Question

我想在新用户到达时创建ec2实例。我创建了一个servlet类来执行此操作。当用户到达时，如果是新用户，则检查用户是否为新用户，然后创建实例并发送回他/她的IP。当我一个接一个地向用户发送http请求给我的用户时，我正确地获得了IP。但是当我并行发送HTTP呼叫时（对于user1发送请求在tab1中，对于user2发送请求同时在tab2中获取来自user1 HTTP呼叫的响应）。当我这样做时，我得到了错误。有时user1说

＆＃34;实例ID＆＃39; i-0b79495934c3b5459＆＃39;不存在（服务： AmazonEC2;状态代码：400;错误代码：InvalidInstanceID.NotFound; 要求ID：e18a9eaa-cb1b-4130-a3ee-bf1b19fa184c）＆＃34;

user2发送IP作为响应。请帮助我什么问题以及如何解决这个问题。这是我创建的Servlet类。

public class GateKeeperController extends HttpServlet {
    private static final long serialVersionUID = 1L;
    BasicAWSCredentials awsCreds = new BasicAWSCredentials(credentials);
    AmazonEC2Client ec2Client = new AmazonEC2Client(awsCreds);
    RunInstancesRequest runInstancesRequest;
    RunInstancesResult runInstancesResult;
    Reservation reservation;
    Instance intstance;
    DescribeInstancesRequest describeInstanceRequest;
    DescribeInstancesResult describeInstanceResult;
    GatekeeperModal gateKeepermodal;
    String sourceAMI = null;
    String destinationAMI = null;

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        HttpSession s = request.getSession();
        String userID = (String) request.getParameter("userID");
        Double lattitude = Double.parseDouble((String) request.getParameter("lat"));
        Double lonitude = Double.parseDouble((String) request.getParameter("long"));
        if (userID != null) {
            Pair coordinates = new Pair(lattitude, lonitude);
            RegionSelection targetRegion = new RegionSelection();
            String regionResult = targetRegion.getRegion(coordinates);
            String instanceIP = null;
            gateKeepermodal = new GatekeeperModal();
            try {
                if (gateKeepermodal.checkUserIsNew(userID)) {
                    instanceIP = startInstance(userID, regionResult);
                    if (instanceIP != null) {
                        response.getWriter().write(instanceIP);
                    }
                } 
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        } else {

        }
    }

    private String startInstance(String userID, String region) {
        String ami_id = new AMI().getAMI_ID(region);

        ec2Client.setEndpoint(region);
        runInstancesRequest = new RunInstancesRequest();
        runInstancesRequest.withImageId(ami_id).withInstanceType("t2.micro").withMinCount(1).withMaxCount(1)
                .withKeyName("GateKeeper_User").withSecurityGroups("GateKeeper User");
        runInstancesResult = ec2Client.runInstances(runInstancesRequest);
        reservation = runInstancesResult.getReservation();
        intstance = reservation.getInstances().get(0);
        String s1 = intstance.getState().getName();
        String s2 = InstanceStateName.Running.name();
        while (!s1.toLowerCase().equals(s2.toLowerCase())) {
            describeInstanceRequest = new DescribeInstancesRequest();
            describeInstanceRequest.withInstanceIds(intstance.getInstanceId());
            ec2Client.setEndpoint(region);
            describeInstanceResult = ec2Client.describeInstances(describeInstanceRequest);
            reservation = describeInstanceResult.getReservations().get(0);
            intstance = reservation.getInstances().get(0);
            s1 = intstance.getState().getName();
            s2 = InstanceStateName.Running.name();
        }
        GateKeeperUser user = new GateKeeperUser(userID, intstance.getInstanceId(), intstance.getPublicIpAddress(),
                region);
        Boolean result;
        try {
            result = gateKeepermodal.createUser(user);
            if (result) {
                return intstance.getPublicIpAddress();
            } else {
                return null;
            }

        } catch (SQLException e) {

        }
        return null;
    }
}

Answer 1

根据documentation：

＆＃34;如果您成功运行RunInstances命令，然后使用实例ID立即运行另一个命令在RunInstances的响应中提供，它可能返回一个 InvalidInstanceID.NotFound错误。这并不意味着实例会这样做不存在。可能受影响的一些特定命令是： DescribeInstances：要确认实例的实际状态，请运行此命令使用指数退避算法。 TerminateInstances：要确认实例的状态，请先运行 DescribeInstances命令使用指数退避算法。＆＃34;

AWS EC2实例：启动多个实例

1 个答案: