Ejemplo n.º 1
0
  public static void main(String[] args) throws UnknownHostException {
    AmazonEC2 ec2 = new AmazonEC2Client(new ClasspathPropertiesFileCredentialsProvider());
    Region usWest2 = Region.getRegion(Regions.US_WEST_2);
    ec2.setRegion(usWest2);
    List<String> instanceIds = new ArrayList<>();
    String instanceid = null;
    DescribeInstancesRequest request = new DescribeInstancesRequest();

    List<String> valuesT1 = new ArrayList<String>();
    valuesT1.add("hz-nodes");
    Filter filter = new Filter("tag-value", valuesT1);

    DescribeInstancesResult result = ec2.describeInstances(request.withFilters(filter));

    List<Reservation> reservations = result.getReservations();

    for (Reservation reservation : reservations) {
      List<Instance> instances = reservation.getInstances();
      for (Instance instance : instances) {
        instanceid = instance.getInstanceId();
        PrintManager.PrintMessage(instanceid);
        instanceIds.add(instanceid);
        List<Tag> abc = instance.getTags();
        for (Tag aaa : abc) {
          PrintManager.PrintMessage(aaa.getKey() + " : " + aaa.getValue());
        }
      }
    }
    instanceIds.remove("i-cb45adfc");
    StopInstancesRequest stopReq = new StopInstancesRequest(instanceIds);
    ec2.stopInstances(stopReq);
    RebootInstancesRequest requestRe = new RebootInstancesRequest(instanceIds);
    ec2.rebootInstances(requestRe);
  }
Ejemplo n.º 2
0
 /**
  * Counts the number of instances in EC2 currently running that are using the specified image and
  * a template.
  *
  * @param ami If AMI is left null, then all instances are counted and template description is
  *     ignored.
  *     <p>This includes those instances that may be started outside Jenkins.
  * @param templateDesc
  */
 public int countCurrentEC2Slaves(String ami, String templateDesc) throws AmazonClientException {
   int n = 0;
   for (Reservation r : connect().describeInstances().getReservations()) {
     for (Instance i : r.getInstances()) {
       if (isEc2ProvisionedAmiSlave(i, ami, templateDesc)) {
         InstanceStateName stateName = InstanceStateName.fromValue(i.getState().getName());
         if (stateName == InstanceStateName.Pending || stateName == InstanceStateName.Running) {
           EC2AbstractSlave foundSlave = null;
           for (EC2AbstractSlave ec2Node : NodeIterator.nodes(EC2AbstractSlave.class)) {
             if (ec2Node.getInstanceId().equals(i.getInstanceId())) {
               foundSlave = ec2Node;
               break;
             }
           }
           // Don't count disconnected slaves as being used, we will connected them later is
           // required
           if (foundSlave != null && foundSlave.toComputer().isOffline()) continue;
           n++;
         }
       }
     }
   }
   // Count pending spot requests too
   for (SpotInstanceRequest sir :
       connect().describeSpotInstanceRequests().getSpotInstanceRequests()) {
     // Count Spot requests that are open and still have a
     // chance to be active.
     if (sir.getState().equals("open")) {
       n++;
     }
   }
   return n;
 }
Ejemplo n.º 3
0
 public void run() {
   LOG.debug("Running describeInstances() in " + region.getRegionName());
   List<Reservation> reservations = ec2Client.describeInstances().getReservations();
   for (Reservation reservation : reservations) {
     instances.addAll(reservation.getInstances());
   }
   LOG.debug("Completed describeInstances() in " + region.getRegionName());
 }
 public String getDnsMaster(String clusterId) {
   String master = null;
   DescribeInstancesResult describeInstancesRequest = ec2.describeInstances();
   List<Reservation> reservations = describeInstancesRequest.getReservations();
   int count = 0;
   for (Reservation reservation : reservations) {
     List<com.amazonaws.services.ec2.model.Tag> tags = reservation.getInstances().get(0).getTags();
     for (int i = 0; i < tags.size(); i++) {
       if ((tags.get(i).getValue().equals(clusterId))
           || (tags.get(i).getValue().equals("MASTER"))) {
         count++;
       }
     }
     if (count == 2) master = reservation.getInstances().get(0).getPublicDnsName();
     count = 0;
   }
   return master;
 }
  public static String getPublicDns(String instanceId) {

