使用RunInstancesRequest获取AWS EC2实例详细信息

Question

我试图使用RunInstancesRequest获取AWS EC2实例的详细信息。为此，我遵循了AWS文档https://docs.AWS.amazon.com/sdk-for-java/v1/developer-guide/examples-ec2-instances.html。

RunInstancesRequest runInstancesRequest = new RunInstancesRequest();
runInstancesRequest.withImageId(imageId).withInstanceType(instanceType).withMinCount(1).withMaxCount(count).withSecurityGroups(securityGroupName);
RunInstancesResult runInstancesResult = amazonEC2.runInstances(runInstancesRequest);
String instance_id = runInstancesResult.getReservation().getReservationId();
//waiting for 2 minute
DescribeInstancesRequest describeInstancesRequest = new DescribeInstancesRequest();
describeInstancesRequest.setInstanceIds(Arrays.asList(instance_id));
DescribeInstancesResult describeInstancesResult = amazonEC2.describeInstances(describeInstancesRequest);
for(Reservation reservation : describeInstancesResult.getReservations()){
    for(Instance instance : reservation.getInstances()) {
         System.out.println(instance.getPublicDnsName());
    }
}

在这里，我能够启动并运行AWS EC2实例，但我面临的问题是，我无法使用RunInstancesResult对象获取EC2详细信息。根据AWS文档，instance_id似乎是reservation_id，但我认为并非如此。因为instance_id以“i-”开头，而reservation_id以“r-”开头。

我如何才能得到我使用API创建的仅一个EC2的细节？当我获得runinstancesresult对象作为上一个API的输出时，问题就来了：如何使用runinstancesRequest获得AWS EC2实例的详细信息？

Answer 1

保留是启动实例的请求。例如，可以使用一个启动请求创建两个实例。因此，保留包含多个实例。

如果查看response对象，您将看到保留确实包含多个实例，例如：

{
    "OwnerId": "123456789012",
    "ReservationId": "r-08626e73c547023b1",
    "Groups": [
        {
            "GroupName": "MySecurityGroup",
            "GroupId": "sg-903004f8"
        }
    ],
    "Instances": [
        {
            "Monitoring": {
                "State": "disabled"
            },
            "PublicDnsName": null,
            "RootDeviceType": "ebs",
            "State": {
                "Code": 0,
                "Name": "pending"
            },
            "EbsOptimized": false,
            "LaunchTime": "2013-07-19T02:42:39.000Z",
            "ProductCodes": [],
            "StateTransitionReason": null,
            "InstanceId": "i-1234567890abcdef0",
            "ImageId": "ami-1a2b3c4d",
            "PrivateDnsName": null,
            "KeyName": "MyKeyPair",
etc.