Multi-Region Failover with AWS Route 53 and CloudFront

We are so used to the connectivity and convenience of the modern digital world that when our favorite apps stop working, even for a few minutes, it feels like the end of the world.  

In 2021, it did seem like the world stopped working when a major AWS outage in the U.S. caused havoc in the country by taking down services for streaming platforms, food delivery apps, and airline check-ins. People missed their flights, packages got stranded, and the ripple effects were felt globally. This episode was a reminder of the fragility of these systems, which people take for granted. 

Therefore, in the modern cloud era, ensuring the availability and reliability of applications is critical for business success. Downtime due to regional failures, network outages, or infrastructure issues can severely affect user experience and business operations.  

To mitigate such risks, implementing a multi-region failover strategy is essential. AWS offers powerful tools like Route 53 and CloudFront to seamlessly implement multi-region failover. 

In this blog, we’ll walk you through the process of setting up a multi-region failover solution using AWS Route 53 for DNS routing and AWS CloudFront for content delivery. This approach ensures your application remains highly available and provides users with low-latency access even during a regional failure. 

Understanding AWS Regions 

Amazon uses the concept of Regions in its AWS offerings. An AWS Region is a cluster of data centers in a specific geographic area, such as the Northeastern United States or Western Europe. And each AWS Region consists of at least three isolated and physically separate Availability Zones (AZs). 

AZs are physical data centers within an AWS Region. These data centers are physically close enough to each other to provide fast communication but far enough apart to avoid being affected by the same problems like outages. Each AZ has its own power, security, and maintenance support. 

All AZs in an AWS Region are interconnected with high-bandwidth and low-latency networking. This helps AWS Regions to keep your applications available and resilient even when something goes wrong.  

Users prefer to choose an AWS Region that is geographically close to theirs. This 
reduces latency because data reaches users more quickly. 

Here is a list of some of the AWS Regions: 

What is multi-region failover? 

Multi-region failover is a strategy used to ensure that if a particular AWS Region becomes unavailable or experiences issues, traffic is automatically redirected to a backup region.  

In a multi-region failover setup, your application and its associated infrastructure are deployed across multiple AWS Regions. For this purpose, a cloned version of the app is maintained in a secondary failover region, including the app’s compute, storage, and networking. 

If your primary AWS Region experiences an outage or severe degradation, traffic can 
be immediately switched to the secondary region. This setup helps prevent downtime, provides improved availability, and enables better disaster recovery for critical services. 

Why do AWS Regions fail? 

AWS has a strong track record for availability, but no system is perfect. Issues can arise due to several factors that can lead to AZs or an entire region becoming unavailable. These factors can include: 

1. Natural disasters 

Events like earthquakes, floods, hurricanes, or severe storms can impact data centers in a specific geographic region. In 2011, a lightning strike hit one of the AWS data centers in Dublin, which caused a 24–48-hour outage in the said AZ. 

2. Configuration errors 

Internal misconfigurations can severely disrupt the availability of AWS offerings. The 2021 AWS outage in the U.S. was caused by a failure within the AWS’s internal network traffic management system. 

These kinds of issues usually have the most fallout because they are hard to detect until something breaks.  

3. Power outages 

Power outages are among the most common causes of AWS shortages in recent years. Large-scale power failures, whether due to natural causes, grid failures, or human error, can affect entire data centers or even multiple data centers within a region. 

How to setup multi-region failover with Amazon Route 53 and CloudFront  

With AWS, you can set up a failover mechanism between regions using Amazon Route 53 for DNS management and Amazon CloudFront for content delivery. 

Why use Route 53 and CloudFront among other options for multi-region failover? Well, that is because these are powerful services that, when combined, allow for intelligent traffic routing and content delivery 

1. AWS Route 53 

It’s a highly scalable and reliable DNS service that allows you to route end users to various resources based on DNS queries. It supports routing traffic to multiple regions using latency-based routing, geolocation routing, and weighted routing policies. 

2. Amazon CloudFront 

CloudFront is a Content Delivery Network (CDN) that delivers content, such as websites, APIs, and videos to users with low latency and high transfer speeds. It integrates well with Route 53 to help achieve failover, delivering content from the nearest available region when there’s an issue.

Key steps to implement multi-region failover with AWS Route 53 and CloudFront 

Step 1: Set up two AWS Regions 

For multi-region failover, you’ll need resources in two AWS regions. These can be similar infrastructure setups in each region, such as EC2 instances, S3 buckets, databases, or other services that power your application. 

For example: 

• Region A (Primary Region): us-east-1 
• Region B (Secondary Region): us-west-2 

Step 2: Create and configure CloudFront distributions 

1. Create CloudFront distributions for both Regions: You need to create a separate CloudFront distribution for each region to serve content from the nearest AWS edge location. 

