Configuring the Amazon Application Recovery Controller (ARC) zonal autoshift observer notifications is essential for building resilient workloads on AWS, aligning with the reliability pillar of the AWS Well-Architected Framework. AWS offers a variety of design principles and services to assist users in creating highly available and fault-tolerant architectures. A critical aspect of a robust resilience strategy is ensuring that workloads can endure potential Availability Zone (AZ) disruptions within an AWS Region.
In this article, we will explore how to leverage ARC zonal autoshift observer notifications as a proactive measure against potential AZ issues. By implementing these notifications, you can actively monitor your application’s health and take necessary actions to ensure service continuity. Let’s learn how to enable these notifications in your operational regions and receive alerts through your preferred communication channels.
Zonal Autoshift Observer Notifications
ARC facilitates rapid recovery of workloads with two primary functionalities: multi-AZ recovery, which encompasses zonal shift and zonal autoshift, and multi-Region recovery, which includes routing control and readiness checks.
Zonal autoshift enables AWS to automatically redirect traffic away from an AZ upon detecting a potential failure. This operates on the principle of static stability, where your application is pre-scaled across multiple AZs to handle a complete loss of capacity in any single zone. For more insights into static stability and how Amazon designs its services for this purpose, refer to the Amazon Builders’ Library post on static stability using Availability Zones.
If you haven’t yet configured zonal autoshift for your resources but want to be informed when a shift occurs, ARC now offers observer notifications. These notifications, delivered via Amazon EventBridge events, alert you when AWS is shifting other users away from an AZ (see example zonal autoshift events). Consequently, observer notifications can serve as an indicator for users to verify that their critical workloads are functioning properly or if they need to initiate recovery actions.
Operational Use of Zonal Autoshift Observer Notifications
Timely alerts regarding potential AZ impairments are vital for maintaining application availability and resilience. These notifications act as an early warning system, enabling you to monitor the health of your applications proactively and make informed decisions to mitigate the impacts of an AZ issue. Being notified when AWS initiates an autoshift allows for swift assessment of the situation, coordination of incident response efforts, and execution of necessary recovery procedures to ensure service continuity.
For all workloads, we advocate for integrating with the ARC zonal autoshift functionality so that AWS can automatically reroute traffic from affected AZs. For a deeper exploration of zonal autoshift, refer to the detailed post, “Zonal Autoshift – Automatically Shift Your Traffic Away from Availability Zones When We Detect Potential Issues.” We recognize that adopting this feature may be a gradual process for some teams; therefore, we recommend enabling zonal autoshift observer notifications at a minimum to receive direct signals from AWS regarding potential AZ issues.
We suggest integrating these notifications into your standard operational incident response protocols. If you lack established processes for managing operational incidents, consider reviewing the “Responding to Events” section of the Operational Excellence Pillar – AWS Well-Architected. For instance, observer notifications can trigger alerts to the relevant on-call teams responsible for your AWS workloads. Subsequently, operators can assess their applications’ health and determine which operational runbooks to activate.
Ultimately, the aim is to automate responses to these events. This could involve enabling zonal autoshift at the workload level for automatic traffic redirection or having the observer notification activate custom runbooks that initiate AZ evacuation processes.
Walkthrough: Activating Zonal Autoshift Observer Notifications
Now that we understand the advantages and applications of zonal autoshift observer notifications, let’s walk through the steps to enable this feature and start receiving alerts.
- Create an Amazon SNS Topic for Notifications
We utilize Amazon Simple Notification Service (SNS) to send email notifications to subscribers when an observer notification event is triggered. To create an Amazon SNS topic, follow the guidelines in the documentation on creating an Amazon SNS topic, ensuring you select the Standard topic type.
Subscribe your email address to the newly created topic. For further details, check out the section on subscribing an email address to an Amazon SNS topic using the AWS Management Console. Confirm the email subscription by clicking “Confirm subscription” in the email from Amazon SNS. - Enable ARC Zonal Autoshift Observer Notifications
Activate the zonal autoshift observer notifications in the Console:
– Open the ARC console.
– In the navigation pane, under Multi-AZ, select Zonal autoshift.
– Click on “Set up zonal autoshift observer notification.”
– Choose “Enable autoshift observer notification.”
– Enter a name for the EventBridge rule.
– Select the EventBridge default bus in your region, for example,arn:aws:events:eu-west-1:123456789012:event-bus/default.
– Choose the Amazon SNS topic you created earlier.
– Click “Complete.”
You will now have an EventBridge rule configured to match observer notification events and deliver them through Amazon SNS to your email.
Solution Overview
Observer notifications are relevant to all users within the Region, meaning you only need to set up delivery in one AWS account. However, you must enable zonal autoshift observer notifications in each AWS Region where you wish to receive alerts. This can be accomplished manually by repeating the previous steps in each AWS Region or through AWS CloudFormation StackSets to automate the process.
This solution employs two CloudFormation templates. The first template creates a CloudFormation stack with IAM resources, roles, and policies for EventBridge and CloudFormation StackSets utilized in the second template. The second template creates a CloudFormation StackSet where you specify the Regions for monitoring. Each StackSet in the selected AWS Regions enables zonal autoshift notifications and sets up an EventBridge rule to forward those events to your hub Region.
For additional insights on operational excellence, consider visiting Training Industry, which provides excellent resources on this topic.
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