New – AWS Global Accelerator for Availability and Performance

Having previously worked in an area where regulation required us to segregate user data by geography and abide by data sovereignty laws, I can attest to the complexity of running global workloads that need infrastructure deployed in multiple countries. Availability, performance, and failover all become a yak shave as you expand past your original data center. Customers have told us that they need to run in multiple regions, whether it is for availability, performance or regulation. They love that they can template their workloads through AWS CloudFormation, replicate their databases with Amazon DynamoDB Global Tables and deploy serverless workloads with AWS SAM. All of these capabilities can be executed in minutes and provide a global experience for your audience. Customers have also told us that they love the regional isolation that AWS provides to reduce blast radius and increase availability, but they would like some help with stitching together other parts of their applications.

Introducing AWS Global Accelerator

That’s why I am pleased to announce AWS Global Accelerator, a network service that enables organizations to seamlessly route traffic to multiple regions and improve availability and performance for their end users. AWS Global Accelerator uses AWS’s vast, highly available and congestion-free global network to direct internet traffic from your users to your applications running in AWS regions. With AWS Global Accelerator, your users are directed to your workload based on their geographic location, application health, and weights that you can configure. AWS Global Accelerator also allocates static Anycast IP addresses that are globally unique for your application and do not change, thus removing the need to update clients as your application scales. You can get started by provisioning your Accelerator and associating it with your applications running on: Network Load Balancers, Application Load Balancers, or Elastic IP addresses. AWS Global Accelerator then allocates two static Anycast IP addresses from the AWS network which serve as an entry point for your workloads. AWS Global Accelerator supports both TCP and UDP protocols, health checking of your target endpoints and will route traffic away from unhealthy applications. You can use an Accelerator in one or more AWS regions, providing increased availability and performance for your end users. Low-latency applications typically used by media, financial, and gaming organizations will benefit from Accelerator’s use of the AWS global network and optimizations between users and the edge network.

Image 1 – How it Works

Here’s what you need to know:

Static Anycast IPs – Global Accelerator uses Static IP addresses that serve as a fixed entry point to your applications hosted in any number of AWS Regions. These IP addresses are Anycast from AWS edge locations, meaning that these IP addresses are announced from multiple AWS edge locations, enabling traffic to ingress onto the AWS global network as close to your users as possible. You can associate these addresses to regional AWS resources or endpoints, such as Network Load Balancers, Application Load Balancers, and Elastic IP addresses. You don’t need to make any client-facing changes or update DNS records as you modify or replace endpoints. An Accelerator’s IP addresses are static and will serve as the front door for your user-facing applications.

AWS’s Global Network – Traffic routed through Accelerator traverses the well monitored, congestion free, redundant AWS global network (instead of the public internet). Clients route to the optimal region based on client location, health-checks, and configured weights. Traffic will enter through an AWS edge location that is advertising an Accelerator’s Anycast IP addresses, from where the request will be routed through an optimized path towards the application.

Client State – AWS Global Accelerator enables you to build applications that keep state as an essential requirement. Stateful applications route users to the same endpoint, after their initial connection. Global Accelerator achieves this through setting the SourceIP of the client requester as the identifier for maintaining state, irrespective of the port and protocol.

AWS Global Accelerator in Action

To get familiar with AWS Global Accelerator’s features I am going to use two EC2 hosted WordPress deployments that are behind an Application Load Balancer. To test the global nature of AWS Global Accelerator, I have deployed our application to Singapore and Tokyo regions. Image 3 illustrates our happy path. Traffic is sent from our client to the nearest edge location via the two Anycast IP address that the edge location is advertising. Our request routes through the AWS global network to the Accelerator which selects the closest healthy endpoint group. An Application Load Balancer terminates our request and passes it to the WordPress instance where our content is served from.

Image 2 – User Flow

I’ve created two content servers using the instructions found here. I have changed the home banners for the regions we will be serving our content from so that I can identify which path I am routed through. With our content servers created we build an Application Load Balancer for each and wait for them to become healthy and in-service.

Image 3 – Shaun’s Global Website

Creating the Global Accelerator is as simple as choosing a name, specifying the listener type (port 80 and TCP for WordPress) and creating some endpoint groups for each region. Let’s configure a listener for our Accelerator that clients connect to once onboard the edge network. As we are serving HTTP traffic, port 80 is a natural choice. I have enabled client affinity using SourceIP which redirects our test clients to the same region and application once they have connected for the first time.

Endpoint groups are targets for our Accelerator, by default each group has a traffic dial of 100. Turning down the traffic dial allows redirection of clients to other endpoint groups or another AWS region, handy for performing maintenance or dealing with an unexpected traffic surge. For our experiment, I choose the Tokyo and Singapore region with the default dial of 100.

Image 4 – Configuring endpoint groups

Health checks are a powerful tool that can be used either in a simple configuration or provide deep application awareness. Today I am serving a simple website using the default HTTP health check, polling for a 200 OK HTTP on the default path. To complete our configuration we need to populate our endpoint groups with the Application Load Balancers we created earlier.

Image 5 – Adding our ALB’s to an Endpoint Group

With everything configured we can start routing traffic through our two Anycast IP addresses assigned by the Accelerator. This can be done with your browser, an HTTP client or curl. As I want to test a global audience, I will use a proxy to set my location through various locations across Asia, America, and Europe to see how our traffic is routed.

Image 6 – Requests being distributed to our global website.

One of the most powerful features of AWS Global Accelerator is the ability to fail between regions in less than a minute. I’ve set up a load test to hit the site with 100 requests per second and will turn off the Singapore server to test how fast our traffic is routed through to our Tokyo endpoint.

Traffic starts routing through our Accelerator at 03:15, at 3:30 I shut down the Singapore instance. At 3:31 Tokyo has already processed close to 4,000 requests and is serving all the traffic. At 3:35 I enable the Singapore server. Because of the health check warm up (90 seconds), we don’t start seeing recovery until 3:38. If I had configured a more aggressive health check we would fail and recover within five minutes!

Availability and Pricing

In AWS Global Accelerator, you are charged for each accelerator that is provisioned and the amount of traffic in the dominant direction that flows through the accelerator. An accelerator is the resource you create to direct traffic to optimal endpoints over the AWS global network. Customers will typically set up one accelerator for each application, but more complex applications may require more than one accelerator. For every accelerator that is provisioned (both enabled and disabled), you are charged a fixed hourly fee and an incremental charge over your standard Data Transfer rates, also called a Data Transfer-Premium fee (DT-Premium). DT-Premium is calculated every hour on the dominant direction of your traffic, i.e. inbound traffic to your application or outbound traffic from your application to your users on the internet.

Fixed fee: For every full or partial hour when an accelerator runs in your account, you are charged $0.025 until it is deleted.
Data Transfer-Premium fee (DT-Premium): This is a rate per gigabyte of data transferred over the AWS network. The DT-Premium rate depends on the AWS Region (source) that serves the request and the AWS edge location (destination) where the responses are directed. You will only be charged DT-Premium in the dominant data transfer direction.

AWS Global Accelerator is available in US East (N. Virginia), US East (Ohio), US West (Oregon), US West (N. California), Europe (Ireland), Europe (Frankfurt), Asia Pacific (Tokyo) and Asia Pacific (Singapore).