• For Region A, create a CloudFront distribution that points to your resources (EC2 instance, S3 bucket, etc.). 
• For Region B, create a similar distribution that serves the same resources but from the secondary region. 

2. Set up origin failover: CloudFront supports automatic origin failover. This means that if the primary origin (in Region A) becomes unavailable, CloudFront will automatically switch to the secondary origin (in Region B). To configure this: 

• In the CloudFront settings, configure both origins (primary and secondary). 
• Set up the failover mechanism in the origin settings. CloudFront will attempt to fetch content from the primary origin, and if it is unavailable, it will switch to the secondary origin. 

Step 3: Set Up Amazon Route 53 for DNS management 

Amazon Route 53 will be responsible for routing DNS traffic to the appropriate CloudFront distribution based on the health of each region. Here’s how to configure Route 53 for failover: 

1. Create health checks: Route 53 offers health checks that can monitor the health of your CloudFront distributions. Configure health checks to periodically monitor the status of your distributions in both regions. 

• Set up a health check for the CloudFront distribution in Region A (primary region). 
• Set up a similar health check for the CloudFront distribution in Region B (secondary region). 
• Route 53 will use these health checks to determine which distribution is healthy and direct traffic to the healthy region. 

2. Create a DNS record with failover routing policy: 

• In the Route 53 dashboard, create a new record set for your domain (e.g., www.example.com). 
• Choose failover routing as the routing policy. 
• Create two records: one for the primary region and one for the secondary region. 

For example: 

• Primary record (Region A): Set this record as the primary failover record, associating it with the CloudFront distribution in Region A. 
• Secondary record (Region B): Set this record as the secondary failover record, associating it with the CloudFront distribution in Region B. 

3. Associate Health Checks: When configuring the record sets, link the health checks created earlier. This ensures that if Route 53 detects an unhealthy CloudFront distribution in Region A, it will failover to the CloudFront distribution in Region B. 

Step 4: Test the multi-region failover setup 

After configuring the multi-region failover, it’s essential to test that the failover mechanism works as expected: 

1. Simulate a failure: You can simulate a failure in Region A (e.g., by stopping the EC2 instance or removing resources) and observe how Route 53 reroutes traffic to Region B. 
2. Monitor traffic: Use tools like AWS CloudWatch to monitor the health of the regions and ensure that Route 53 is correctly routing traffic to the healthy region. 
3. Check user experience: From a user’s perspective, they should not experience any downtime or latency issues when traffic is routed to the secondary region. Ensure that CloudFront serves content with minimal disruption. 

Step 5: Optimize and maintain 

1. Set up auto scaling: For a fully robust solution, configure auto-scaling in both regions to ensure that your application can handle changes in traffic demand. 
2. Use AWS Global Accelerator: For faster failover detection and reduced latency, you can incorporate AWS Global Accelerator, which uses the AWS global network to route traffic to the optimal region, reducing latency during a failover. 
3. Ensure proper logging and monitoring: Use Amazon CloudWatch and AWS CloudTrail to keep track of the health of your infrastructure, detect potential issues early, and monitor the failover process. 

Benefits of multi-region failover with Route 53 and CloudFront 

1. High availability: Multi-region failover ensures that if one region goes down, traffic is automatically redirected to another region, providing continuous availability of your application. 
2. Improved performance: AWS CloudFront ensures content is delivered to users from the nearest edge location, reducing latency and improving user experience. 
3. Disaster recovery: This setup acts as a disaster recovery solution. Even in the case of region-wide failures, users will still be able to access the application via the backup region. 
4. Scalability: With the integration of AWS services like CloudFront and Route 53, the failover mechanism can easily scale to accommodate large numbers of users globally. 
5. Cost-effective: AWS provides pay-as-you-go pricing, meaning you only pay for the resources you use. Setting up failover is an efficient way to ensure high availability without the need for redundant infrastructure that is always running.

Conclusion 

Downtime is inevitable but being unprepared for it is optional. Businesses that operate in the cloud without a failover plan are gambling with user trust and revenue. AWS offers building blocks to stay online even when things go wrong, but it’s up to you to assemble them wisely. 

Implementing multi-region failover with AWS Route 53 and CloudFront is an effective strategy for ensuring high availability, improving disaster recovery capabilities, and enhancing the user experience. A well-implemented multi-region setup using Route 53 and CloudFront doesn’t eliminate every risk, but it dramatically reduces the blast radius when failures occur. 

Using these services, you can ensure that your infrastructure remains resilient in the face of region-specific failures, while also providing users with the best possible experience, no matter where they are located. 

Xavor’s managed cloud services for AWS and Azure manage your cloud infrastructure with diligence. Deploy a resilient multi-region failover mechanism or optimize your AWS resources with our seasoned cloud experts.  

Contact us at [email protected] to start exploring options.