Autoscaling Group
An AWS Autoscaling Group (ASG) is a logical collection of Amazon EC2 instances that are treated as a single scalable resource. It automatically adjusts the number of running instances to maintain a desired capacity, respond to demand spikes, enforce health‐based replacement, and support rolling updates. Configuration parameters such as minimum, maximum and desired instance counts, scaling policies, health checks and lifecycle hooks are all defined at the group level.
Further information is available in the official AWS documentation: https://docs.aws.amazon.com/autoscaling/ec2/userguide/AutoScalingGroup.html
Terrafrom Mappings:
aws_autoscaling_group.arn
Supported Methods
GET
: Get an Autoscaling Group by nameLIST
: List Autoscaling GroupsSEARCH
: Search for Autoscaling Groups by ARN
Possible Links
ec2-launch-template
An ASG normally references a launch template that describes how each EC2 instance should be configured (AMI, instance type, security groups, IAM instance profile, user data, etc.). Therefore the ASG is linked to its associated ec2-launch-template
.
elbv2-target-group
ASGs can be attached to one or more ALB/NLB target groups so that their member instances are automatically registered and deregistered as they scale. The link shows which elbv2-target-group
(s) an ASG feeds.
ec2-instance
The running EC2 instances that currently belong to an ASG are directly related to it. Overmind surfaces this connection so you can see which ec2-instance
objects are under the control of a specific ASG.
iam-role
Autoscaling uses an AWS service-linked role (typically AWSServiceRoleForAutoScaling
) to perform scaling and health check actions on your behalf. Additionally, the launch template referenced by the ASG may specify an instance profile containing an IAM role for the launched instances. Both relationships are captured via the iam-role
link.
ec2-placement-group
If the ASG’s launch template specifies a placement group, any instances it launches will be placed accordingly for improved networking performance or spread. The link reveals the ec2-placement-group
associated with the ASG.