Assign a static elastic IP to an instance in Autoscaling Group - amazon-web-services

Question

I have one instance in ASG, I need to assign an elastic ip that instance. Now when the instance health check fails, the newly launched instance should have the same elastic IP. The IAM role and everything is in the correct order.

Answer 1

INSTANCE_ID=$(curl -s http://169.254.169.254/latest/meta-data/instance-id)
MAXWAIT=3
ALLOC_ID=${IPAddresses}
echo "Checking if EIP with ALLOC_ID[$ALLOC_ID] is free...."
ISFREE=$(aws ec2 describe-addresses --allocation-ids $ALLOC_ID --query Addresses[].InstanceId --output text --region ${AWS::Region})
STARTWAIT=$(date +%s)
while [ ! -z "$ISFREE" ]; do
if [ "$(($(date +%s) - $STARTWAIT))" -gt $MAXWAIT ]; then
echo "WARNING: We waited 30 seconds, we're forcing it now."
ISFREE=""
else
echo "Waiting for EIP with ALLOC_ID[$ALLOC_ID] to become free...."
sleep 3
ISFREE=$(aws ec2 describe-addresses --allocation-ids $ALLOC_ID --query Addresses[].InstanceId --output text --region ${AWS::Region})
fi
done
echo Running: aws ec2 associate-address --instance-id $INSTANCE_ID --allocation-id $ALLOC_ID --allow-reassociation --region ${AWS::Region}}
aws ec2 associate-address --instance-id $INSTANCE_ID --allocation-id $ALLOC_ID --allow-reassociation --region ${AWS::Region}
yum install jq -y

Answer 2

Not sure how to take that IP from the resource itself and pass it as a user data in Launch configuration.
In the CFN, it would look similar to the following:
Resources:
MyEIP:
Type: AWS::EC2::EIP
Properties: {}
MyLaunchTemplate:
Type: AWS::EC2::LaunchTemplate
Properties:
UserData:
Fn::Base64: !Sub |
#!/bin/bash -xe
EIP_IP=${MyEIP}
echo ${!EIP_IP}
# use aws cli to attach EIP_IP to the instance
Instance role would be required as well with permissions to attach the EIP.
From docs about !Ref which will be used when EIP_IP=${MyEIP}:
When you pass the logical ID of this resource to the intrinsic Ref function, Ref returns the Elastic IP address.

Answer 3

With EC2 & Auto scaling, You need using user data in EC2 to Auto Attach Elastic IP to EC2 Instance For Auto scaling
#!/bin/bash
aws configure set aws_access_key_id "XYZ..."
aws configure set aws_secret_access_key "ABC..."
aws configure set region "ap-..."
aws ec2 associate-address --instance-id "$(curl -X GET "http://169.254.169.254/latest/meta-data/instance-id")" --public-ip your_elastic_IP
Note: you should create new user & IAM have only permission associate-address to create/get aws key
Hope it be help you :)