✓	-	-	-
kubernetes-client 4.3.1	-	-	-	✓	✓	✓	✓	✓	-	-	-
kubernetes-client 4.4.0	-	-	-	✓	✓	✓	✓	✓	-	-	-
kubernetes-client 4.4.1	-	-	-	✓	✓	✓	✓	✓	-	-	-
kubernetes-client 4.4.2	-	-	-	✓	✓	✓	✓	✓	-	-	-
kubernetes-client 4.5.0	-	-	-	✓	✓	✓	✓	✓	-	-	-
kubernetes-client 4.5.1	-	-	-	✓	✓	✓	✓	✓	-	-	-
kubernetes-client 4.5.2	-	-	-	✓	✓	✓	✓	✓	-	-	-
kubernetes-client 4.6.0	-	-	-	✓	✓	✓	✓	✓	✓	-	-
kubernetes-client 4.6.1	-	-	-	✓	✓	✓	✓	✓	✓	-	-
kubernetes-client 4.6.2	-	-	-	✓	✓	✓	✓	✓	✓	-	-
kubernetes-client 4.6.3	-	-	-	✓	✓	✓	✓	✓	✓	-	-
kubernetes-client 4.6.4	-	-	-	✓	✓	✓	✓	✓	✓	-	-
kubernetes-client 4.7.0	-	-	-	✓	✓	✓	✓	✓	✓	✓	-
kubernetes-client 4.7.1	-	-	-	✓	✓	✓	✓	✓	✓	✓	-
kubernetes-client 4.8.0	-	-	-	✓	✓	✓	✓	✓	✓	✓	-
kubernetes-client 4.9.0	-	-	-	✓	✓	✓	✓	✓	✓	✓	-
kubernetes-client 4.9.1	-	-	-	✓	✓	✓	✓	✓	✓	✓	-
kubernetes-client 4.9.2	-	-	-	✓	✓	✓	✓	✓	✓	✓	-
kubernetes-client 4.10.0	-	-	-	✓	✓	✓	✓	✓	✓	✓	✓
kubernetes-client 4.10.1	-	-	-	✓	✓	✓	✓	✓	✓	✓	✓
kubernetes-client 4.10.2	-	-	-	✓	✓	✓	✓	✓	✓	✓	✓
kubernetes-client 4.10.3	-	-	-	✓	✓	✓	✓	✓	✓	✓	✓
kubernetes-client 4.11.0	-	-	-	✓	✓	✓	✓	✓	✓	✓	✓
kubernetes-client 4.11.1	-	-	-	✓	✓	✓	✓	✓	✓	✓	✓

