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My Journey Migrating from IPv4 to IPv6 on AWS

As cloud hosting costs continue to evolve, it’s essential to review and optimize our infrastructure. Recently, I embarked on a journey to transition from IPv4 to IPv6 on my AWS-hosted website, primarily to eliminate the cost associated with AWS Elastic IPs. Here’s a recap of my experience, challenges, and ultimate success.

Why Migrate to IPv6?

AWS charges for Elastic IPs (EIP) even when they are associated with a running EC2 instance, making it a recurring cost that can be avoided. By adopting IPv6, I aimed to:

  • Reduce expenses: Stop paying for Elastic IPs.
  • Modernize the infrastructure: Future-proof my website’s networking.
  • Enhance accessibility: Ensure the website is reachable over both IPv4 and IPv6 as more networks adopt the newer protocol.

Initial Setup: My AWS Environment

My website, hosted on an AWS EC2 instance, runs a LAMP stack on Amazon Linux 2. The setup includes Apache, MariaDB, and PHP, supporting a WordPress-based site. Before the migration, the site was accessible only via IPv4, with an AWS Elastic IP attached.

The Migration Process

Here’s a step-by-step breakdown of how I migrated to IPv6:

  1. Enable IPv6 in the VPC
    • I started by adding an IPv6 CIDR block to the VPC associated with my EC2 instance. AWS offers multiple options, but for simplicity, I chose an Amazon-provided IPv6 CIDR block.
  2. Configure the Subnet for IPv6
    • Next, I allocated an IPv6 CIDR block to the subnet where my instance resides. This assignment allowed the EC2 instance to obtain an IPv6 address.
  3. Update the Routing Table
    • One key step was updating the VPC’s routing table. I added a route for ::/0 with the Internet Gateway as the target. While there was already a route for 0.0.0.0/0 (IPv4), the IPv6 traffic required this new route.
  4. Modify Apache Configuration for IPv6
    • I adjusted the Apache httpd.conf settings:
      • Replaced Listen 80 with Listen [::]:80
      • Replaced Listen 443 with Listen [::]:443
    • However, I retained the <VirtualHost *:80> and <VirtualHost *:443> blocks, as they worked fine for both IPv4 and IPv6 connections.
  5. Update DNS Settings
    • I added an AAAA record in my DNS configuration to ensure that the domain resolves to the server’s IPv6 address. This step was crucial for making the website accessible over IPv6.
  6. Restart Apache
    • After making these changes, I restarted the Apache service. Everything was configured properly, and the web server could now handle requests over IPv6!

Challenges Faced and Lessons Learned

  1. Routing Table Misconfiguration
    • Initially, the IPv6 setup didn’t work. I realized I had missed adding the ::/0 route in the routing table, which is crucial for directing IPv6 traffic to the Internet Gateway.
  2. Firewall and Security Group Settings
    • Ensuring security groups allowed IPv6 traffic on ports 80 (HTTP) and 443 (HTTPS) was another important task. Always double-check inbound and outbound rules when dealing with new protocols.
  3. Understanding Apache’s Dual-Stack Configuration
    • Although I only needed to add Listen [::]:80 and Listen [::]:443, I was initially unsure if I needed to update <VirtualHost> settings for IPv6. Fortunately, the existing configuration worked without modification.

The Result: Cost Savings and Modernization

With everything set up correctly, my website is now accessible over both IPv4 and IPv6. More importantly, I no longer need to pay for an AWS Elastic IP, leading to tangible cost savings. The transition has made my website’s networking stack future-proof while ensuring broader accessibility as more users move to IPv6.

Conclusion

Migrating from IPv4 to IPv6 may seem daunting, but with a clear objective, proper planning, and attention to details like routing and DNS configuration, the process is smooth and rewarding. If you’re looking to cut down on cloud costs or modernize your setup, I highly recommend considering an IPv6 migration.

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Working with AWS CloudFormation is FUN!!!

Working with CloudFormation to code your Infrastructure is fun and easy. Thanks to the visual designer that comes with the tool which work like most IDE (e.g. NetBeans, Eclipse) to develop a program.

The designer has a drag and drop interface, i.e canvas and an editor (text) section. The latter has a Template tab and Components tab which is subdivided into Parameters, Mappings, Conditions, Metadata, and Outputs sections.

The canvas has all the list of resource types you need and this helps you get more familiar with AWS and how they can be interrelated to other services.

Likewise, the editor section also has an automatic suggestion of intrinsic functions and resource reference parameters for the field values in your template using the CTRL+Space key.

Clueless how to start? Upload a sample template and reviewing it will help you understand and architect your infrastructure easier if you’re just starting to learn the tool.

One style I do to learn coding (e.g. python) was to fork a code and deconstruct it. Thanks to AWS, they have bunch of sample templates to copy and deploy. The tool comes with built-in sample templates and some of which is linked here.

Here’s a sample solution I copied from AWS list of template which is linked here.

* Template Name – WordPress scalable and durable.

* Description: Installs and deploys WordPress on to Amazon EC2 instances in an Auto Scaling group with a multi-AZ Amazon RDS database instance for storage.

With some modification – positioning of the resources, the stack will look like this:

The code which is in json format can be found here.

So, once template is validated, keyed-in parameter values (e.g. instance-type, database name, password), a summary is presented for you to review before hitting the create button.  The stack should be completed in  a few minutes.

Aside from making template from scratch or samples, you can create a template of your existing infrastructure.  You can use the CloudFormer tool to build it. This is like reverse engineering your Infrastructure. This means you can capture and redeploy applications you already have running.

To do this, click Launch CloudFormer and create an AWS CloudFormation stack that runs the CloudFormer tool. After the stack creation is complete, navigate to the CloudFormer URL available on the Outputs tab.

Finally, BEST PRACTICES are recommended to help you use CloudFormation effectively and securely.

Happy coding.