Remove nodes from a Kubernetes deployment programatically, in order to potentially use the deployment as a pool of ready nodes

KubeConnect.java

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.security.Key;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.UnrecoverableKeyException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

import org.apache.commons.codec.binary.Base64;

import io.fabric8.kubernetes.api.model.Pod;
import io.fabric8.kubernetes.api.model.PodList;

import io.fabric8.kubernetes.client.ConfigBuilder;
import io.fabric8.kubernetes.client.DefaultKubernetesClient;
import io.fabric8.kubernetes.client.KubernetesClient;

public class KubeConnect {
	public static final String K8S_MASTER = "https://kubernetes.master.url/";
	public static final String K8S_NAMESPACE = "some-namespace";
	public static final String K8S_DEPLOYMENT_SELECTOR_LABEL = "app";
	public static final String K8S_DEPLOYMENT_SELECTOR_VALUE = "nginx";
	
	public static final String K8S_PKCS12_CERTIFICATE_LOCATION = "/location/of/certificate.pfx";
	
    private static String pemEncodeKey(Key key) {
        return Base64.encodeBase64String(new StringBuilder() //
                .append("-----BEGIN PRIVATE KEY-----\n") //
                .append(Base64.encodeBase64String(key.getEncoded())) //
                .append("\n-----END PRIVATE KEY-----\n") //
                .toString().getBytes(StandardCharsets.UTF_8));
    }

	public static void main(String[] args) throws KeyStoreException, NoSuchAlgorithmException, CertificateException, IOException, UnrecoverableKeyException {		

	    char[] password = "".toCharArray();  

	    java.io.FileInputStream fis = null;
		KeyStore ks = KeyStore.getInstance("PKCS12");
	    try {
	        fis = new java.io.FileInputStream(KubeConnect.K8S_PKCS12_CERTIFICATE_LOCATION);
	        ks.load(fis, password);
	    } finally {
	        if (fis != null) {
	            fis.close();
	        }
	    }
	    String alias = ks.aliases().nextElement();
        X509Certificate certificate = (X509Certificate) ks.getCertificate(alias);
        Key key = ks.getKey(alias, password);
	    
		ConfigBuilder builder = new ConfigBuilder();
		builder = builder.withMasterUrl(KubeConnect.K8S_MASTER);												
		builder = builder.withNamespace(KubeConnect.K8S_NAMESPACE); 
    builder = builder.withClientCertData(Base64.encodeBase64String(certificate.getEncoded()))
                .withClientKeyData(pemEncodeKey(key))
                .withClientKeyPassphrase(password.toString());

        KubernetesClient kube = new DefaultKubernetesClient(builder.build());
        
        System.out.println("Currently have these pods in the deployment\n");
        PodList pods = kube.pods().withLabel(KubeConnect.K8S_DEPLOYMENT_SELECTOR_LABEL, KubeConnect.K8S_DEPLOYMENT_SELECTOR_VALUE).list();        
        for (Pod pod : pods.getItems()) {
            System.out.println( pod.getMetadata().getName() + ": " + pod.getStatus().getPodIP() );
        }
        
        // Select a pod to remove from deployment
        Pod selected_pod = pods.getItems().get(0);
        System.out.println("Removing this pod from deployment control: " + selected_pod.getMetadata().getName() );
        kube.pods().withName(selected_pod.getMetadata().getName()).edit().editMetadata().removeFromLabels("app").endMetadata().done();
        System.out.println("Removed");
        
        kube.close();
	}
}

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>kubeconnect</groupId>
  <artifactId>kubeconnect</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <build>
    <sourceDirectory>src</sourceDirectory>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.7.0</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
    </plugins>
  </build>
  
  <dependencies>
   <dependency>
            <groupId>io.fabric8</groupId>
            <artifactId>kubernetes-api</artifactId>
            <version>2.2.101</version>
   </dependency> 
   <dependency>
    <groupId>commons-codec</groupId>
    <artifactId>commons-codec</artifactId>
    <version>1.4</version>
  </dependency>    
  </dependencies>
</project>