Blog

A java example wrapper for creating AMIs in the Amazon EC2

Here is a sample code for creating an AMI from java code, using the Amazon’s EC2 aws-java-sdk. I didn’t manage to find a good “hello world” example for java, so I post my attempt here. I hope that you can kick-start working on the cloud.
First, you create an instance of the wrapper. Then, you can use it for example like: createAMInstances(amiId, 1, 3, “mykey”, “m1.small”, “us-east-1a”);

The above call create 3 small AMIs and a key on the zone us-east-1a. It will create it to your account’s default region (you can modify the code to select also and region).

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.services.ec2.AmazonEC2;
import com.amazonaws.services.ec2.AmazonEC2Client;
import com.amazonaws.services.ec2.model.CreateKeyPairRequest;
import com.amazonaws.services.ec2.model.CreateKeyPairResult;
import com.amazonaws.services.ec2.model.DescribeInstancesResult;
import com.amazonaws.services.ec2.model.Instance;
import com.amazonaws.services.ec2.model.KeyPair;
import com.amazonaws.services.ec2.model.Placement;
import com.amazonaws.services.ec2.model.Reservation;
import com.amazonaws.services.ec2.model.RunInstancesRequest;
import com.amazonaws.services.ec2.model.RunInstancesResult;
import com.amazonaws.services.ec2.model.TerminateInstancesRequest;
import com.amazonaws.services.ec2.model.TerminateInstancesResult;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class EC2_Wrapper {
  private AmazonEC2 ec2;
  private String ReservationId;
  private String instanceId;
  private AWSCredentials credentials;
  /**
   * @return the reservationId
   */
  public String getReservationId() {
    return ReservationId;
  }
  /**
   * @return the instanceId
   */
  public String getInstanceId() {
    return instanceId;
  }
  private KeyPair keyPair;

  public EC2_Wrapper(String accKey, String secKey) throws Exception {
    credentials = new BasicAWSCredentials(accKey, secKey);
    ec2 = new AmazonEC2Client(credentials);
  }

  public String getAMInstanceName() {
    return instanceId;
  }

  public void createAMInstanceSmall(String amiId, String keyPairName)
      throws Exception {
    createAMInstances(amiId, 1, 1, keyPairName, "m1.small", "us-east-1a");
  }

  public void createAMInstances(String AMId, int min, int max,
      String keyPairName, String insType, String availabilityZone)
      throws Exception {
    RunInstancesRequest request = new RunInstancesRequest();
    request.setInstanceType(insType);
    request.setMinCount(min);
    request.setMaxCount(max);
    // set to zone
    Placement p = new Placement();
    p.setAvailabilityZone(availabilityZone);
    request.setPlacement(p);
    request.setImageId(AMId);
    // Create key pair for user..
    CreateKeyPairRequest kpReq = new CreateKeyPairRequest();
    kpReq.setKeyName(keyPairName);
    CreateKeyPairResult kpres = this.ec2.createKeyPair(kpReq);
    keyPair = kpres.getKeyPair();
    System.out.println("You havekeyPair.getKeyName = " + keyPair.getKeyName()
        + "\nkeyPair.getKeyFingerprint()=" + keyPair.getKeyFingerprint()
        + "\nkeyPair.getKeyMaterial()=" + keyPair.getKeyMaterial());
    request.setKeyName(keyPairName); // assign Keypair name for this request
    // request.getSecurityGroups().add("groupname");//create security groups
    // if you want create it! the security group will be default!
    // make sure to have access to SSH port 22 on the default group on the
    // EC2console
    RunInstancesResult runInstancesRes = this.ec2.runInstances(request);
    this.ReservationId = runInstancesRes.getReservation().getReservationId();
    DescribeInstancesResult describeInstancesRequest = ec2.describeInstances();
    List reservations = describeInstancesRequest.getReservations();
    Set instances = new HashSet();

    for (Reservation reservation : reservations) {
      instances.addAll(reservation.getInstances());
      if (reservation.getReservationId().equals(this.ReservationId)) {
        this.instanceId =
            ((Instance) reservation.getInstances().get(0)).getInstanceId();
        System.out.println("this.instanceId = " + this.instanceId);
      }
    }
    System.out.println(
        "You have " + instances.size() + " Amazon EC2 instance(s).");
  }

  public void terminateAMIs() throws Exception {
    try {
      TerminateInstancesRequest rq = new TerminateInstancesRequest();

      rq.getInstanceIds().add(this.instanceId);

      TerminateInstancesResult rsp = this.ec2.terminateInstances(rq);

    } catch (Exception ex) {
      throw ex;
    }
  }
}
Tags: , ,