How can I write a script to create EC2 instance

Question

I need to write a script to create EC2 instance up and running. I don't know where to start, can anyone help me with this?

If anyone can give me an example it would be very helpful for me.

Answer 1

You can also use the AWS CDK (Cloud Development Kit) EC2 library:

https://awslabs.github.io/aws-cdk/versions/0.15.2/refs/_aws-cdk_aws-ec2.html

Answer 2

You have two options,

• AWS CLI
• AWS SDK Ruby

You can use the AWS CLI to launch, list, and terminate instances. You'll need a key pair and a security group; for information about creating these through the AWS CLI, see Using Key Pairs and Using Security Groups. You'll also need to select an Amazon Machine Image (AMI) and note its AMI ID. For more information, see Finding a Suitable AMI in the Amazon EC2 User Guide for Linux Instances.

The following command launches a t2.micro instance in the specified subnet:

aws ec2 run-instances --image-id ami-xxxxxxxx --count 1 --instance-type t2.micro --key-name MyKeyPair --security-group-ids sg-xxxxxxxx --subnet-id subnet-xxxxxxxx
{
    "OwnerId": "123456789012",
    "ReservationId": "r-5875ca20",
    "Groups": [
        {
            "GroupName": "my-sg",
            "GroupId": "sg-903004f8"
        }
    ],
    "Instances": [
        {
            "Monitoring": {
                "State": "disabled"
            },
            "PublicDnsName": null,
            "Platform": "windows",
            "State": {
                "Code": 0,
                "Name": "pending"
            },
            "EbsOptimized": false,
            "LaunchTime": "2013-07-19T02:42:39.000Z",
            "PrivateIpAddress": "10.0.1.114",
            "ProductCodes": [],
            "VpcId": "vpc-1a2b3c4d",
            "InstanceId": "i-5203422c",
            "ImageId": "ami-173d747e",
            "PrivateDnsName": ip-10-0-1-114.ec2.internal,
            "KeyName": "MyKeyPair",
            "SecurityGroups": [
                {
                    "GroupName": "my-sg",
                    "GroupId": "sg-903004f8"
                }
            ],
            "ClientToken": null,
            "SubnetId": "subnet-6e7f829e",
            "InstanceType": "t2.micro",
            "NetworkInterfaces": [
                {
                    "Status": "in-use",
                    "SourceDestCheck": true,
                    "VpcId": "vpc-1a2b3c4d",
                    "Description": "Primary network interface",
                    "NetworkInterfaceId": "eni-a7edb1c9",
                    "PrivateIpAddresses": [
                        {
                            "PrivateDnsName": "ip-10-0-1-114.ec2.internal",
                            "Primary": true,
                            "PrivateIpAddress": "10.0.1.114"
                        }
                    ],
                    "PrivateDnsName": "ip-10-0-1-114.ec2.internal",
                    "Attachment": {
                        "Status": "attached",
                        "DeviceIndex": 0,
                        "DeleteOnTermination": true,
                        "AttachmentId": "eni-attach-52193138",
                        "AttachTime": "2013-07-19T02:42:39.000Z"
                    },
                    "Groups": [
                        {
                            "GroupName": "my-sg",
                            "GroupId": "sg-903004f8"
                        }
                    ],
                    "SubnetId": "subnet-6e7f829e",
                    "OwnerId": "123456789012",
                    "PrivateIpAddress": "10.0.1.114"
                }              
            ],
            "SourceDestCheck": true,
            "Placement": {
                "Tenancy": "default",
                "GroupName": null,
                "AvailabilityZone": "us-west-2b"
            },
            "Hypervisor": "xen",
            "BlockDeviceMappings": [
                {
                    "DeviceName": "/dev/sda1",
                    "Ebs": {
                        "Status": "attached",
                        "DeleteOnTermination": true,
                        "VolumeId": "vol-877166c8",
                        "AttachTime": "2013-07-19T02:42:39.000Z"
                    }
                }              
            ],
            "Architecture": "x86_64",
            "StateReason": {
                "Message": "pending",
                "Code": "pending"
            },
            "RootDeviceName": "/dev/sda1",
            "VirtualizationType": "hvm",
            "RootDeviceType": "ebs",
            "Tags": [
                {
                    "Value": "MyInstance",
                    "Key": "Name"
                }
            ],
            "AmiLaunchIndex": 0
        }
    ]
}