    System.out.println("Retreiving public dns.");

    DescribeInstancesResult results = ec2.describeInstances();
    List<Reservation> reservations = results.getReservations();

    for (Reservation reservation : reservations) {
      for (Instance instance : reservation.getInstances()) {
        if (instance.getInstanceId().equals(instanceId)) return instance.getPublicDnsName();
      }
    }
    return "NA";
  }
  /** Query amazon to get ASG name. Currently not available as part of instance info api. */
  private String populateASGName(String region, String instanceId) {
    AmazonEC2 client = new AmazonEC2Client(provider.getCredentials());
    client.setEndpoint("ec2." + region + ".amazonaws.com");
    DescribeInstancesRequest desc = new DescribeInstancesRequest().withInstanceIds(instanceId);
    DescribeInstancesResult res = client.describeInstances(desc);

    for (Reservation resr : res.getReservations()) {
      for (Instance ins : resr.getInstances()) {
        for (com.amazonaws.services.ec2.model.Tag tag : ins.getTags()) {
          if (tag.getKey().equals("aws:autoscaling:groupName")) return tag.getValue();
        }
      }
    }
    return null;
  }
Ejemplo n.º 7
0
    @Override
    public String retriableCall() throws IllegalStateException {
      DescribeInstancesRequest desc = new DescribeInstancesRequest().withInstanceIds(instanceId);
      DescribeInstancesResult res = client.describeInstances(desc);

      for (Reservation resr : res.getReservations()) {
        for (Instance ins : resr.getInstances()) {
          for (com.amazonaws.services.ec2.model.Tag tag : ins.getTags()) {
            if (tag.getKey().equals("aws:autoscaling:groupName")) return tag.getValue();
          }
        }
      }

      logger.warn("Couldn't determine ASG name");
      throw new IllegalStateException("Couldn't determine ASG name");
    }
Ejemplo n.º 8
0
  public Instance startInstance(AWSCredentials credentials) {
    AmazonEC2Client amazonEC2Client = new AmazonEC2Client(credentials);

    RunInstancesRequest runInstancesRequest =
        new RunInstancesRequest()
            .withImageId("")
            .withInstanceType("m1.small")
            .withMinCount(1)
            .withMaxCount(1);

    RunInstancesResult runInstancesResult = amazonEC2Client.runInstances(runInstancesRequest);

    Reservation reservation = runInstancesResult.getReservation();
    List<Instance> instances = reservation.getInstances();

    // there will be exactly one instance in this list, otherwise
    // runInstances() would have thrown an exception
    return instances.get(0);
  }
Ejemplo n.º 9
0
  private static void putCache() throws CacheException {
    if (amazon == null) amazon = JCS.getInstance("Instances");
    synchronized (AmazonService.class) {
      amazon.clear();
      DescribeInstancesResult result = amazonClient.describeInstances();
      for (Reservation r : result.getReservations()) {
        for (Instance i : r.getInstances()) {
          amazon.putInGroup(i.getInstanceId(), "Instances", i);
        }
      }

      DescribeImagesRequest ir = new DescribeImagesRequest().withOwners("self");
      DescribeImagesResult images = amazonClient.describeImages(ir);
      for (Image r : images.getImages()) {
        amazon.putInGroup(r.getImageId(), "AMIs", r);
      }
      log.debug("put cache finished");
    }
  }
Ejemplo n.º 10
0
  /**
   * Describe a set of specific instances.
   *
   * @param instanceIds the instance ids
   * @return the instances
   */
  public List<Instance> describeInstances(String... instanceIds) {
    if (instanceIds == null || instanceIds.length == 0) {
      LOGGER.info("Getting all EC2 instances.");
    } else {
      LOGGER.info(String.format("Getting EC2 instances for %d ids.", instanceIds.length));
    }

    List<Instance> instances = new LinkedList<Instance>();

