Examples for working with Elastic Load Balancing using the AWS CLI

Use the AWS Command Line Interface (AWS CLI) to attach, detach, and describe load balancers and target groups, add and remove Elastic Load Balancing health checks, and change which Availability Zones are enabled.

This topic shows examples of AWS CLI commands that perform common tasks for Amazon EC2 Auto Scaling.

Attach your target group or Classic Load Balancer

Use the following create-auto-scaling-group command to create an Auto Scaling group and simultaneously attach a target group by specifying its Amazon Resource Name (ARN). The target group can be associated with an Application Load Balancer, a Network Load Balancer, or a Gateway Load Balancer.

Replace the sample values for --auto-scaling-group-name, --vpc-zone-identifier, --min-size, and --max-size. For the --launch-template option, replace my-launch-template and 1 with the name and version of a launch template for your Auto Scaling group. For the --traffic-sources option, replace the sample ARN with the ARN of a target group for an Application Load Balancer, Network Load Balancer, or Gateway Load Balancer.

aws autoscaling create-auto-scaling-group --auto-scaling-group-name my-asg \
  --launch-template LaunchTemplateName=my-launch-template,Version='1' \
  --vpc-zone-identifier "subnet-5ea0c127,subnet-6194ea3b,subnet-c934b782" \
  --min-size 1 --max-size 5 \
  --traffic-sources "Identifier=arn:aws:elasticloadbalancing:region:account-id:targetgroup/my-targets/12345678EXAMPLE1"

Use the attach-traffic-sources command to attach additional target groups to the Auto Scaling group after it's created.

The following command adds another target group to the same group.

aws autoscaling attach-traffic-sources --auto-scaling-group-name my-asg \
  --traffic-sources "Identifier=arn:aws:elasticloadbalancing:region:account-id:targetgroup/my-targets/12345678EXAMPLE2"

Alternatively, to attach a Classic Load Balancer to your group, specify the --traffic-sources and --type options when you use create-auto-scaling-group or attach-traffic-sources, as in the following example. Replace my-classic-load-balancer with the name of a Classic Load Balancer. For the --type option, specify a value of elb.

--traffic-sources "Identifier=my-classic-load-balancer" --type elb

Describe your target groups or Classic Load Balancers

To describe the load balancers or target groups attached to your Auto Scaling group, use the following describe-traffic-sources command. Replace my-asg with the name of your group.

aws autoscaling describe-traffic-sources --auto-scaling-group-name my-asg

The example returns the ARN of the Elastic Load Balancing target groups that you attached to the Auto Scaling group.

{
    "TrafficSources": [
        {
            "Identifier": "arn:aws:elasticloadbalancing:region:account-id:targetgroup/my-targets/12345678EXAMPLE1",
            "State": "InService",
            "Type": "elbv2"
        },
        {
            "Identifier": "arn:aws:elasticloadbalancing:region:account-id:targetgroup/my-targets/12345678EXAMPLE2",
            "State": "InService",
            "Type": "elbv2"
        }
    ]
}

For an explanation of the State field in the output, see Verify the attachment status of your load balancer.

Add Elastic Load Balancing health checks

To add Elastic Load Balancing health checks to the health checks that your Auto Scaling group performs on instances, use the following update-auto-scaling-group command and specify ELB as the value for the --health-check-type option. Replace my-asg with the name of your group.

aws autoscaling update-auto-scaling-group --auto-scaling-group-name my-asg \
  --health-check-type "ELB"

New instances often need time for a brief warmup before they can pass a health check. If the grace period doesn't provide enough warmup time, the instances might not appear ready to serve traffic. Amazon EC2 Auto Scaling might consider those instances unhealthy and replace them.

To update the health check grace period, use the --health-check-grace-period option when you use update-auto-scaling-group, as in the following example. Replace 300 with the number of seconds to keep new instances in service before terminating them if they're found to be unhealthy.

--health-check-grace-period 300

For more information, see Health checks for instances in an Auto Scaling group.

Change your Availability Zones

Changing your Availability Zones has some limitations that you should be aware of. For more information, see Add an Availability Zone.

Detach your target group or Classic Load Balancer

The following detach-traffic-sources command detaches a target group from your Auto Scaling group when you no longer need it.

For the --auto-scaling-group-name option, replace my-asg with the name of your group. For the --traffic-sources option, replace the sample ARN with the ARN of a target group for an Application Load Balancer, Network Load Balancer, or Gateway Load Balancer.

aws autoscaling detach-traffic-sources --auto-scaling-group-name my-asg \
  --traffic-sources "Identifier=arn:aws:elasticloadbalancing:region:account-id:targetgroup/my-targets/1234567890123456"

To detach a Classic Load Balancer from your group, specify the --traffic-sources and --type options, as in the following example. Replace my-classic-load-balancer with the name of a Classic Load Balancer. For the --type option, specify a value of elb.

--traffic-sources "Identifier=my-classic-load-balancer" --type elb

Remove Elastic Load Balancing health checks

To remove Elastic Load Balancing health checks from your Auto Scaling group, use the following update-auto-scaling-group command and specify EC2 as the value for the --health-check-type option. Replace my-asg with the name of your group.

aws autoscaling update-auto-scaling-group --auto-scaling-group-name my-asg \
  --health-check-type "EC2"

For more information, see Health checks for instances in an Auto Scaling group.

Legacy commands

The following examples show how you can use legacy CLI commands to attach, detach, and describe load balancers and target groups. They remain in this document as a reference for any customers who want to use them. We continue to support the legacy CLI commands, but we recommend that you use the new "traffic sources" CLI commands, which can attach and detach multiple traffic sources types. You can use both the legacy CLI commands and the "traffic sources" CLI commands on the same Auto Scaling group.

aws autoscaling create-auto-scaling-group --auto-scaling-group-name my-asg \
  --launch-template LaunchTemplateName=my-launch-template,Version='1' \
  --vpc-zone-identifier "subnet-5ea0c127,subnet-6194ea3b,subnet-c934b782" \
  --target-group-arns "arn:aws:elasticloadbalancing:region:account-id:targetgroup/my-targets/1234567890123456" \
  --min-size 1 --max-size 5

aws autoscaling attach-load-balancer-target-groups --auto-scaling-group-name my-asg \
  --target-group-arns "arn:aws:elasticloadbalancing:region:account-id:targetgroup/my-targets/1234567890123456"

aws autoscaling create-auto-scaling-group --auto-scaling-group-name my-asg \
  --launch-configuration-name my-launch-config \
  --vpc-zone-identifier "subnet-5ea0c127,subnet-6194ea3b,subnet-c934b782" \
  --load-balancer-names "my-load-balancer" \
  --min-size 1 --max-size 5

aws autoscaling attach-load-balancers --auto-scaling-group-name my-asg \
  --load-balancer-names my-lb

aws autoscaling describe-load-balancer-target-groups --auto-scaling-group-name my-asg

aws autoscaling describe-load-balancers --auto-scaling-group-name my-asg

aws autoscaling detach-load-balancer-target-groups --auto-scaling-group-name my-asg \
  --target-group-arns "arn:aws:elasticloadbalancing:region:account-id:targetgroup/my-targets/1234567890123456"

aws autoscaling detach-load-balancers --auto-scaling-group-name my-asg \
  --load-balancer-names my-lb