Acquia Cloud Architecture and Key Concepts

This section of the Acquia Cloud documentation describes how Acquia Cloud works, including information about Acquia Cloud architecture, security, high availability features, and compliance with standards and regulations.

Acquia Cloud provides a robust managed solution for mission-critical Drupal applications. Traditional hosting services may provide little more than virtual machines, leaving you with the task of managing and running the servers. With Acquia Cloud, you bring your code and files, and Acquia handles the rest. Acquia takes care of selecting, deploying, and maintaining a Drupal-optimized platform. Acquia Cloud provides high availability elastic cloud resources, with configuration management, monitoring, optimization, and caching built in, all backed up by an operations team staffed by Drupal experts, ready to respond 24 hours a day, seven days a week (24/7).

Acquia Cloud infrastructure

Acquia Cloud sites run on a Drupal-optimized platform hosted in the Amazon Web Services (AWS) cloud environment. The core of the platform is an open-source LAMP server stack, combining the Linux (Ubuntu) operating system, Apache web server, MySQL (Percona) database, and PHP programming language with Drupal. Acquia Cloud servers are built on the AWS Elastic Compute Cloud (EC2), Elastic Block Storage (EBS), and Elastic IPs (EIP).

The exact configuration of an Acquia Cloud server depends on several factors, including whether the site is part of Acquia Cloud Enterprise or Acquia Cloud Professional. Here is an example of a large Acquia Cloud Enterprise site:

Cloud architecture

Key

A — Using a CDN is optional for distribution of content and support files (like images, CSS, JS) to the network edge.
B — Acquia Cloud uses a software load balancer (nginx) and a reverse proxy cache (Varnish), in an active-passive configuration, fronted by Amazon's Elastic IP service.
C — Web tier consists of n Apache servers, load balanced in round-robin, running PHP with OPCache and memcache.
D — Acquia Cloud uses bi-directional replication between database pairs, allowing seamless failover and high availability. The failover mechanism is Drupal-specific, rather than MySQL cluster.
E — Acquia Cloud uses the Gluster cluster file system to make files available to all web nodes, and ensure durability and availability of data.
F — Acquia Cloud distributes application code to web nodes using the version control system (Git or SVN).
LB — load balancer (nginx)
FS — file system (Gluster)

As shown in the diagram, there are four main components to an Acquia Cloud site:

  • Reverse proxy caching and load balancing servers (Varnish/nginx)
  • Web servers (Apache with PHP and Drupal code)
  • Database servers (MySQL (Percona))
  • Network file system (GlusterFS)

For more information, see Acquia Cloud technology platform and supported software.

Compared to Acquia Cloud Professional, Acquia Cloud Enterprise offers additional features for high availability, including redundant server instances at each level of the stack, and higher levels of support, including unlimited application support and an operations team available 24x7 to remotely administer your applications and to change your infrastructure on demand. For more information, see Comparing Acquia Cloud Professional and Acquia Cloud Enterprise.

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