Use CreateLaunchTemplate with an AWS SDK or CLI

    /// <summary>
    /// Creates an Amazon EC2 launch template to use with Amazon EC2 Auto Scaling.
    /// The launch template specifies a Bash script in its user data field that runs after
    /// the instance is started. This script installs the Python packages and starts a Python
    /// web server on the instance.
    /// </summary>
    /// <param name="startupScriptPath">The path to a Bash script file that is run.</param>
    /// <param name="instancePolicyPath">The path to a permissions policy to create and attach to the profile.</param>
    /// <returns>The template object.</returns>
    public async Task<Amazon.EC2.Model.LaunchTemplate> CreateTemplate(string startupScriptPath, string instancePolicyPath)
    {
        try
        {
            await CreateKeyPair(_keyPairName);
            await CreateInstanceProfileWithName(_instancePolicyName, _instanceRoleName,
                _instanceProfileName, instancePolicyPath);

            var startServerText = await File.ReadAllTextAsync(startupScriptPath);
            var plainTextBytes = System.Text.Encoding.UTF8.GetBytes(startServerText);

            var amiLatest = await _amazonSsm.GetParameterAsync(
                new GetParameterRequest() { Name = _amiParam });
            var amiId = amiLatest.Parameter.Value;
            var launchTemplateResponse = await _amazonEc2.CreateLaunchTemplateAsync(
                new CreateLaunchTemplateRequest()
                {
                    LaunchTemplateName = _launchTemplateName,
                    LaunchTemplateData = new RequestLaunchTemplateData()
                    {
                        InstanceType = _instanceType,
                        ImageId = amiId,
                        IamInstanceProfile =
                            new
                                LaunchTemplateIamInstanceProfileSpecificationRequest()
                            {
                                Name = _instanceProfileName
                            },
                        KeyName = _keyPairName,
                        UserData = System.Convert.ToBase64String(plainTextBytes)
                    }
                });
            return launchTemplateResponse.LaunchTemplate;
        }
        catch (AmazonEC2Exception ec2Exception)
        {
            if (ec2Exception.ErrorCode == "InvalidLaunchTemplateName.AlreadyExistsException")
            {
                _logger.LogError($"Could not create the template, the name {_launchTemplateName} already exists. " +
                                 $"Please try again with a unique name.");
            }

            throw;
        }
        catch (Exception ex)
        {
            _logger.LogError($"An error occurred while creating the template.: {ex.Message}");
            throw;
        }
    }

Example 1: To create a launch template

The following create-launch-template example creates a launch template that specifies the subnet in which to launch the instance , assigns a public IP address and an IPv6 address to the instance, and creates a tag for the instance.

aws ec2 create-launch-template \
    --launch-template-name TemplateForWebServer \
    --version-description WebVersion1 \
    --launch-template-data '{"NetworkInterfaces":[{"AssociatePublicIpAddress":true,"DeviceIndex":0,"Ipv6AddressCount":1,"SubnetId":"subnet-7b16de0c"}],"ImageId":"ami-8c1be5f6","InstanceType":"t2.small","TagSpecifications":[{"ResourceType":"instance","Tags":[{"Key":"purpose","Value":"webserver"}]}]}'

Output:

{
    "LaunchTemplate": {
        "LatestVersionNumber": 1,
        "LaunchTemplateId": "lt-01238c059e3466abc",
        "LaunchTemplateName": "TemplateForWebServer",
        "DefaultVersionNumber": 1,
        "CreatedBy": "arn:aws:iam::123456789012:user/Bob",
        "CreateTime": "2019-01-27T09:13:24.000Z"
    }
}

For more information, see Launching an Instance from a Launch Template in the Amazon Elastic Compute Cloud User Guide. For information about quoting JSON-formatted parameters, see Quoting Strings in the AWS Command Line Interface User Guide.

