Gather what you need Launch an instance Monitor the instance Complete code Additional considerations (optional) Connect to the instance Clean up

Launching an Amazon EC2 instance

This example shows you how to use the AWS SDK for .NET to launch one or more identically configured Amazon EC2 instances from the same Amazon Machine Image (AMI). Using several inputs that you supply, the application launches an EC2 instance and then monitors the instance until it's out of the "Pending" state.

When your EC2 instance is running, you can connect to it remotely, as described in (optional) Connect to the instance.

You can launch an EC2 instance in a VPC or in EC2-Classic (if your AWS account supports this). For more information about EC2 in a VPC versus EC2-Classic, see the Amazon EC2 User Guide for Linux Instances or the Amazon EC2 User Guide for Windows Instances.

Warning

We are retiring EC2-Classic on August 15, 2022. We recommend that you migrate from EC2-Classic to a VPC. For more information, see Migrate from EC2-Classic to a VPC in the Amazon EC2 User Guide for Linux Instances or the Amazon EC2 User Guide for Windows Instances. Also see the blog post EC2-Classic Networking is Retiring – Here's How to Prepare.

The following sections provide snippets and other information for this example. The complete code for the example is shown after the snippets, and can be built and run as is.

Gather what you need

To launch an EC2 instance, you'll need several things.

A VPC where the instance will be launched. If it'll be a Windows instance and you'll be connecting to it through RDP, the VPC will most likely need to have an internet gateway attached to it, as well as an entry for the internet gateway in the route table. For more information, see Internet gateways in the Amazon VPC User Guide.

The ID of an existing subnet in the VPC where the instance will be launched. An easy way to find or create this is to sign in to the Amazon VPC console, but you can also obtain it programmatically by using the CreateSubnetAsync and DescribeSubnetsAsync methods.

Note
If your AWS account supports EC2-Classic and that's the type of instance you want to launch, this parameter isn't required. However, if your account doesn't support EC2-Classic and you don't supply this parameter, the new instance is launched in the default VPC for your account.

The ID of an existing security group that belongs to the VPC where the instance will be launched. For more information, see Working with security groups in Amazon EC2.

If you want to connect to the new instance, the security group mentioned earlier must have an appropriate inbound rule that allows SSH traffic on port 22 (Linux instance) or RDP traffic on port 3389 (Windows instance). For information about how to do this see Updating security groups, including the Additional considerations near the end of that topic.

The Amazon Machine Image (AMI) that will be used to create the instance. See the information about AMIs in the Amazon EC2 User Guide for Linux Instances or the Amazon EC2 User Guide for Windows Instances. For example, read about shared AMIs in the Amazon EC2 User Guide for Linux Instances or the Amazon EC2 User Guide for Windows Instances.

The name of an existing EC2 key pair, which is used to connect to the new instance. For more information, see Working with Amazon EC2 key pairs.

The name of the PEM file that contains the private key of the EC2 key pair mentioned earlier. The PEM file is used when you connect remotely to the instance.

Launch an instance

The following snippet launches an EC2 instance.

The example near the end of this topic shows this snippet in use.


    //
    // Method to launch the instances
    // Returns a list with the launched instance IDs
    private static async Task<List<string>> LaunchInstances(
      IAmazonEC2 ec2Client, RunInstancesRequest requestLaunch)
    {
      var instanceIds = new List<string>();
      RunInstancesResponse responseLaunch =
        await ec2Client.RunInstancesAsync(requestLaunch);

      Console.WriteLine("\nNew instances have been created.");
      foreach (Instance item in responseLaunch.Reservation.Instances)
      {
        instanceIds.Add(item.InstanceId);
        Console.WriteLine($"  New instance: {item.InstanceId}");
      }

      return instanceIds;
    }

Monitor the instance

The following snippet monitors the instance until it's out of the "Pending" state.

The example near the end of this topic shows this snippet in use.

See the InstanceState class for the valid values of the Instance.State.Code property.