    AmazonEC2 ec2Client = ec2Client();
    DescribeInstancesRequest request = new DescribeInstancesRequest();
    if (instanceIds != null) {
      request.withInstanceIds(Arrays.asList(instanceIds));
    }
    DescribeInstancesResult result = ec2Client.describeInstances(request);
    for (Reservation reservation : result.getReservations()) {
      instances.addAll(reservation.getInstances());
    }

    LOGGER.info(String.format("Got %d EC2 instances.", instances.size()));
    return instances;
  }
Ejemplo n.º 11
0
  // Returns pending/running instance ID list.
  public static ArrayList<String> getInstanceIdsByTag(AmazonEC2 ec2, String key, String value) {
    logger.fine("Requesting instances by tag " + key + "=" + value);

    // Create tag request.
    DescribeInstancesRequest instanceReq = new DescribeInstancesRequest();
    Filter managerFilter = new Filter("tag:" + key).withValues(value),
        activeFilter =
            new Filter("instance-state-code").withValues("0", "16"); // 0||16 == pending||running

    // Send request.
    DescribeInstancesResult result =
        ec2.describeInstances(instanceReq.withFilters(managerFilter, activeFilter));

    // Build instance ID list.
    ArrayList<String> ids = new ArrayList<String>();
    for (Reservation reservation : result.getReservations()) {
      for (Instance instance : reservation.getInstances()) {
        ids.add(instance.getInstanceId());
      }
    }

    logger.fine(ids.size() + " instances found with tag " + key + "=" + value);
    return ids;
  }
Ejemplo n.º 12
0
  public static void main(String[] args) throws Exception {
    System.out.println("===========================================");
    System.out.println("Welcome to the AWS Java SDK!");
    System.out.println("===========================================");

    init();

    try {
      /*
       * The Amazon EC2 client allows you to easily launch and configure
       * computing capacity in AWS datacenters.
       *
       * In this sample, we use the EC2 client to list the availability zones
       * in a region, and then list the instances running in those zones.
       */
      DescribeAvailabilityZonesResult availabilityZonesResult = ec2.describeAvailabilityZones();
      List<AvailabilityZone> availabilityZones = availabilityZonesResult.getAvailabilityZones();
      System.out.println("You have access to " + availabilityZones.size() + " availability zones:");
      for (AvailabilityZone zone : availabilityZones) {
        System.out.println(" - " + zone.getZoneName() + " (" + zone.getRegionName() + ")");
      }

      DescribeInstancesResult describeInstancesResult = ec2.describeInstances();
      Set<Instance> instances = new HashSet<Instance>();
      for (Reservation reservation : describeInstancesResult.getReservations()) {
        instances.addAll(reservation.getInstances());
      }

      System.out.println("You have " + instances.size() + " Amazon EC2 instance(s) running.");

      /*
       * The Amazon S3 client allows you to manage and configure buckets
       * and to upload and download data.
       *
       * In this sample, we use the S3 client to list all the buckets in
       * your account, and then iterate over the object metadata for all
       * objects in one bucket to calculate the total object count and
       * space usage for that one bucket. Note that this sample only
       * retrieves the object's metadata and doesn't actually download the
       * object's content.
       *
       * In addition to the low-level Amazon S3 client in the SDK, there
       * is also a high-level TransferManager API that provides
       * asynchronous management of uploads and downloads with an easy to
       * use API:
       *   http://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/services/s3/transfer/TransferManager.html
       */
      List<Bucket> buckets = s3.listBuckets();
      System.out.println("You have " + buckets.size() + " Amazon S3 bucket(s).");

      if (buckets.size() > 0) {
        Bucket bucket = buckets.get(0);

        long totalSize = 0;
        long totalItems = 0;
        /*
         * The S3Objects and S3Versions classes provide convenient APIs
         * for iterating over the contents of your buckets, without
         * having to manually deal with response pagination.
         */
        for (S3ObjectSummary objectSummary : S3Objects.inBucket(s3, bucket.getName())) {
          totalSize += objectSummary.getSize();
          totalItems++;
        }

