Building a Scalable, Secure, and High-Availability Enterprise WordPress on AWS

WordPress powers over 40% of websites globally, ranging from small blogs to enterprise-grade platforms. WordPress is simple to launch for a personal blog, but scaling it to handle millions of users while maintaining high availability and robust security requires careful design.

In this post, we’ll share insights for deploying a scalable and secure WordPress deployment on AWS, drawing directly from our experience. From choosing the compute platform to optimizing caching and security, every decision we made was based on real-world lessons learned from deploying mission-critical and high-volume WordPress sites.

Choosing the Compute Platform

When evaluating the best computing platform for WordPress, we considered all the usual suspects: EC2, EKS, ECS, Elastic Beanstalk, and even Lightsail. Each had its merits, but ECS Fargate stood out for its ability to meet our needs with minimal operational overhead.

With Fargate, we don’t have to worry about managing servers. Instead, we can focus entirely on our application, knowing AWS handles the underlying infrastructure. We also found that Fargate scales seamlessly, making it a perfect fit for unpredictable traffic spikes.

We’ve used EC2 for WordPress in the past, and while it offers flexibility and cost savings, the time spent on maintenance—like patching and capacity management—was a significant drawback. Similarly, although EKS is powerful, spinning up an entire Kubernetes cluster just for WordPress felt like overkill.

Our takeaway? ECS Fargate strikes the right balance between scalability, ease of use, and cost-effectiveness, especially when your goal is to “set it and forget it.”

Selecting the Right WordPress Container Image

Once we decided on ECS, the next step was choosing the right WordPress container image. We tested several options, including the official WordPress image and Bitnami’s Apache and NGINX versions. From our experience, Bitnami WordPress with NGINX provided the most consistent performance under heavy load.

While Apache can excel in specific scenarios, especially with certain modules, NGINX’s lightweight and fast architecture aligns better with our scalability needs.

Bitnami’s images also allowed automation with Terraform. Instead of spending time on manual post-deployment configurations, we could deploy a customized container with a single command.

Scaling WordPress Instances

Scalability is crucial for handling traffic spikes without compromising performance. With ECS, WordPress instances can scale diagonally (vertically and horizontally) by deploying tasks behind an Application Load Balancer (ALB). This ensures seamless distribution of traffic and redundancy across multiple availability zones.

However, WordPress is inherently a stateful application. Files in /wp-content/ and configurations in wp-config.php need to be consistent across all instances. To solve this, the common approach is to use Elastic File System (EFS) as shared storage.

EFS is highly available across multiple availability zones and automatically scales with demand. It ensures every WordPress instance has access to the same content, eliminating inconsistencies. For optimal performance, we recommend following AWS’s EFS mount settings and enabling noatime.

For teams dealing with exceptionally high traffic, EFS’s ability to handle millions of read operations per second is a game-changer. Finally, we recommend setting up an EFS backup policy to enable regular backups and define the retention period.

Building a Resilient Database Layer

WordPress relies on MySQL or MariaDB, and AWS provides several hosting options: RDS, Aurora, or even self-managed databases on EC2. For enterprise-grade deployments, Amazon Aurora MySQL is the top choice.

Aurora’s automatic replication across availability zones gave us the peace of mind we needed for high availability. We’ve seen it failover in under 60 seconds during testing, and its performance under load has been stellar. Its storage scales automatically up to 128TB without downtime, and its compute layer can be scaled vertically to 128 vCPUs, 1024 GiB of memory and 16,000 concurrent connections.

To further enhance connection efficiency, we recommend deploying RDS Proxy. This reduces database overhead by pooling connections, especially when handling multiple WordPress instances.

Horizontal scaling of Aurora is also possible with read replicas, although WordPress doesn’t natively support using separate read and write endpoints. Tools like HyperDB can help by routing read queries to replicas, enabling horizontal scaling to millions of reads per second.

Enhancing Performance with Caching

A well-designed caching strategy is essential for high-performance WordPress deployments. By layering caching at multiple levels, we significantly reduce the load on the database and application servers.

At the CDN level, we use CloudFront as a reverse proxy to serve static and dynamic content. Static content such as images, CSS, and JavaScript typically stored under /wp-content/ and /wp-includes/ are configured for long-term caching. Some dynamic content can also be cached for a few minutes depending on the nature of such content. This drastically reduced the load on the backend.

For dynamic content, enabling Nginx FastCGI Caching also can improve response times. However, this requires careful tuning to avoid caching sensitive user-specific content. Moreover, there's no easy way to monitor and manage this cache centrally across all instances.

Finally, at the WordPress application level plugins like W3 Total Cache allow caching of pages, objects, and database queries. By integrating AWS ElastiCache for distributed caching, we ensure that cache data is shared across all instances, improving cache hit rates.

Securing the Entire Stack

Security and compliance are non-negotiable in enterprise environments. At every layer of the stack, we leverage AWS’s built-in capabilities to meet stringent compliance requirements.

Data encryption must be enabled both at rest (using AWS KMS for Aurora and EFS) and in transit (using HTTPS). All sensitive information, such as database credentials, is managed through AWS Secrets Manager, which centralizes secret storage and automates rotation.

To guard against web exploits, we deployed AWS WAF with managed rulesets tailored for WordPress, including protections against SQL injection, cross-site scripting, and bot traffic. For paths like /wp-admin/, we restricted access to specific IP addresses, ensuring only authorized personnel could access sensitive areas of the site.

Lastly, to secure the application from unauthorized access, we enforce a strict boundary between CloudFront and the ALB using pre-shared keys. This ensures that only traffic routed through CloudFront can reach the backend instances.

Conclusion

Building an enterprise-grade WordPress platform isn’t just about choosing the right AWS services—it’s about combining them in ways that solve real-world problems. Every decision we made, from using ECS Fargate to leveraging Aurora and EFS, was rooted in lessons learned from scaling WordPress in demanding environments.

If you’re looking to fast-track your deployment, we’ve developed a Terraform blueprint for WordPress on AWS ECS. It’s designed to help you hit the ground running while adhering to best practices we’ve honed over years of experience.

Let us know your thoughts or share your own experiences—together, we can make enterprise WordPress even better!