	OpenShift 3.6.0	OpenShift 3.7.0	OpenShift 3.9.0	OpenShift 3.10.0	OpenShift 3.11.0	OpenShift 4.1.0	OpenShift 4.2.0
openshift-client 1.3.92	+	-	-	-	-	-	-
openshift-client 3.0.3	-	✓	-	-	-	-	-
openshift-client 3.0.10	✓	✓	✓	-	-	-	-
openshift-client 3.0.11	✓	✓	✓	-	-	-	-
openshift-client 3.1.12	✓	✓	✓	-	-	-	-
openshift-client 3.2.0	✓	✓	✓	-	-	-	-
openshift-client 4.0.0	✓	✓	✓	-	-	-	-
openshift-client 4.1.0	-	✓	✓	✓	-	-	-
openshift-client 4.1.1	-	-	✓	✓	✓	-	-
openshift-client 4.1.2	-	-	✓	✓	✓	-	-
openshift-client 4.1.3	-	-	✓	✓	✓	-	-
openshift-client 4.2.0	-	-	✓	✓	✓	-	-
openshift-client 4.2.1	-	-	✓	✓	✓	-	-
openshift-client 4.2.2	-	-	✓	✓	✓	-	-
openshift-client 4.3.0	-	-	✓	✓	✓	-	-
openshift-client 4.3.1	-	-	✓	✓	✓	-	-
openshift-client 4.4.0	-	-	✓	✓	✓	✓	-
openshift-client 4.4.1	-	-	✓	✓	✓	✓	-
openshift-client 4.4.2	-	-	✓	✓	✓	✓	-
openshift-client 4.5.0	-	-	✓	✓	✓	✓	-
openshift-client 4.5.1	-	-	✓	✓	✓	✓	-
openshift-client 4.5.2	-	-	✓	✓	✓	✓	-
openshift-client 4.6.0	-	-	✓	✓	✓	✓	-
openshift-client 4.6.1	-	-	✓	✓	✓	✓	-
openshift-client 4.6.2	-	-	✓	✓	✓	✓	-
openshift-client 4.6.3	-	-	✓	✓	✓	✓	-
openshift-client 4.6.4	-	-	✓	✓	✓	✓	-
openshift-client 4.7.0	-	-	✓	✓	✓	✓	✓
openshift-client 4.7.1	-	-	✓	✓	✓	✓	✓
openshift-client 4.8.0	-	-	✓	✓	✓	✓	✓
openshift-client 4.9.0	-	-	✓	✓	✓	✓	✓
openshift-client 4.9.1	-	-	✓	✓	✓	✓	✓
openshift-client 4.9.2	-	-	✓	✓	✓	✓	✓
openshift-client 4.10.0	-	-	✓	✓	✓	✓	✓
openshift-client 4.10.1	-	-	✓	✓	✓	✓	✓
openshift-client 4.10.2	-	-	✓	✓	✓	✓	✓
openshift-client 4.10.3	-	-	✓	✓	✓	✓	✓
openshift-client 4.11.0	-	-	✓	✓	✓	✓	✓
openshift-client 4.11.1	-	-	✓	✓	✓	✓	✓

Major Changes in Kubernetes Client 4.0.0

All the resource objects used here will be according to OpenShift 3.9.0 and Kubernetes 1.9.0. All the resource objects will give all the fields according to OpenShift 3.9.0 and Kubernetes 1.9.0

• SecurityContextConstraints has been moved to OpenShift client from Kubernetes Client
• Job dsl is in both batch and extensions(Extensions is deprecated)
• DaemonSet dsl is in both apps and extensions(Extensions is deprecated)
• Deployment dsl is in both apps and extensions(Extensions is deprecated)
• ReplicaSet dsl is in both apps and extensions(Extensions is deprecated)
• NetworkPolicy dsl is in both network and extensions(Extensions is deprecated)
• Storage Class moved from client base DSL to storage DSL
• PodSecurityPolicies moved from client base DSL and extensions to only extensions
• ThirdPartyResource has been removed.

Who uses Kubernetes & OpenShift Java client?

Extensions:

• Istio API
• Service Catalog API
• Knative
• Tekton

Frameworks/Libraries/Tools:

• Arquillian Cube
• Apache Camel
• Apache Spark
• Jaeger Kubernetes
• Loom
• Microsoft Azure Libraries for Java
• Spinnaker Halyard
• Spring Cloud Connectors for Kubernetes
• Spring Cloud Kubernetes

CI Plugins:

• Deployment Pipeline Plugin (Jenkins)
• Kubernetes Eleastic Agent (GoCD)
• Kubernetes Plugin (Jenkins)
• Kubernetes Pipeline Plugin (Jenkins)
• OpenShift Sync Plugin (Jenkins)
• Kubernetes Plugin (Teamcity from Jetbrains)
• Kubernetes Agents for Bamboo (WindTunnel Technologies)

Build Tools:

• Fabric8 Maven Plugin
• Eclipse JKube
• Gradle Kubernetes Plugin

Platforms:

• Apache Openwhisk
• Eclipse che
• EnMasse
• Openshift.io (Launcher service)
• Spotify Styx
• Strimzi
• Syndesis

Proprietary Platforms:

• vCommander

As our community grows, we would like to track keep track of our users. Please send a PR with your organization/community name.

Tests we run for every new Pull Request

There are the links of the CircleCI and Jenkins for the tests which run for every new Pull Request. You can view all the recent builds also.

• Regression Test
• Unit Test

To get the updates about the releases, you can join https://groups.google.com/forum/embed/?place=forum/fabric8-devclients