        System.out.println(
            "The bucket '"
                + bucket.getName()
                + "' contains "
                + totalItems
                + " objects "
                + "with a total size of "
                + totalSize
                + " bytes.");
      }
    } catch (AmazonServiceException ase) {
      /*
       * AmazonServiceExceptions represent an error response from an AWS
       * services, i.e. your request made it to AWS, but the AWS service
       * either found it invalid or encountered an error trying to execute
       * it.
       */
      System.out.println("Error Message:    " + ase.getMessage());
      System.out.println("HTTP Status Code: " + ase.getStatusCode());
      System.out.println("AWS Error Code:   " + ase.getErrorCode());
      System.out.println("Error Type:       " + ase.getErrorType());
      System.out.println("Request ID:       " + ase.getRequestId());
    } catch (AmazonClientException ace) {
      /*
       * AmazonClientExceptions represent an error that occurred inside
       * the client on the local host, either while trying to send the
       * request to AWS or interpret the response. For example, if no
       * network connection is available, the client won't be able to
       * connect to AWS to execute a request and will throw an
       * AmazonClientException.
       */
      System.out.println("Error Message: " + ace.getMessage());
    }
  }
Ejemplo n.º 13
0
  /**
   * Provisions an On-demand EC2 slave by launching a new instance or starting a previously-stopped
   * instance.
   */
  private EC2AbstractSlave provisionOndemand(
      TaskListener listener, Label requiredLabel, EnumSet<ProvisionOptions> provisionOptions)
      throws AmazonClientException, IOException {
    PrintStream logger = listener.getLogger();
    AmazonEC2 ec2 = getParent().connect();

    try {
      logProvisionInfo(logger, "Considering launching " + ami + " for template " + description);

      KeyPair keyPair = getKeyPair(ec2);

      RunInstancesRequest riRequest = new RunInstancesRequest(ami, 1, 1);
      InstanceNetworkInterfaceSpecification net = new InstanceNetworkInterfaceSpecification();

      riRequest.setEbsOptimized(ebsOptimized);

      if (useEphemeralDevices) {
        setupEphemeralDeviceMapping(riRequest);
      } else {
        setupCustomDeviceMapping(riRequest);
      }

      if (stopOnTerminate) {
        riRequest.setInstanceInitiatedShutdownBehavior(ShutdownBehavior.Stop);
        logProvisionInfo(
            logger, "Setting Instance Initiated Shutdown Behavior : ShutdownBehavior.Stop");
      } else {
        riRequest.setInstanceInitiatedShutdownBehavior(ShutdownBehavior.Terminate);
        logProvisionInfo(
            logger, "Setting Instance Initiated Shutdown Behavior : ShutdownBehavior.Terminate");
      }

      List<Filter> diFilters = new ArrayList<Filter>();
      diFilters.add(new Filter("image-id").withValues(ami));

      if (StringUtils.isNotBlank(getZone())) {
        Placement placement = new Placement(getZone());
        if (getUseDedicatedTenancy()) {
          placement.setTenancy("dedicated");
        }
        riRequest.setPlacement(placement);
        diFilters.add(new Filter("availability-zone").withValues(getZone()));
      }

      if (StringUtils.isNotBlank(getSubnetId())) {
        if (getAssociatePublicIp()) {
          net.setSubnetId(getSubnetId());
        } else {
          riRequest.setSubnetId(getSubnetId());
        }

        diFilters.add(new Filter("subnet-id").withValues(getSubnetId()));

        /*
         * If we have a subnet ID then we can only use VPC security groups
         */
        if (!securityGroupSet.isEmpty()) {
          List<String> groupIds = getEc2SecurityGroups(ec2);

          if (!groupIds.isEmpty()) {
            if (getAssociatePublicIp()) {
              net.setGroups(groupIds);
            } else {
              riRequest.setSecurityGroupIds(groupIds);
            }

            diFilters.add(new Filter("instance.group-id").withValues(groupIds));
          }
        }
      } else {
        /* No subnet: we can use standard security groups by name */
        riRequest.setSecurityGroups(securityGroupSet);
        if (!securityGroupSet.isEmpty()) {
          diFilters.add(new Filter("instance.group-name").withValues(securityGroupSet));
        }
      }