    //
    // Method to wait until the instances are running (or at least not pending)
    private static async Task CheckState(IAmazonEC2 ec2Client, List<string> instanceIds)
    {
      Console.WriteLine(
        "\nWaiting for the instances to start." +
        "\nPress any key to stop waiting. (Response might be slightly delayed.)");

      int numberRunning;
      DescribeInstancesResponse responseDescribe;
      var requestDescribe = new DescribeInstancesRequest{
        InstanceIds = instanceIds};

      // Check every couple of seconds
      int wait = 2000;
      while(true)
      {
        // Get and check the status for each of the instances to see if it's past pending.
        // Once all instances are past pending, break out.
        // (For this example, we are assuming that there is only one reservation.)
        Console.Write(".");
        numberRunning = 0;
        responseDescribe = await ec2Client.DescribeInstancesAsync(requestDescribe);
        foreach(Instance i in responseDescribe.Reservations[0].Instances)
        {
          // Check the lower byte of State.Code property
          // Code == 0 is the pending state
          if((i.State.Code & 255) > 0) numberRunning++;
        }
        if(numberRunning == responseDescribe.Reservations[0].Instances.Count)
          break;

        // Wait a bit and try again (unless the user wants to stop waiting)
        Thread.Sleep(wait);
        if(Console.KeyAvailable)
          break;
      }

      Console.WriteLine("\nNo more instances are pending.");
      foreach(Instance i in responseDescribe.Reservations[0].Instances)
      {
        Console.WriteLine($"For {i.InstanceId}:");
        Console.WriteLine($"  VPC ID: {i.VpcId}");
        Console.WriteLine($"  Instance state: {i.State.Name}");
        Console.WriteLine($"  Public IP address: {i.PublicIpAddress}");
        Console.WriteLine($"  Public DNS name: {i.PublicDnsName}");
        Console.WriteLine($"  Key pair name: {i.KeyName}");
      }
    }

Complete code

This section shows relevant references and the complete code for this example.

NuGet packages:

AWSSDK.EC2

Programming elements:

Namespace Amazon.EC2

Class AmazonEC2Client

Class InstanceType
Namespace Amazon.EC2.Model

Class DescribeInstancesRequest

Class DescribeInstancesResponse

Class Instance

Class InstanceNetworkInterfaceSpecification

Class RunInstancesRequest

Class RunInstancesResponse


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

namespace EC2LaunchInstance
{
  // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
  // Class to launch an EC2 instance
  class Program
  {
    static async Task Main(string[] args)
    {
      // Parse the command line and show help if necessary
      var parsedArgs = CommandLine.Parse(args);
      if(parsedArgs.Count == 0)
      {
        PrintHelp();
        return;
      }

      // Get the application arguments from the parsed list
      string groupID =
        CommandLine.GetArgument(parsedArgs, null, "-g", "--group-id");
      string ami =
        CommandLine.GetArgument(parsedArgs, null, "-a", "--ami-id");
      string keyPairName =
        CommandLine.GetArgument(parsedArgs, null, "-k", "--keypair-name");
      string subnetID =
        CommandLine.GetArgument(parsedArgs, null, "-s", "--subnet-id");
      if(   (string.IsNullOrEmpty(groupID) || !groupID.StartsWith("sg-"))
         || (string.IsNullOrEmpty(ami) || !ami.StartsWith("ami-"))
         || (string.IsNullOrEmpty(keyPairName))
         || (!string.IsNullOrEmpty(subnetID) && !subnetID.StartsWith("subnet-")))
        CommandLine.ErrorExit(
          "\nOne or more of the required arguments is missing or incorrect." +
          "\nRun the command with no arguments to see help.");

      // Create an EC2 client
      var ec2Client = new AmazonEC2Client();

      // Create an object with the necessary properties
      RunInstancesRequest request = GetRequestData(groupID, ami, keyPairName, subnetID);

      // Launch the instances and wait for them to start running
      var instanceIds = await LaunchInstances(ec2Client, request);
      await CheckState(ec2Client, instanceIds);
    }


    //
    // Method to put together the properties needed to launch the instance.
    private static RunInstancesRequest GetRequestData(
      string groupID, string ami, string keyPairName, string subnetID)
    {
      // Common properties
      var groupIDs = new List<string>() { groupID };
      var request = new RunInstancesRequest()
      {
        // The first three of these would be additional command-line arguments or similar.
        InstanceType = InstanceType.T1Micro,
        MinCount = 1,
        MaxCount = 1,
        ImageId = ami,
        KeyName = keyPairName
      };

