Managing clusters using the Amazon SDK for Java - Amazon Redshift
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Managing clusters using the Amazon SDK for Java

The following Java code example demonstrates common cluster management operations including:

  • Creating a cluster.

  • Listing metadata about a cluster.

  • Modifying configuration options.

After you initiate the request for the cluster to be created, you must wait until the cluster is in the available state before you can modify it. This example uses a loop to periodically check the status of the cluster using the describeClusters method. When the cluster is available, the preferred maintenance window for the cluster is changed.

For step-by-step instructions to run the following example, see Running Java examples for Amazon Redshift using Eclipse. You need to update the code and specify a cluster identifier.

/**
 * Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * This file is licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License. A copy of
 * the License is located at
 *
 * http://aws.amazon.com/apache2.0/
 *
 * This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
 * CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */

// snippet-sourcedescription:[CreateAndModifyCluster demonstrates how to create and modify an Amazon Redshift cluster.]
// snippet-service:[redshift]
// snippet-keyword:[Java]
// snippet-keyword:[Amazon Redshift]
// snippet-keyword:[Code Sample]
// snippet-keyword:[CreateCluster]
// snippet-keyword:[DescribeClusters]
// snippet-keyword:[ModifyCluster]
// snippet-sourcetype:[full-example]
// snippet-sourcedate:[2019-02-01]
// snippet-sourceauthor:[AWS]
// snippet-start:[redshift.java.CreateAndModifyCluster.complete]

package com.amazonaws.services.redshift;

import java.io.IOException;

import com.amazonaws.services.redshift.AmazonRedshift;
import com.amazonaws.services.redshift.AmazonRedshiftClientBuilder;
import com.amazonaws.services.redshift.model.*;

public class CreateAndModifyCluster {

    public static AmazonRedshift client;
    public static String clusterIdentifier = "***provide a cluster identifier***";
    public static long sleepTime = 20;

    public static void main(String[] args) throws IOException {

        // Default client using the {@link com.amazonaws.auth.DefaultAWSCredentialsProviderChain}
        client = AmazonRedshiftClientBuilder.defaultClient();

        try {
            createCluster();
            waitForClusterReady();
            describeClusters();
            modifyCluster();
            describeClusters();
        } catch (Exception e) {
            System.err.println("Operation failed: " + e.getMessage());
        }
    }

    private static void createCluster() {
        CreateClusterRequest request = new CreateClusterRequest()
                .withClusterIdentifier(clusterIdentifier)
                .withMasterUsername("masteruser")
                .withMasterUserPassword("12345678Aa")
                .withNodeType("ds2.xlarge")
                .withNumberOfNodes(2)
                .withClusterSubnetGroupName("subnetgroup1");


        Cluster createResponse = client.createCluster(request);
        System.out.println("Created cluster " + createResponse.getClusterIdentifier());
    }

    private static void describeClusters() {
        DescribeClustersRequest request = new DescribeClustersRequest()
                .withClusterIdentifier(clusterIdentifier);

        DescribeClustersResult result = client.describeClusters(request);
        printResult(result);
    }

    private static void modifyCluster() {
        ModifyClusterRequest request = new ModifyClusterRequest()
                .withClusterIdentifier(clusterIdentifier)
                .withPreferredMaintenanceWindow("wed:07:30-wed:08:00");

        client.modifyCluster(request);
        System.out.println("Modified cluster " + clusterIdentifier);

    }

    private static void printResult(DescribeClustersResult result)
    {
        if (result == null)
        {
            System.out.println("Describe clusters result is null.");
            return;
        }

        System.out.println("Cluster property:");
        System.out.format("Preferred Maintenance Window: %s\n", result.getClusters().get(0).getPreferredMaintenanceWindow());
    }

    private static void waitForClusterReady() throws InterruptedException {
        Boolean clusterReady = false;
        System.out.println("Wating for cluster to become available.");
        while (!clusterReady) {
            DescribeClustersResult result = client.describeClusters(new DescribeClustersRequest()
                                                                            .withClusterIdentifier(clusterIdentifier));
            String status = (result.getClusters()).get(0).getClusterStatus();
            if (status.equalsIgnoreCase("available")) {
                clusterReady = true;
            }
            else {
                System.out.print(".");
                Thread.sleep(sleepTime*1000);
            }
        }
    }
}
// snippet-end:[redshift.java.CreateAndModifyCluster.complete]