      String userDataString = Base64.encodeBase64String(userData.getBytes(StandardCharsets.UTF_8));
      riRequest.setUserData(userDataString);
      riRequest.setKeyName(keyPair.getKeyName());
      diFilters.add(new Filter("key-name").withValues(keyPair.getKeyName()));
      riRequest.setInstanceType(type.toString());
      diFilters.add(new Filter("instance-type").withValues(type.toString()));

      if (getAssociatePublicIp()) {
        net.setAssociatePublicIpAddress(true);
        net.setDeviceIndex(0);
        riRequest.withNetworkInterfaces(net);
      }

      boolean hasCustomTypeTag = false;
      HashSet<Tag> instTags = null;
      if (tags != null && !tags.isEmpty()) {
        instTags = new HashSet<Tag>();
        for (EC2Tag t : tags) {
          instTags.add(new Tag(t.getName(), t.getValue()));
          diFilters.add(new Filter("tag:" + t.getName()).withValues(t.getValue()));
          if (StringUtils.equals(t.getName(), EC2Tag.TAG_NAME_JENKINS_SLAVE_TYPE)) {
            hasCustomTypeTag = true;
          }
        }
      }
      if (!hasCustomTypeTag) {
        if (instTags == null) {
          instTags = new HashSet<Tag>();
        }
        // Append template description as well to identify slaves provisioned per template
        instTags.add(
            new Tag(
                EC2Tag.TAG_NAME_JENKINS_SLAVE_TYPE,
                EC2Cloud.getSlaveTypeTagValue(EC2Cloud.EC2_SLAVE_TYPE_DEMAND, description)));
      }

      DescribeInstancesRequest diRequest = new DescribeInstancesRequest();
      diRequest.setFilters(diFilters);

      logProvision(logger, "Looking for existing instances with describe-instance: " + diRequest);

      DescribeInstancesResult diResult = ec2.describeInstances(diRequest);
      EC2AbstractSlave[] ec2Node = new EC2AbstractSlave[1];
      Instance existingInstance = null;
      if (!provisionOptions.contains(ProvisionOptions.FORCE_CREATE)) {
        reservationLoop:
        for (Reservation reservation : diResult.getReservations()) {
          for (Instance instance : reservation.getInstances()) {
            if (checkInstance(logger, instance, requiredLabel, ec2Node)) {
              existingInstance = instance;
              logProvision(
                  logger,
                  "Found existing instance: "
                      + existingInstance
                      + ((ec2Node[0] != null) ? (" node: " + ec2Node[0].getInstanceId()) : ""));
              break reservationLoop;
            }
          }
        }
      }

      if (existingInstance == null) {
        if (!provisionOptions.contains(ProvisionOptions.FORCE_CREATE)
            && !provisionOptions.contains(ProvisionOptions.ALLOW_CREATE)) {
          logProvision(logger, "No existing instance found - but cannot create new instance");
          return null;
        }
        if (StringUtils.isNotBlank(getIamInstanceProfile())) {
          riRequest.setIamInstanceProfile(
              new IamInstanceProfileSpecification().withArn(getIamInstanceProfile()));
        }
        // Have to create a new instance
        Instance inst = ec2.runInstances(riRequest).getReservation().getInstances().get(0);

        /* Now that we have our instance, we can set tags on it */
        if (instTags != null) {
          updateRemoteTags(ec2, instTags, "InvalidInstanceID.NotFound", inst.getInstanceId());

          // That was a remote request - we should also update our
          // local instance data.
          inst.setTags(instTags);
        }
        logProvisionInfo(logger, "No existing instance found - created new instance: " + inst);
        return newOndemandSlave(inst);
      }

      if (existingInstance
              .getState()
              .getName()
              .equalsIgnoreCase(InstanceStateName.Stopping.toString())
          || existingInstance
              .getState()
              .getName()
              .equalsIgnoreCase(InstanceStateName.Stopped.toString())) {