For more information read the following doc on the AWS website:

https://docs.aws.amazon.com/cli/latest/userguide/cli-ec2-launch.html

Also, you can use AWS SDK for Ruby, here is a sample for creating an instance:

require 'aws-sdk-ec2'  # v2: require 'aws-sdk'
require 'base64'

# User code that's executed when the instance starts
script = ''

encoded_script = Base64.encode64(script)

ec2 = Aws::EC2::Resource.new(region: 'us-west-2')

instance = ec2.create_instances({
  image_id: 'IMAGE_ID',
  min_count: 1,
  max_count: 1,
  key_name: 'MyGroovyKeyPair',
  security_group_ids: ['SECURITY_GROUP_ID'],
  user_data: encoded_script,
  instance_type: 't2.micro',
  placement: {
    availability_zone: 'us-west-2a'
  },
  subnet_id: 'SUBNET_ID',
  iam_instance_profile: {
    arn: 'arn:aws:iam::' + 'ACCOUNT_ID' + ':instance-profile/aws-opsworks-ec2-role'
  }
})

# Wait for the instance to be created, running, and passed status checks
ec2.client.wait_until(:instance_status_ok, {instance_ids: [instance.first.id]})

# Name the instance 'MyGroovyInstance' and give it the Group tag 'MyGroovyGroup'
instance.create_tags({ tags: [{ key: 'Name', value: 'MyGroovyInstance' }, { key: 'Group', value: 'MyGroovyGroup' }]})

puts instance.id
puts instance.public_ip_address

For more information about Ruby AWS SDK read the following doc:

https://aws.amazon.com/sdk-for-ruby/

Finally, as Marco mentioned, you can use AWS CloudFormation to achieve that.

EC2 Instance with Block Device Mapping

JSON

"Ec2Instance" : {
      "Type" : "AWS::EC2::Instance", 
      "Properties" : {
        "ImageId" : { "Fn::FindInMap" : [ "AWSRegionArch2AMI", { "Ref" : "AWS::Region" }, 
                                          { "Fn::FindInMap" : [ "AWSInstanceType2Arch", { "Ref" : "InstanceType" }, "Arch" ] } ] },
        "KeyName" : { "Ref" : "KeyName" },
        "InstanceType" : { "Ref" : "InstanceType" },
        "SecurityGroups" : [{ "Ref" : "Ec2SecurityGroup" }],
        "BlockDeviceMappings" : [
          {
            "DeviceName" : "/dev/sda1",
            "Ebs" : { "VolumeSize" : "50" } 
          },{
            "DeviceName" : "/dev/sdm",
            "Ebs" : { "VolumeSize" : "100" }
          }
        ]
      }
    }

YAML

EC2Instance:
    Type: AWS::EC2::Instance
    Properties:
        ImageId: !FindInMap [ AWSRegionArch2AMI, !Ref 'AWS::Region' , !FindInMap [ AWSInstanceType2Arch, !Ref InstanceType, Arch ] ]
        KeyName: !Ref KeyName
        InstanceType: !Ref InstanceType
        SecurityGroups:
        - !Ref Ec2SecurityGroup
        BlockDeviceMappings:
        -
          DeviceName: /dev/sda1
          Ebs:
            VolumeSize: 50
        -
          DeviceName: /dev/sdm
          Ebs:
            VolumeSize: 100

For more information read the following doc on the AWS website:

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-instance.html

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/template-guide.html