Amazon_EC2_8

Ensure each Auto-Scaling Group is configured for multiple Availability Zones

Description

Auto Scaling helps maintain application availability and allows you to scale your Amazon EC2 capacity up or down automatically according to conditions you define.You can use Auto Scaling to help ensure that you are running your desired number of Amazon EC2 instances or can automatically increase the number of Amazon EC2 instances during demand spikes to maintain performance and decrease capacity during lulls to reduce costs.
These properties can be defined within the Auto-Scaling Group configuration.

Remediation

Using the Amazon Unified CLI:

  • List all the subnets and the associated Availability Zones from the application VPC:
    aws ec2 describe-subnets –query “Subnets[?VpcId == ‘application_vpc’].{VPC:VpcId,
    Subnet:SubnetId, AZ:AvailabilityZone, CIDR:CidrBlock}”
  • Update AutoScaling Group to include more than 1 Availability Zones within the
    same VPC:
    aws autoscaling update-auto-scaling-group –auto-scaling-group-name
    <autoscaling_group_name> –availability-zones <application_az>

References:

  1. http://docs.aws.amazon.com/cli/latest/reference/autoscaling/update-auto-scaling-group.html
  2. http://docs.aws.amazon.com/cli/latest/reference/ec2/describe-subnets.html

Service

EC2

Severity

Low

Compliance

Mapping

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