Example 2: To create a launch template for Amazon EC2 Auto Scaling

The following create-launch-template example creates a launch template with multiple tags and a block device mapping to specify an additional EBS volume when an instance launches. Specify a value for Groups that corresponds to security groups for the VPC that your Auto Scaling group will launch instances into. Specify the VPC and subnets as properties of the Auto Scaling group.

aws ec2 create-launch-template \
    --launch-template-name TemplateForAutoScaling \
    --version-description AutoScalingVersion1 \
    --launch-template-data '{"NetworkInterfaces":[{"DeviceIndex":0,"AssociatePublicIpAddress":true,"Groups":["sg-7c227019,sg-903004f8"],"DeleteOnTermination":true}],"ImageId":"ami-b42209de","InstanceType":"m4.large","TagSpecifications":[{"ResourceType":"instance","Tags":[{"Key":"environment","Value":"production"},{"Key":"purpose","Value":"webserver"}]},{"ResourceType":"volume","Tags":[{"Key":"environment","Value":"production"},{"Key":"cost-center","Value":"cc123"}]}],"BlockDeviceMappings":[{"DeviceName":"/dev/sda1","Ebs":{"VolumeSize":100}}]}' --region us-east-1

Output:

{
    "LaunchTemplate": {
        "LatestVersionNumber": 1,
        "LaunchTemplateId": "lt-0123c79c33a54e0abc",
        "LaunchTemplateName": "TemplateForAutoScaling",
        "DefaultVersionNumber": 1,
        "CreatedBy": "arn:aws:iam::123456789012:user/Bob",
        "CreateTime": "2019-04-30T18:16:06.000Z"
    }
}

For more information, see Creating a Launch Template for an Auto Scaling Group in the Amazon EC2 Auto Scaling User Guide. For information about quoting JSON-formatted parameters, see Quoting Strings in the AWS Command Line Interface User Guide.

Example 3: To create a launch template that specifies encryption of EBS volumes

The following create-launch-template example creates a launch template that includes encrypted EBS volumes created from an unencrypted snapshot. It also tags the volumes during creation. If encryption by default is disabled, you must specify the "Encrypted" option as shown in the following example. If you use the "KmsKeyId" option to specify a customer managed CMK, you also must specify the "Encrypted" option even if encryption by default is enabled.

aws ec2 create-launch-template \
  --launch-template-name TemplateForEncryption \
  --launch-template-data file://config.json

Contents of config.json:

{
    "BlockDeviceMappings":[
        {
            "DeviceName":"/dev/sda1",
            "Ebs":{
                "VolumeType":"gp2",
                "DeleteOnTermination":true,
                "SnapshotId":"snap-066877671789bd71b",
                "Encrypted":true,
                "KmsKeyId":"arn:aws:kms:us-east-1:012345678910:key/abcd1234-a123-456a-a12b-a123b4cd56ef"
            }
        }
    ],
    "ImageId":"ami-00068cd7555f543d5",
    "InstanceType":"c5.large",
    "TagSpecifications":[
        {
            "ResourceType":"volume",
            "Tags":[
                {
                    "Key":"encrypted",
                    "Value":"yes"
                }
            ]
        }
    ]
}

Output:

{
    "LaunchTemplate": {
        "LatestVersionNumber": 1,
        "LaunchTemplateId": "lt-0d5bd51bcf8530abc",
        "LaunchTemplateName": "TemplateForEncryption",
        "DefaultVersionNumber": 1,
        "CreatedBy": "arn:aws:iam::123456789012:user/Bob",
        "CreateTime": "2020-01-07T19:08:36.000Z"
    }
}

For more information, see Restoring an Amazon EBS Volume from a Snapshot and Encryption by Default in the Amazon Elastic Compute Cloud User Guide.

    const ssmClient = new SSMClient({});
    const { Parameter } = await ssmClient.send(
      new GetParameterCommand({
        Name: "/aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2",
      }),
    );
    const ec2Client = new EC2Client({});
    await ec2Client.send(
      new CreateLaunchTemplateCommand({
        LaunchTemplateName: NAMES.launchTemplateName,
        LaunchTemplateData: {
          InstanceType: "t3.micro",
          ImageId: Parameter.Value,
          IamInstanceProfile: { Name: NAMES.instanceProfileName },
          UserData: readFileSync(
            join(RESOURCES_PATH, "server_startup_script.sh"),
          ).toString("base64"),
          KeyName: NAMES.keyPairName,
        },
      }),

This example creates a launch template that includes an instance profile that grants specific permissions to the instance, and a user data Bash script that runs on the instance after it starts.

class AutoScalingWrapper:
    """
    Encapsulates Amazon EC2 Auto Scaling and EC2 management actions.
    """

    def __init__(
        self,
        resource_prefix: str,
        inst_type: str,
        ami_param: str,
        autoscaling_client: boto3.client,
        ec2_client: boto3.client,
        ssm_client: boto3.client,
        iam_client: boto3.client,
    ):
        """
        Initializes the AutoScaler class with the necessary parameters.