      // Properties specifically for EC2 in a VPC.
      if(!string.IsNullOrEmpty(subnetID))
      {
        request.NetworkInterfaces =
          new List<InstanceNetworkInterfaceSpecification>() {
            new InstanceNetworkInterfaceSpecification() {
              DeviceIndex = 0,
              SubnetId = subnetID,
              Groups = groupIDs,
              AssociatePublicIpAddress = true
            }
          };
      }

      // Properties specifically for EC2-Classic
      else
      {
        request.SecurityGroupIds = groupIDs;
      }
      return request;
    }


    //
    // Method to launch the instances
    // Returns a list with the launched instance IDs
    private static async Task<List<string>> LaunchInstances(
      IAmazonEC2 ec2Client, RunInstancesRequest requestLaunch)
    {
      var instanceIds = new List<string>();
      RunInstancesResponse responseLaunch =
        await ec2Client.RunInstancesAsync(requestLaunch);

      Console.WriteLine("\nNew instances have been created.");
      foreach (Instance item in responseLaunch.Reservation.Instances)
      {
        instanceIds.Add(item.InstanceId);
        Console.WriteLine($"  New instance: {item.InstanceId}");
      }

      return instanceIds;
    }


    //
    // Method to wait until the instances are running (or at least not pending)
    private static async Task CheckState(IAmazonEC2 ec2Client, List<string> instanceIds)
    {
      Console.WriteLine(
        "\nWaiting for the instances to start." +
        "\nPress any key to stop waiting. (Response might be slightly delayed.)");

      int numberRunning;
      DescribeInstancesResponse responseDescribe;
      var requestDescribe = new DescribeInstancesRequest{
        InstanceIds = instanceIds};

      // Check every couple of seconds
      int wait = 2000;
      while(true)
      {
        // Get and check the status for each of the instances to see if it's past pending.
        // Once all instances are past pending, break out.
        // (For this example, we are assuming that there is only one reservation.)
        Console.Write(".");
        numberRunning = 0;
        responseDescribe = await ec2Client.DescribeInstancesAsync(requestDescribe);
        foreach(Instance i in responseDescribe.Reservations[0].Instances)
        {
          // Check the lower byte of State.Code property
          // Code == 0 is the pending state
          if((i.State.Code & 255) > 0) numberRunning++;
        }
        if(numberRunning == responseDescribe.Reservations[0].Instances.Count)
          break;

        // Wait a bit and try again (unless the user wants to stop waiting)
        Thread.Sleep(wait);
        if(Console.KeyAvailable)
          break;
      }

      Console.WriteLine("\nNo more instances are pending.");
      foreach(Instance i in responseDescribe.Reservations[0].Instances)
      {
        Console.WriteLine($"For {i.InstanceId}:");
        Console.WriteLine($"  VPC ID: {i.VpcId}");
        Console.WriteLine($"  Instance state: {i.State.Name}");
        Console.WriteLine($"  Public IP address: {i.PublicIpAddress}");
        Console.WriteLine($"  Public DNS name: {i.PublicDnsName}");
        Console.WriteLine($"  Key pair name: {i.KeyName}");
      }
    }


    //
    // Command-line help
    private static void PrintHelp()
    {
      Console.WriteLine(
        "\nUsage: EC2LaunchInstance -g <group-id> -a <ami-id> -k <keypair-name> [-s <subnet-id>]" +
        "\n  -g, --group-id: The ID of the security group." +
        "\n  -a, --ami-id: The ID of an Amazon Machine Image." +
        "\n  -k, --keypair-name - The name of a key pair." +
        "\n  -s, --subnet-id: The ID of a subnet. Required only for EC2 in a VPC.");
    }
  }


  // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
  // Class that represents a command line on the console or terminal.
  // (This is the same for all examples. When you have seen it once, you can ignore it.)
  static class CommandLine
  {
    //
    // Method to parse a command line of the form: "--key value" or "-k value".
    //
    // Parameters:
    // - args: The command-line arguments passed into the application by the system.
    //
    // Returns:
    // A Dictionary with string Keys and Values.
    //
    // If a key is found without a matching value, Dictionary.Value is set to the key
    //  (including the dashes).
    // If a value is found without a matching key, Dictionary.Key is set to "--NoKeyN",
    //  where "N" represents sequential numbers.
    public static Dictionary<string,string> Parse(string[] args)
    {
      var parsedArgs = new Dictionary<string,string>();
      int i = 0, n = 0;
      while(i < args.Length)
      {
        // If the first argument in this iteration starts with a dash it's an option.
        if(args[i].StartsWith("-"))
        {
          var key = args[i++];
          var value = key;

