Kubernetes Java Client

Java client for the kubernetes API.

Client versioning

The Java client uses Semantic Versioning. We increment the major version number whenever we regenerate the client for a new Kubernetes release version (see table below). Whenever we do this there are new APIs added and possibly breaking changes in the generated Kubernetes API Stubs. Whenever you upgrade a major version, be prepared for potential breaking changes.

Installation

To install the Java client library to your local Maven repository, simply execute:

git clone --recursive https://github.com/kubernetes-client/java
cd java
mvn install

Refer to the official documentation for more information.

Maven users

Add this dependency to your project's POM:

<dependency>
    <groupId>io.kubernetes</groupId>
    <artifactId>client-java</artifactId>
    <version>8.0.2</version>
</dependency>

Gradle users

compile 'io.kubernetes:client-java:8.0.2'

Others

At first generate the JAR by executing:

git clone --recursive https://github.com/kubernetes-client/java
cd java/kubernetes
mvn package

Then manually install the following JARs:

• target/client-java-api-8.0.3-SNAPSHOT.jar
• target/lib/*.jar

Example

We prepared a few examples for common use-cases which are shown below:

• Configuration:
  • InClusterClientExample: Configure a client while running inside the Kubernetes cluster.
  • KubeConfigFileClientExample: Configure a client to access a Kubernetes cluster from outside.
• Basics:
  • SimpleExample: Simple minimum example of how to use the client.
  • ProtoExample: Request/receive payloads in protobuf serialization protocol.
  • (5.0.0+) PatchExample: Patch resource objects in various supported patch formats, equal to kubectl patch.
  • FluentExample: Construct arbitrary resource in a fluent builder style.
  • YamlExample: Suggested way to load or dump resource in Yaml.
• Streaming:
  • WatchExample: Subscribe watch events from certain resources, equal to kubectl get <resource> -w.
  • LogsExample: Fetch logs from running containers, equal to kubectl logs.
  • ExecExample: Establish an "exec" session with running containers, equal to kubectl exec.
  • PortForwardExample: Maps local port to a port on the pod, equal to kubectl port-forward.
  • AttachExample: Attach to a process that is already running inside an existing container, equal to kubectl attach.
  • CopyExample: Copy files and directories to and from containers, equal to kubectl cp.
  • WebSocketsExample: Establish an arbitrary web-socket session to certain resources.
• Advanced: (NOTE: The following example requires client-java-extended module）
  • (5.0.0+) InformerExample: Build an informer which list-watches resources and reflects the notifications to a local cache.
  • (5.0.0+) PagerExample: Support Pagination (only for the list request) to ease server-side loads/network congestion.
  • (6.0.0+) ControllerExample: Build a controller reconciling the state of world by list-watching one or multiple resources.
  • (6.0.0+) LeaderElectionExample: Leader election utilities to help implement HA controllers.
  • (9.0.0+) SpringIntegrationControllerExample: Building a kubernetes controller based on spring framework's bean injection.
  • (9.0.0+) GenericKubernetesClientExample: Construct a generic client interface for any kubernetes types, including CRDs.

list all pods:

import io.kubernetes.client.openapi.ApiClient;
import io.kubernetes.client.openapi.ApiException;
import io.kubernetes.client.openapi.Configuration;
import io.kubernetes.client.openapi.apis.CoreV1Api;
import io.kubernetes.client.openapi.models.V1Pod;
import io.kubernetes.client.openapi.models.V1PodList;
import io.kubernetes.client.util.Config;

import java.io.IOException;

public class Example {
    public static void main(String[] args) throws IOException, ApiException{
        ApiClient client = Config.defaultClient();
        Configuration.setDefaultApiClient(client);