        List<String> instances = new ArrayList<String>();
        instances.add(existingInstance.getInstanceId());
        StartInstancesRequest siRequest = new StartInstancesRequest(instances);
        StartInstancesResult siResult = ec2.startInstances(siRequest);

        logProvisionInfo(
            logger,
            "Found stopped instance - starting it: " + existingInstance + " result:" + siResult);
      } else {
        // Should be pending or running at this point, just let it come up
        logProvisionInfo(
            logger,
            "Found existing pending or running: "
                + existingInstance.getState().getName()
                + " instance: "
                + existingInstance);
      }

      if (ec2Node[0] != null) {
        logProvisionInfo(logger, "Using existing slave: " + ec2Node[0].getInstanceId());
        return ec2Node[0];
      }

      // Existing slave not found
      logProvision(logger, "Creating new slave for existing instance: " + existingInstance);
      return newOndemandSlave(existingInstance);

    } catch (FormException e) {
      throw new AssertionError(e); // we should have discovered all
      // configuration issues upfront
    } catch (InterruptedException e) {
      throw new RuntimeException(e);
    }
  }
  @Override
  public List<DiscoveryNode> buildDynamicNodes() {
    List<DiscoveryNode> discoNodes = new ArrayList<>();

    DescribeInstancesResult descInstances;
    try {
      // Query EC2 API based on AZ, instance state, and tag.

      // NOTE: we don't filter by security group during the describe instances request for two
      // reasons:
      // 1. differences in VPCs require different parameters during query (ID vs Name)
      // 2. We want to use two different strategies: (all security groups vs. any security groups)
      descInstances = client.describeInstances(buildDescribeInstancesRequest());
    } catch (AmazonClientException e) {
      logger.info("Exception while retrieving instance list from AWS API: {}", e.getMessage());
      logger.debug("Full exception:", e);
      return discoNodes;
    }

    logger.trace("building dynamic unicast discovery nodes...");
    for (Reservation reservation : descInstances.getReservations()) {
      for (Instance instance : reservation.getInstances()) {
        // lets see if we can filter based on groups
        if (!groups.isEmpty()) {
          List<GroupIdentifier> instanceSecurityGroups = instance.getSecurityGroups();
          ArrayList<String> securityGroupNames = new ArrayList<String>();
          ArrayList<String> securityGroupIds = new ArrayList<String>();
          for (GroupIdentifier sg : instanceSecurityGroups) {
            securityGroupNames.add(sg.getGroupName());
            securityGroupIds.add(sg.getGroupId());
          }
          if (bindAnyGroup) {
            // We check if we can find at least one group name or one group id in groups.
            if (Collections.disjoint(securityGroupNames, groups)
                && Collections.disjoint(securityGroupIds, groups)) {
              logger.trace(
                  "filtering out instance {} based on groups {}, not part of {}",
                  instance.getInstanceId(),
                  instanceSecurityGroups,
                  groups);
              // continue to the next instance
              continue;
            }
          } else {
            // We need tp match all group names or group ids, otherwise we ignore this instance
            if (!(securityGroupNames.containsAll(groups) || securityGroupIds.containsAll(groups))) {
              logger.trace(
                  "filtering out instance {} based on groups {}, does not include all of {}",
                  instance.getInstanceId(),
                  instanceSecurityGroups,
                  groups);
              // continue to the next instance
              continue;
            }
          }
        }

        String address = null;
        switch (hostType) {
          case PRIVATE_DNS:
            address = instance.getPrivateDnsName();
            break;
          case PRIVATE_IP:
            address = instance.getPrivateIpAddress();
            break;
          case PUBLIC_DNS:
            address = instance.getPublicDnsName();
            break;
          case PUBLIC_IP:
            address = instance.getPublicIpAddress();
            break;
        }
        if (address != null) {
          try {
            TransportAddress[] addresses = transportService.addressesFromString(address);
            // we only limit to 1 addresses, makes no sense to ping 100 ports
            for (int i = 0; (i < addresses.length && i < UnicastZenPing.LIMIT_PORTS_COUNT); i++) {
              logger.trace(
                  "adding {}, address {}, transport_address {}",
                  instance.getInstanceId(),
                  address,
                  addresses[i]);
              discoNodes.add(
                  new DiscoveryNode(
                      "#cloud-" + instance.getInstanceId() + "-" + i,
                      addresses[i],
                      version.minimumCompatibilityVersion()));
            }
          } catch (Exception e) {
            logger.warn("failed ot add {}, address {}", e, instance.getInstanceId(), address);
          }
        } else {
          logger.trace(
              "not adding {}, address is null, host_type {}", instance.getInstanceId(), hostType);
        }
      }
    }

