在你提到用户作为根用户的问题中，我应该提到的一件事是实例ID不依赖于用户。

对于Node开发者来说，

var meta  = new AWS.MetadataService();

meta.request("/latest/meta-data/instance-id", function(err, data){
    console.log(data);
});

对于c++(使用cURL):

    #include <curl/curl.h>

    //// cURL to string
    size_t curl_to_str(void *contents, size_t size, size_t nmemb, void *userp) {
        ((std::string*)userp)->append((char*)contents, size * nmemb);
        return size * nmemb;
    };

    //// Read Instance-id 
    curl_global_init(CURL_GLOBAL_ALL); // Initialize cURL
    CURL *curl; // cURL handler
    CURLcode res_code; // Result
    string response;
    curl = curl_easy_init(); // Initialize handler
    curl_easy_setopt(curl, CURLOPT_URL, "http://169.254.169.254/latest/meta-data/instance-id");
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, curl_to_str);
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response);
    res_code = curl_easy_perform(curl); // Perform cURL
    if (res_code != CURLE_OK) { }; // Error
    curl_easy_cleanup(curl); // Cleanup handler
    curl_global_cleanup(); // Cleanup cURL

我从http api为EC2元数据编写的c# .net类。 我将根据需要构建它的功能。如果你喜欢，你可以用它。

using Amazon;
using System.Net;

namespace AT.AWS
{
    public static class HttpMetaDataAPI
    {
        public static bool TryGetPublicIP(out string publicIP)
        {
            return TryGetMetaData("public-ipv4", out publicIP);
        }
        public static bool TryGetPrivateIP(out string privateIP)
        {
            return TryGetMetaData("local-ipv4", out privateIP);
        }
        public static bool TryGetAvailabilityZone(out string availabilityZone)
        {
            return TryGetMetaData("placement/availability-zone", out availabilityZone);
        }

        /// <summary>
        /// Gets the url of a given AWS service, according to the name of the required service and the AWS Region that this machine is in
        /// </summary>
        /// <param name="serviceName">The service we are seeking (such as ec2, rds etc)</param>
        /// <remarks>Each AWS service has a different endpoint url for each region</remarks>
        /// <returns>True if the operation was succesful, otherwise false</returns>
        public static bool TryGetServiceEndpointUrl(string serviceName, out string serviceEndpointStringUrl)
        {
            // start by figuring out what region this instance is in.
            RegionEndpoint endpoint;
            if (TryGetRegionEndpoint(out endpoint))
            {
                // now that we know the region, we can get details about the requested service in that region
                var details = endpoint.GetEndpointForService(serviceName);
                serviceEndpointStringUrl = (details.HTTPS ? "https://" : "http://") + details.Hostname;
                return true;
            }
            // satisfy the compiler by assigning a value to serviceEndpointStringUrl
            serviceEndpointStringUrl = null;
            return false;
        }
        public static bool TryGetRegionEndpoint(out RegionEndpoint endpoint)
        {
            // we can get figure out the region end point from the availability zone
            // that this instance is in, so we start by getting the availability zone:
            string availabilityZone;
            if (TryGetAvailabilityZone(out availabilityZone))
            {
                // name of the availability zone is <nameOfRegionEndpoint>[a|b|c etc]
                // so just take the name of the availability zone and chop off the last letter
                var nameOfRegionEndpoint = availabilityZone.Substring(0, availabilityZone.Length - 1);
                endpoint = RegionEndpoint.GetBySystemName(nameOfRegionEndpoint);
                return true;
            }
            // satisfy the compiler by assigning a value to endpoint
            endpoint = RegionEndpoint.USWest2;
            return false;
        }
        /// <summary>
        /// Downloads instance metadata
        /// </summary>
        /// <returns>True if the operation was successful, false otherwise</returns>
        /// <remarks>The operation will be unsuccessful if the machine running this code is not an AWS EC2 machine.</remarks>
        static bool TryGetMetaData(string name, out string result)
        {
            result = null;
            try { result = new WebClient().DownloadString("http://169.254.169.254/latest/meta-data/" + name); return true; }
            catch { return false; }
        }

/************************************************************
 * MetaData keys.
 *   Use these keys to write more functions as you need them
 * **********************************************************
ami-id
ami-launch-index
ami-manifest-path
block-device-mapping/
hostname
instance-action
instance-id
instance-type
local-hostname
local-ipv4
mac
metrics/
network/
placement/
profile
public-hostname
public-ipv4
public-keys/
reservation-id
security-groups
*************************************************************/
    }
}

动机:用户想检索aws实例元数据。

解决方案: IP地址169.254.169.254是一个链接本地地址(仅对实例有效)aws为我们提供了用于检索运行实例的元数据的专用Restful API的链接(注意，用于检索实例元数据和用户数据的HTTP请求不会收费)。其他文件

例子:

//Request:
curl http://169.254.169.254/latest/meta-data/instance-id

//Response
ami-123abc

你可以使用这个链接http://169.254.169.254/latest/meta-data/<metadata-field>获得你实例的额外元数据标签，只需选择正确的标签:

ami id ami-launch-index ami-manifest-path 块设备 映射 事件 冬眠 主机名 我 身份凭证 instance-action 实例id 实例类型 local-hostname local-ipv4 mac 指标 网络 放置 配置文件 预订标识 安全组 服务

在Ubuntu上你可以:

sudo apt-get install cloud-utils

然后你就可以:

EC2_INSTANCE_ID=$(ec2metadata --instance-id)

你可以通过这种方式获取大多数与实例相关的元数据:

ec2metadata --help
Syntax: /usr/bin/ec2metadata [options]

Query and display EC2 metadata.

If no options are provided, all options will be displayed

Options:
    -h --help               show this help

    --kernel-id             display the kernel id
    --ramdisk-id            display the ramdisk id
    --reservation-id        display the reservation id

    --ami-id                display the ami id
    --ami-launch-index      display the ami launch index
    --ami-manifest-path     display the ami manifest path
    --ancestor-ami-ids      display the ami ancestor id
    --product-codes         display the ami associated product codes
    --availability-zone     display the ami placement zone

    --instance-id           display the instance id
    --instance-type         display the instance type

    --local-hostname        display the local hostname
    --public-hostname       display the public hostname

    --local-ipv4            display the local ipv4 ip address
    --public-ipv4           display the public ipv4 ip address

    --block-device-mapping  display the block device id
    --security-groups       display the security groups

    --mac                   display the instance mac address
    --profile               display the instance profile
    --instance-action       display the instance-action

    --public-keys           display the openssh public keys
    --user-data             display the user data (not actually metadata)

对于AWS elastic beanstalk eb cli，请执行eb tags——list