Swaps volumes of two EC2 instance using AWS CLI. Includes Terraform to spawn two ec2 instances for testing.

swap-ec2-volumes.sh

#!/bin/bash

AWS_PROFILE="YOUR-AWS-PROFILE"
AWS_REGION="YOUR-AWS-REGION"

# OLD INSTANCE INFO
OLD_INSTANCE_ID="i-0123456789abcdef0"
OLD_INSTANCE_VOLUME_ID="vol-0123456789abcdef0"
OLD_INSTANCE_MOUNT_POINT="/dev/sda1"

# NEW INSTANCE INFO
NEW_INSTANCE_ID="i-0fedcba9876543210"
NEW_INSTANCE_VOLUME_ID="vol-0fedcba9876543210"
NEW_INSTANCE_MOUNT_POINT="/dev/sda1"

stop_detach_old() {
    echo " >>> Stop and detach OLD instance started..."

    aws ec2 stop-instances \
    --instance-ids "${OLD_INSTANCE_ID}" \
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text

    echo " >>> Wait for the OLD instance to be stopped..."

    aws ec2 wait instance-stopped \
    --instance-ids "${OLD_INSTANCE_ID}" \
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text

    echo " >>> Old instance is stopped!"
    
    aws ec2 detach-volume \
    --volume-id "${OLD_INSTANCE_VOLUME_ID}" \
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text

    echo " >>> Wait for the OLD volume to become available..."

    aws ec2 wait volume-available \
    --volume-ids "${OLD_INSTANCE_VOLUME_ID}" \
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text

    echo " >>> Old volume is now available!"

    echo " >>> Stop and detach OLD instance completed!"
}


stop_detach_new() {
    echo " >>> Stop and detach NEW instance started..."

    aws ec2 stop-instances \
    --instance-ids "${NEW_INSTANCE_ID}" \
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text

    echo " >>> Wait for the NEW instance to be stopped..."

    aws ec2 wait instance-stopped \
    --instance-ids "${NEW_INSTANCE_ID}" \
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text

    echo " >>> Old instance is stopped!"
    
    aws ec2 detach-volume \
    --volume-id "${NEW_INSTANCE_VOLUME_ID}" \
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text

    echo " >>> Wait for the NEW volume to become available..."

    aws ec2 wait volume-available \
    --volume-ids "${NEW_INSTANCE_VOLUME_ID}" \
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text

    echo " >>> Old volume is now available!"

    echo " >>> Stop and detach NEW instance completed!"
}

attach_start_new() {
    echo " >>> Attach and start NEW instance started..."

    aws ec2 attach-volume \
    --device "${OLD_INSTANCE_MOUNT_POINT}" \
    --instance-id "${NEW_INSTANCE_ID}" \
    --volume-id "${OLD_INSTANCE_VOLUME_ID}"\
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text

    echo " >>> Wait for the OLD volume to attach to the NEW instance..."

    aws ec2 wait volume-in-use \
    --volume-ids "${OLD_INSTANCE_VOLUME_ID}" \
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text

    echo " >>> OLD volume is now attached to the NEW instance!"
    
    aws ec2 start-instances \
    --instance-ids "${NEW_INSTANCE_ID}" \
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text

    echo " >>> Attach and start NEW instance completed!"
}

attach_start_old() {
    echo " >>> Attach and start OLD instance started..."

    aws ec2 attach-volume \
    --device "${NEW_INSTANCE_MOUNT_POINT}" \
    --instance-id "${OLD_INSTANCE_ID}" \
    --volume-id "${NEW_INSTANCE_VOLUME_ID}" \
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text

    echo " >>> Wait for the NEW volume to attach to the OLD instance...."

    aws ec2 wait volume-in-use \
    --volume-ids "${NEW_INSTANCE_VOLUME_ID}" \
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text
    
    echo " >>> NEW volume is now attached to the OLD instance!"

    aws ec2 start-instances \
    --instance-ids "${OLD_INSTANCE_ID}" \
    --profile "${AWS_PROFILE}" \
    --region "${AWS_REGION}" \
    --output text

    echo " >>> Attach and start OLD instance completed!"
}

stop_detach_old

stop_detach_new

attach_start_new

attach_start_old

echo "DONE!"

terraform-ec2-instances.tf

provider "aws" {
  region  = "YOUR-AWS-REGION"
  profile = "YOUR-AWS-PROFILE"
}

data "aws_ami" "ubuntu" {
  most_recent = true

  filter {
    name   = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-focal-20.04-amd64-server-*"]
  }

  filter {
    name   = "virtualization-type"
    values = ["hvm"]
  }

  owners = ["099720109477"] # Canonical
}

resource "aws_vpc" "vpc" {
  cidr_block = "172.16.0.0/16"

  tags = {
    Name = "EC2-volume-swap"
  }
}

resource "aws_subnet" "subnet" {
  vpc_id            = aws_vpc.vpc.id
  cidr_block        = "172.16.10.0/24"
  availability_zone = "eu-central-1a"

  tags = {
    Name = "EC2-volume-swap"
  }
}

resource "aws_instance" "old_server" {
  ami           = data.aws_ami.ubuntu.id
  instance_type = "t2.micro"

  network_interface {
    network_interface_id = aws_network_interface.old_server.id
    device_index         = 0
  }

  tags = {
    Name = "Old Server"
  }
}

resource "aws_network_interface" "old_server" {
  subnet_id   = aws_subnet.subnet.id
  private_ips = ["172.16.10.100"]

  tags = {
    Name = "primary_network_interface"
  }
}

resource "aws_instance" "new_server" {
  ami           = data.aws_ami.ubuntu.id
  instance_type = "t2.micro"

  network_interface {
    network_interface_id = aws_network_interface.new_server.id
    device_index         = 0
  }

  tags = {
    Name = "New Server"
  }
}

resource "aws_network_interface" "new_server" {
  subnet_id   = aws_subnet.subnet.id
  private_ips = ["172.16.10.200"]

  tags = {
    Name = "primary_network_interface"
  }
}