          // Check to see if there's a value that goes with this option?
          if((i < args.Length) && (!args[i].StartsWith("-"))) value = args[i++];
          parsedArgs.Add(key, value);
        }

        // If the first argument in this iteration doesn't start with a dash, it's a value
        else
        {
          parsedArgs.Add("--NoKey" + n.ToString(), args[i++]);
          n++;
        }
      }

      return parsedArgs;
    }

    //
    // Method to get an argument from the parsed command-line arguments
    //
    // Parameters:
    // - parsedArgs: The Dictionary object returned from the Parse() method (shown above).
    // - defaultValue: The default string to return if the specified key isn't in parsedArgs.
    // - keys: An array of keys to look for in parsedArgs.
    public static string GetArgument(
      Dictionary<string,string> parsedArgs, string defaultReturn, params string[] keys)
    {
      string retval = null;
      foreach(var key in keys)
        if(parsedArgs.TryGetValue(key, out retval)) break;
      return retval ?? defaultReturn;
    }

    //
    // Method to exit the application with an error.
    public static void ErrorExit(string msg, int code=1)
    {
      Console.WriteLine("\nError");
      Console.WriteLine(msg);
      Environment.Exit(code);
    }
  }

}

Additional considerations

When checking the state of an EC2 instance, you can add a filter to the Filter property of the DescribeInstancesRequest object. Using this technique, you can limit the request to certain instances; for example, instances with a particular user-specified tag.

For brevity, some properties were given typical values. Any or all of these properties can instead be determined programmatically or by user input.

The values you can use for the MinCount and MaxCount properties of the RunInstancesRequest object are determined by the target Availability Zone and the maximum number of instances you’re allowed for the instance type. For more information, see How many instances can I run in Amazon EC2 in the Amazon EC2 General FAQ.

If you want to use a different instance type than this example, there are several instance types to choose from, which you can see in the Amazon EC2 User Guide for Linux Instances or the Amazon EC2 User Guide for Windows Instances.

You can also attach an IAM role to an instance when you launch it. To do so, create an IamInstanceProfileSpecification object whose Name property is set to the name of an IAM role. Then add that object to the IamInstanceProfile property of the RunInstancesRequest object.

Note
To launch an EC2 instance that has an IAM role attached, an IAM user's configuration must include certain permissions. For more information about the required permissions, see the Amazon EC2 User Guide for Linux Instances or the Amazon EC2 User Guide for Windows Instances.

(optional) Connect to the instance

After an instance is running, you can connect to it remotely by using the appropriate remote client. For both Linux and Windows instances, you need the instance's public IP address or public DNS name. You also need the following.

For Linux instances

You can use an SSH client to connect to your Linux instance. Make sure that the security group you used when you launched the instance allows SSH traffic on port 22, as described in Updating security groups.

You also need the private portion of the key pair you used to launch the instance; that is, the PEM file.

For more information, see Connect to your Linux instance in the Amazon EC2 User Guide for Linux Instances.

For Windows instances

You can use an RDP client to connect to your instance. Make sure that the security group you used when you launched the instance allows RDP traffic on port 3389, as described in Updating security groups.

You also need the Administrator password. You can obtain this by using the following example code, which requires the instance ID and the private portion of the key pair used to launch the instance; that is, the PEM file.

For more information, see Connecting to your Windows instance in the Amazon EC2 User Guide for Windows Instances.

Warning

This example code returns the plaintext Administrator password for your instance.

NuGet packages:

AWSSDK.EC2

Programming elements:

Namespace Amazon.EC2

Class AmazonEC2Client
Namespace Amazon.EC2.Model

Class GetPasswordDataRequest

Class GetPasswordDataResponse


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

namespace EC2GetWindowsPassword
{
  // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
  // Class to get the Administrator password of a Windows EC2 instance
  class Program
  {
    static async Task Main(string[] args)
    {
      // Parse the command line and show help if necessary
      var parsedArgs = CommandLine.Parse(args);
      if(parsedArgs.Count == 0)
      {
        PrintHelp();
        return;
      }

