Create an Auto Scaling group using parameters from an existing instance

To create an Auto Scaling group from an EC2 instance

1. Open the Amazon EC2 console at https://console.amazonaws.cn/ec2/.

2. On the navigation pane, under Instances, choose Instances, and then select an instance.

3. Choose Actions, Instance settings, Attach to Auto Scaling Group.

4. On the Attach to Auto Scaling group page, for Auto Scaling Group, enter a name for the group, and then choose Attach.

   After the instance is attached, it is considered part of the Auto Scaling group. The new Auto Scaling group is created using a new launch configuration with the same name that you specified for the Auto Scaling group. The Auto Scaling group has a desired capacity and maximum size of 1.

5. (Optional) To edit the settings for the Auto Scaling group, on the navigation pane, under Auto Scaling, choose Auto Scaling Groups. Select the check box next to the new Auto Scaling group, choose the Edit button that is above the list of groups, change the settings as needed, and then choose Update.

To use your current instance as a template

• Use the following create-auto-scaling-group command to create an Auto Scaling group, my-asg-from-instance, from the EC2 instance i-0e69cc3f05f825f4f.

  aws autoscaling create-auto-scaling-group --auto-scaling-group-name my-asg-from-instance \
    --instance-id i-0e69cc3f05f825f4f --min-size 1 --max-size 2 --desired-capacity 2

To verify that your Auto Scaling group has launched instances

• Use the following describe-auto-scaling-groups command to verify that the Auto Scaling group was created successfully.

  aws autoscaling describe-auto-scaling-groups --auto-scaling-group-name my-asg-from-instance

  The following example response shows that the desired capacity of the group is 2, the group has 2 running instances, and the launch configuration is named my-asg-from-instance.

  {
    "AutoScalingGroups":[
      {
        "AutoScalingGroupName":"my-asg-from-instance",
        "AutoScalingGroupARN":"arn",
        "LaunchConfigurationName":"my-asg-from-instance",
        "MinSize":1,
        "MaxSize":2,
        "DesiredCapacity":2,
        "DefaultCooldown":300,
        "AvailabilityZones":[
          "us-west-2a"
        ],
        "LoadBalancerNames":[],
        "TargetGroupARNs":[],
        "HealthCheckType":"EC2",
        "HealthCheckGracePeriod":0,
        "Instances":[
          {
            "InstanceId":"i-06905f55584de02da",
            "InstanceType":"t2.micro",
            "AvailabilityZone":"us-west-2a",
            "LifecycleState":"InService",
            "HealthStatus":"Healthy",
            "LaunchConfigurationName":"my-asg-from-instance",
            "ProtectedFromScaleIn":false
          },
          {
            "InstanceId":"i-087b42219468eacde",
            "InstanceType":"t2.micro",
            "AvailabilityZone":"us-west-2a",
            "LifecycleState":"InService",
            "HealthStatus":"Healthy",
            "LaunchConfigurationName":"my-asg-from-instance",
            "ProtectedFromScaleIn":false
          }
        ],
        "CreatedTime":"2020-10-28T02:39:22.152Z",
        "SuspendedProcesses":[ ],
        "VPCZoneIdentifier":"subnet-6bea5f06",
        "EnabledMetrics":[ ],
        "Tags":[ ],
        "TerminationPolicies":[
          "Default"
        ],
        "NewInstancesProtectedFromScaleIn":false,
        "ServiceLinkedRoleARN":"arn",
        "TrafficSources":[]
      }
    ]
  }

To view the launch configuration

• Use the following describe-launch-configurations command to view the details of the launch configuration.

  aws autoscaling describe-launch-configurations --launch-configuration-names my-asg-from-instance

  The following is example output:

  {
    "LaunchConfigurations":[
      {
        "LaunchConfigurationName":"my-asg-from-instance",
        "LaunchConfigurationARN":"arn",
        "ImageId":"ami-0528a5175983e7f28",
        "KeyName":"my-key-pair-uswest2",
        "SecurityGroups":[
          "sg-05eaec502fcdadc2e"
        ],
        "ClassicLinkVPCSecurityGroups":[ ],
        "UserData":"",
        "InstanceType":"t2.micro",
        "KernelId":"",
        "RamdiskId":"",
        "BlockDeviceMappings":[ ],
        "InstanceMonitoring":{
          "Enabled":true
        },
        "CreatedTime":"2020-10-28T02:39:22.321Z",
        "EbsOptimized":false,
        "AssociatePublicIpAddress":true
      }
    ]
  }             

To terminate the instance

• If you no longer need the instance, you can terminate it. The following terminate-instances command terminates the instance i-0e69cc3f05f825f4f.

  aws ec2 terminate-instances --instance-ids i-0e69cc3f05f825f4f

  After you terminate an Amazon EC2 instance, you can't restart the instance. After termination, its data is gone and the volume can't be attached to any instance. To learn more about terminating instances, see Terminate an instance in the Amazon EC2 User Guide for Linux Instances.