automatically-attach-eip-elastic-ip-with-ec2

# https://stackoverflow.com/questions/53919530/aws-ec2-user-data-script-to-allocate-elastic-ip

{
"Version": "2012-10-17",
"Statement": [
    {
        "Effect": "Allow",
        "Action": [
            "ec2:DescribeAddresses",
            "ec2:AllocateAddress",
            "ec2:DescribeInstances",
            "ec2:AssociateAddress"
        ],
        "Resource": "*"
    }
]
}



#!/bin/bash
INSTANCE_ID=$(curl -s http://169.254.169.254/latest/meta-data/instance-id)
MAXWAIT=3
ALLOC_ID=<your eip allocation id>
AWS_DEFAULT_REGION=<your region>

export AWS_DEFAULT_REGION

# Make sure the EIP is free
echo "Checking if EIP with ALLOC_ID[$ALLOC_ID] is free...."
ISFREE=$(aws ec2 describe-addresses --allocation-ids $ALLOC_ID --query Addresses[].InstanceId --output text)
STARTWAIT=$(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)
    fi
done

# Now we can associate the address
echo Running: aws ec2 associate-address --instance-id $INSTANCE_ID --allocation-id $ALLOC_ID --allow-reassociation}
aws ec2 associate-address --instance-id $INSTANCE_ID --allocation-id $ALLOC_ID