    logger.debug("using dynamic discovery nodes {}", discoNodes);

    return discoNodes;
  }
Ejemplo n.º 15
0
  public void run() {
    logger.debug("started GridManager");
    System.out.println("started GridManager");
    AmazonSQSClient sqsClient = new AmazonSQSClient(papa.getCredentials());
    AmazonEC2Client ec2Client = new AmazonEC2Client(papa.getCredentials());

    // Get current imageID from the metadata table
    String imageID = Constants.imageID; // get the default imageID from Constants
    try {
      Connection conn = PooledConnectionFactory.INSTANCE.getCumulusConnection();
      Statement stmt = conn.createStatement();
      String imageQuery = "SELECT mvalue FROM cumulus.metadata WHERE mkey='imageID';";
      ResultSet results = stmt.executeQuery(imageQuery);
      results.next(); // move the cursor into the results
      imageID = results.getString(1);
    } catch (SQLException e) {
      logger.warn(e);
    }
    if (imageID == null
        || imageID.equals("")) { // if we get an empty imageID revert to the hardcoded one
      imageID = Constants.imageID;
    }
    logger.debug(imageID);
    System.out.println(imageID);

    while (true) { // loop from startup to shutdown
      // check the number of messages in the queue.
      GetQueueAttributesRequest sqsRequest =
          new GetQueueAttributesRequest(papa.getDispatchQueue())
              .withAttributeNames("ApproximateNumberOfMessages");
      Integer sqsResult = null;
      try {
        sqsResult =
            Integer.valueOf(
                sqsClient
                    .getQueueAttributes(sqsRequest)
                    .getAttributes()
                    .get("ApproximateNumberOfMessages"));
      } catch (AmazonServiceException e) {
        // Write out any exceptions that may have occurred.
        System.err.println("Error getting list of instances");
        System.err.println("Caught Exception: " + e.getMessage());
        System.err.println("Reponse Status Code: " + e.getStatusCode());
        System.err.println("Error Code: " + e.getErrorCode());
        System.err.println("Request ID: " + e.getRequestId());
      } catch (AmazonClientException e) {
        logger.warn(e);
        continue; // if the error is due to being unable to connect to sqs it is likely transient,
                  // and we should keep going until SQS comes back
      } catch (Exception e) {
        // caught another exception
        System.err.println(e);
        System.err.println("Did not exit cleanly");
        // System.exit(1);
      }
      if (sqsResult == null) {
        System.err.println(
            "Couldn't get the number of items in the queue reverting to static functioning");
        logger.error(
            "Couldn't get the number of items in the queue reverting to static functioning");
        break;
      }
      System.out.println("Queue size=" + sqsResult);
      // check the number of running instances.
      DescribeInstancesRequest describeInstancesRequest = new DescribeInstancesRequest();
      // get the number of running instances with our image ID
      describeInstancesRequest.withFilters(
          new Filter("image-id").withValues(imageID),
          new Filter("instance-state-name").withValues("running"));
      logger.debug("Getting list of active cumulus drones");
      Integer numInstances = null;
      Integer numSpotRequests = null;
      Initializer.serialize("/tmp/dump.obj", papa.unitsOnServer); // TODO test this.
      // check number of open spot requests
      DescribeSpotInstanceRequestsRequest describeSpotInstancesRequest =
          new DescribeSpotInstanceRequestsRequest();
      describeSpotInstancesRequest.withFilters(new Filter("state").withValues("open"));
      try {
        // Parse returned instances
        DescribeInstancesResult describeInstancesResult =
            ec2Client.describeInstances(describeInstancesRequest);
        if (describeInstancesResult.getReservations().size() == 0) {
          numInstances = 0;
        } else {
          Integer totalInstances = 0;
          for (Reservation i : describeInstancesResult.getReservations()) {
            totalInstances += i.getInstances().size();
          }
          numInstances = totalInstances;
        }
        // Parse returned open spot requests
        DescribeSpotInstanceRequestsResult describeSpotReservationsResult =
            ec2Client.describeSpotInstanceRequests(describeSpotInstancesRequest);
        if (describeSpotReservationsResult.getSpotInstanceRequests().size() == 0) {
          numSpotRequests = 0;
        } else {
          Integer totalInstances = 0;
          for (SpotInstanceRequest i : describeSpotReservationsResult.getSpotInstanceRequests()) {
            totalInstances++;
          }
          numSpotRequests = totalInstances;
        }