        :param resource_prefix: The prefix for naming AWS resources that are created by this class.
        :param inst_type: The type of EC2 instance to create, such as t3.micro.
        :param ami_param: The Systems Manager parameter used to look up the AMI that is created.
        :param autoscaling_client: A Boto3 EC2 Auto Scaling client.
        :param ec2_client: A Boto3 EC2 client.
        :param ssm_client: A Boto3 Systems Manager client.
        :param iam_client: A Boto3 IAM client.
        """
        self.inst_type = inst_type
        self.ami_param = ami_param
        self.autoscaling_client = autoscaling_client
        self.ec2_client = ec2_client
        self.ssm_client = ssm_client
        self.iam_client = iam_client
        sts_client = boto3.client("sts")
        self.account_id = sts_client.get_caller_identity()["Account"]

        self.key_pair_name = f"{resource_prefix}-key-pair"
        self.launch_template_name = f"{resource_prefix}-template-"
        self.group_name = f"{resource_prefix}-group"

        # Happy path
        self.instance_policy_name = f"{resource_prefix}-pol"
        self.instance_role_name = f"{resource_prefix}-role"
        self.instance_profile_name = f"{resource_prefix}-prof"

        # Failure mode
        self.bad_creds_policy_name = f"{resource_prefix}-bc-pol"
        self.bad_creds_role_name = f"{resource_prefix}-bc-role"
        self.bad_creds_profile_name = f"{resource_prefix}-bc-prof"


    def create_template(
        self, server_startup_script_file: str, instance_policy_file: str
    ) -> Dict[str, Any]:
        """
        Creates an Amazon EC2 launch template to use with Amazon EC2 Auto Scaling. The
        launch template specifies a Bash script in its user data field that runs after
        the instance is started. This script installs Python packages and starts a
        Python web server on the instance.

        :param server_startup_script_file: The path to a Bash script file that is run
                                           when an instance starts.
        :param instance_policy_file: The path to a file that defines a permissions policy
                                     to create and attach to the instance profile.
        :return: Information about the newly created template.
        """
        template = {}
        try:
            # Create key pair and instance profile
            self.create_key_pair(self.key_pair_name)
            self.create_instance_profile(
                instance_policy_file,
                self.instance_policy_name,
                self.instance_role_name,
                self.instance_profile_name,
            )

            # Read the startup script
            with open(server_startup_script_file) as file:
                start_server_script = file.read()

            # Get the latest AMI ID
            ami_latest = self.ssm_client.get_parameter(Name=self.ami_param)
            ami_id = ami_latest["Parameter"]["Value"]

            # Create the launch template
            lt_response = self.ec2_client.create_launch_template(
                LaunchTemplateName=self.launch_template_name,
                LaunchTemplateData={
                    "InstanceType": self.inst_type,
                    "ImageId": ami_id,
                    "IamInstanceProfile": {"Name": self.instance_profile_name},
                    "UserData": base64.b64encode(
                        start_server_script.encode(encoding="utf-8")
                    ).decode(encoding="utf-8"),
                    "KeyName": self.key_pair_name,
                },
            )
            template = lt_response["LaunchTemplate"]
            log.info(
                f"Created launch template {self.launch_template_name} for AMI {ami_id} on {self.inst_type}."
            )
        except ClientError as err:
            log.error(f"Failed to create launch template {self.launch_template_name}.")
            error_code = err.response["Error"]["Code"]
            if error_code == "InvalidLaunchTemplateName.AlreadyExistsException":
                log.info(
                    f"Launch template {self.launch_template_name} already exists, nothing to do."
                )
            log.error(f"Full error:\n\t{err}")
        return template