      // Get the application arguments from the parsed list
      string instanceID =
        CommandLine.GetArgument(parsedArgs, null, "-i", "--instance-id");
      string pemFileName =
        CommandLine.GetArgument(parsedArgs, null, "-p", "--pem-filename");
      if(   (string.IsNullOrEmpty(instanceID) || !instanceID.StartsWith("i-"))
         || (string.IsNullOrEmpty(pemFileName) || !pemFileName.EndsWith(".pem")))
        CommandLine.ErrorExit(
          "\nOne or more of the required arguments is missing or incorrect." +
          "\nRun the command with no arguments to see help.");

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

      // Get and display the password
      string password = await GetPassword(ec2Client, instanceID, pemFileName);
      Console.WriteLine($"\nPassword: {password}");
    }


    //
    // Method to get the administrator password of a Windows EC2 instance
    private static async Task<string> GetPassword(
      IAmazonEC2 ec2Client, string instanceID, string pemFilename)
    {
      string password = string.Empty;
      GetPasswordDataResponse response =
        await ec2Client.GetPasswordDataAsync(new GetPasswordDataRequest{
          InstanceId = instanceID});
      if(response.PasswordData != null)
      {
        password = response.GetDecryptedPassword(File.ReadAllText(pemFilename));
      }
      else
      {
        Console.WriteLine($"\nThe password is not available for instance {instanceID}.");
        Console.WriteLine($"If this is a Windows instance, the password might not be ready.");
      }
      return password;
    }


    //
    // Command-line help
    private static void PrintHelp()
    {
      Console.WriteLine(
        "\nUsage: EC2GetWindowsPassword -i <instance-id> -p pem-filename" +
        "\n  -i, --instance-id: The name of the EC2 instance." +
        "\n  -p, --pem-filename: The name of the PEM file with the private key.");
    }
  }

  // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
  // Class that represents a command line on the console or terminal.
  // (This is the same for all examples. When you have seen it once, you can ignore it.)
  static class CommandLine
  {
    //
    // Method to parse a command line of the form: "--key value" or "-k value".
    //
    // Parameters:
    // - args: The command-line arguments passed into the application by the system.
    //
    // Returns:
    // A Dictionary with string Keys and Values.
    //
    // If a key is found without a matching value, Dictionary.Value is set to the key
    //  (including the dashes).
    // If a value is found without a matching key, Dictionary.Key is set to "--NoKeyN",
    //  where "N" represents sequential numbers.
    public static Dictionary<string,string> Parse(string[] args)
    {
      var parsedArgs = new Dictionary<string,string>();
      int i = 0, n = 0;
      while(i < args.Length)
      {
        // If the first argument in this iteration starts with a dash it's an option.
        if(args[i].StartsWith("-"))
        {
          var key = args[i++];
          var value = key;

          // Check to see if there's a value that goes with this option?
          if((i < args.Length) && (!args[i].StartsWith("-"))) value = args[i++];
          parsedArgs.Add(key, value);
        }

        // If the first argument in this iteration doesn't start with a dash, it's a value
        else
        {
          parsedArgs.Add("--NoKey" + n.ToString(), args[i++]);
          n++;
        }
      }

      return parsedArgs;
    }

    //
    // Method to get an argument from the parsed command-line arguments
    //
    // Parameters:
    // - parsedArgs: The Dictionary object returned from the Parse() method (shown above).
    // - defaultValue: The default string to return if the specified key isn't in parsedArgs.
    // - keys: An array of keys to look for in parsedArgs.
    public static string GetArgument(
      Dictionary<string,string> parsedArgs, string defaultReturn, params string[] keys)
    {
      string retval = null;
      foreach(var key in keys)
        if(parsedArgs.TryGetValue(key, out retval)) break;
      return retval ?? defaultReturn;
    }

    //
    // Method to exit the application with an error.
    public static void ErrorExit(string msg, int code=1)
    {
      Console.WriteLine("\nError");
      Console.WriteLine(msg);
      Environment.Exit(code);
    }
  }

}

Clean up

When you no longer need your EC2 instance, be sure to terminate it, as described in Terminating an Amazon EC2 instance.

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Document Conventions

EC2 instances

Terminating an EC2 instance

Launching an Amazon EC2 instance

Warning

Topics

Gather what you need

Note

Launch an instance

Monitor the instance

Complete code

Additional considerations

Note

(optional) Connect to the instance

Warning

Clean up