        // System.out.println("num instances="+numInstances);
      } catch (AmazonServiceException e) {
        // Write out any exceptions that may have occurred.
        System.err.println("Error getting list of instances");
        System.err.println("Caught Exception: " + e.getMessage());
        System.err.println("Reponse Status Code: " + e.getStatusCode());
        System.err.println("Error Code: " + e.getErrorCode());
        System.err.println("Request ID: " + e.getRequestId());
        // System.exit(1);
      } catch (Exception e) {
        // caught another exception
        System.err.println(e);
        System.err.println("Did not exit cleanly");
        // System.exit(1);
      }
      if (numInstances == null || numSpotRequests == null) {
        logger.error(
            "Couldn't get the number of machines or requests reverting to static functioning");
        break;
      }
      System.out.println("num instances=" + (numInstances + numSpotRequests));

      // if queue is longer than the number of instances * idealMaxUnitsPerInstance
      Integer idealMaxUnitsPerInstance = Integer.valueOf(Constants.idealMaxUnitsPerInstance);
      if (sqsResult
          > (numInstances + numSpotRequests)
              * idealMaxUnitsPerInstance) { // we count pending spot instances too.
        Integer numToCreate = (sqsResult / idealMaxUnitsPerInstance) - numInstances + 1;
        // check current pricing of spot instances
        DescribeSpotPriceHistoryRequest historyRequest =
            new DescribeSpotPriceHistoryRequest()
                .withAvailabilityZone("us-east-1c")
                .withInstanceTypes(Constants.instanceType)
                .withProductDescriptions("Linux/UNIX (Amazon VPC)")
                .withStartTime(new Date(System.currentTimeMillis()));
        DescribeSpotPriceHistoryResult result = ec2Client.describeSpotPriceHistory(historyRequest);
        Double nowPrice = Double.valueOf(result.getSpotPriceHistory().get(0).getSpotPrice());
        // If spot price is < constants.spotPrice launch numToCreate*Constants.percentSpot spot
        // instances
        Integer spotToCreate = 0;
        if (nowPrice < Double.valueOf(Constants.spotPrice)) {
          Double percentSpot = Double.valueOf(Constants.percentSpot);
          spotToCreate = (int) (numToCreate * percentSpot);
          numToCreate = (int) (numToCreate * (1 - percentSpot));
        }
        try {
          System.out.println("regular instances: " + numToCreate);
          System.out.println("spot instances: " + spotToCreate);
          // Create regular and spot instances
          if (numToCreate > 0) {
            papa.createInstances(ec2Client, numToCreate, imageID);
          }
          if (spotToCreate > 0) {
            papa.createSpotInstances(ec2Client, spotToCreate, Constants.imageID); // FIXME
          }
          System.out.println("created instances");
        } catch (Exception e) {
          // Report ec2 exceptions
          logger.error(e);
          e.printStackTrace();
          continue;
        }
      }
      try {
        Thread.sleep(60000); // we wait for any new servers to start up
      } catch (InterruptedException e) {
        logger.error("Sqslistener was interrupted");
        if (papa.getShuttingDown()) {
          break;
        } else {
          continue;
        }
      }
    }
  }