Amazon EC2 Spot 实例教程

您需要进行花费数小时或数天的批处理工作。然而，您可以灵活调整启动和结束时间。您希望看到是否以低于按需实例的成本完成。

您可以使用 Amazon EC2 控制台或 Amazon EC2 API 检查实例类型的 Spot 价格历史记录。在您分析了给定可用区内所需实例类型的价格记录之后，您有两种可供选择的方法发出请求：

您需要进行数据处理工作。您将会非常了解作业结果的价值，从而足以知道它们在计算成本方面的价值。

在分析了实例类型的 Spot 价格记录之后，您选择一个计算时间成本不高于该工作结果成本的价格。由于 Spot 价格的波动，该价格可能会达到或低于您的请求，所以您要创建一个持久请求，并允许它间歇运行。

您对附加容量有一个无法预料的短期需求，该容量不能通过按需实例获得。在您分析了实例类型的 Spot 价格历史记录之后，您选择一个高于历史最高价格的价格，以大幅提高快速执行请求的可能性，并继续计算，直到完成实例。

NuGet 程序包：

编程元素：

using System;
using System.Threading;
using System.Threading.Tasks;
using System.Collections.Generic;
using Amazon.EC2;
using Amazon.EC2.Model;

namespace EC2SpotInstanceRequests
{
  class Program
  {
    static async Task Main(string[] args)
    {
      // Some default values.
      // These could be made into command-line arguments instead.
      var instanceType = InstanceType.T1Micro;
      string securityGroupName = "default";
      string spotPrice = "0.003";
      int instanceCount = 1;

      // Parse the command line arguments
      if((args.Length != 1) || (!args[0].StartsWith("ami-")))
      {
        Console.WriteLine("\nUsage: EC2SpotInstanceRequests ami");
        Console.WriteLine("  ami: the Amazon Machine Image to use for the Spot Instances.");
        return;
      }

      // Create the Amazon EC2 client.
      var ec2Client = new AmazonEC2Client();

      // Create the Spot Instance request and record its ID
      Console.WriteLine("\nCreating spot instance request...");
      var req = await CreateSpotInstanceRequest(
        ec2Client, args[0], securityGroupName, instanceType, spotPrice, instanceCount);
      string requestId = req.SpotInstanceRequestId;

      // Wait for an EC2 Spot Instance to become active
      Console.WriteLine(
        $"Waiting for Spot Instance request with ID {requestId} to become active...");
      int wait = 1;
      var start = DateTime.Now;
      while(true)
      {
        Console.Write(".");

        // Get and check the status to see if the request has been fulfilled.
        var requestInfo = await GetSpotInstanceRequestInfo(ec2Client, requestId);
        if(requestInfo.Status.Code == "fulfilled")
        {
          Console.WriteLine($"\nSpot Instance request {requestId} " +
            $"has been fulfilled by instance {requestInfo.InstanceId}.\n");
          break;
        }

        // Wait a bit and try again, longer each time (1, 2, 4, ...)
        Thread.Sleep(wait);
        wait = wait * 2;
      }

      // Show the user how long it took to fulfill the Spot Instance request.
      TimeSpan span = DateTime.Now.Subtract(start);
      Console.WriteLine($"That took {span.TotalMilliseconds} milliseconds");

      // Perform actions here as needed.
      // For this example, simply wait for the user to hit a key.
      // That gives them a chance to look at the EC2 console to see
      // the running instance if they want to.
      Console.WriteLine("Press any key to start the cleanup...");
      Console.ReadKey(true);

      // Cancel the request.
      // Do this first to make sure that the request can't be re-fulfilled
      // once the Spot Instance has been terminated.
      Console.WriteLine("Canceling Spot Instance request...");
      await CancelSpotInstanceRequest(ec2Client, requestId);

      // Terminate the Spot Instance that's running.
      Console.WriteLine("Terminating the running Spot Instance...");
      await TerminateSpotInstance(ec2Client, requestId);

      Console.WriteLine("Done. Press any key to exit...");
      Console.ReadKey(true);
    }


    //
    // Method to create a Spot Instance request
    private static async Task<SpotInstanceRequest> CreateSpotInstanceRequest(
      IAmazonEC2 ec2Client, string amiId, string securityGroupName,
      InstanceType instanceType, string spotPrice, int instanceCount)
    {
      var launchSpecification = new LaunchSpecification{
        ImageId = amiId,
        InstanceType = instanceType
      };
      launchSpecification.SecurityGroups.Add(securityGroupName);
      var request = new RequestSpotInstancesRequest{
        SpotPrice = spotPrice,
        InstanceCount = instanceCount,
        LaunchSpecification = launchSpecification
      };

      RequestSpotInstancesResponse result =
        await ec2Client.RequestSpotInstancesAsync(request);
      return result.SpotInstanceRequests[0];
    }


    //
    // Method to get information about a Spot Instance request, including the status,
    // instance ID, etc.
    // It gets the information for a specific request (as opposed to all requests).
    private static async Task<SpotInstanceRequest> GetSpotInstanceRequestInfo(
      IAmazonEC2 ec2Client, string requestId)
    {
      var describeRequest = new DescribeSpotInstanceRequestsRequest();
      describeRequest.SpotInstanceRequestIds.Add(requestId);

      DescribeSpotInstanceRequestsResponse describeResponse =
        await ec2Client.DescribeSpotInstanceRequestsAsync(describeRequest);
      return describeResponse.SpotInstanceRequests[0];
    }


    //
    // Method to cancel a Spot Instance request
    private static async Task CancelSpotInstanceRequest(
      IAmazonEC2 ec2Client, string requestId)
    {
      var cancelRequest = new CancelSpotInstanceRequestsRequest();
      cancelRequest.SpotInstanceRequestIds.Add(requestId);

      await ec2Client.CancelSpotInstanceRequestsAsync(cancelRequest);
    }


    //
    // Method to terminate a Spot Instance
    private static async Task TerminateSpotInstance(
      IAmazonEC2 ec2Client, string requestId)
    {
      var describeRequest = new DescribeSpotInstanceRequestsRequest();
      describeRequest.SpotInstanceRequestIds.Add(requestId);

      // Retrieve the Spot Instance request to check for running instances.
      DescribeSpotInstanceRequestsResponse describeResponse =
        await ec2Client.DescribeSpotInstanceRequestsAsync(describeRequest);

      // If there are any running instances, terminate them
      if(   (describeResponse.SpotInstanceRequests[0].Status.Code
              == "request-canceled-and-instance-running")
         || (describeResponse.SpotInstanceRequests[0].State == SpotInstanceState.Active))
      {
        TerminateInstancesResponse response =
          await ec2Client.TerminateInstancesAsync(new TerminateInstancesRequest{
            InstanceIds = new List<string>(){
              describeResponse.SpotInstanceRequests[0].InstanceId } });
        foreach (InstanceStateChange item in response.TerminatingInstances)
        {
          Console.WriteLine($"\n  Terminated instance: {item.InstanceId}");
          Console.WriteLine($"  Instance state: {item.CurrentState.Name}\n");
        }
      }
    }
  }
}