What's new at AWS 📢

❎ AWS NLB supports Amazon Application Recovery Controller’s zonal shift and zonal auto-shift features on load balancers that are enabled across zones.

❎ This zonal shift allows customer to quickly shift traffic away from an impaired Availability Zone and recover from events such as bad application deployment and gray failures.

❎ This zonal auto-shift helps to automatically shifts traffic away from an Availability Zone, when AWS identifies potential impact to it.

❎ With this feature, customers can shift traffic away from an AZ in the event of a failure to other AZs.

❎ What is cross-zone on NLBs:
🔻 It is a popular configuration for customers that require an even distribution of traffic across application targets in multiple AZs.

❎ How this feature is work:
🔻 When zonal shift or auto-shift is triggered, automatically the NLB will block all traffic to targets in the AZ that is impacted.

❎ How to configure this feature
Step 1️⃣ : Enable configuration to allow zonal shift to act on your load balancer(s) using the NLB console or API
Step 2️⃣ : Trigger zonal shift or enable zonal auto-shift for the chosen NLBs via Amazon Application Recovery Controller console or API.

🥁 Important key note:
🔻 AWS ALB is enabled with cross-zone load balancing by default.
🔻 AWS NLB is disabled with cross-zone load balancing by default.
🔻 Its recommended to disable cross-zone load balancing for zonal shift feature to properly work in Load balancer level.

📌 Explore more about NLB zonal shift:
https://docs.aws.amazon.com/elasticloadbalancing/latest/network/zonal-shift.html

📌 Detailed steps to configure Load balancer's for zonal shift:
https://aws.amazon.com/blogs/aws/zonal-autoshift-automatically-shift-your-traffic-away-from-availability-zones-when-we-detect-potential-issues/