Zonal shift in ARC

Amazon Application Recovery Controller (ARC) zonal shift allows you to shift traffic for a supported resource away from an impaired Availability Zone (AZ) in an AWS Region to healthy AZs in the same Region. Shifting your resource's traffic away from an impaired AZ reduces the duration and severity of impact caused by power outages, or hardware or software issues in an AZ, and helps to mitigate issues and quickly recover your application. You might choose to shift traffic, for example, because a bad deployment is causing latency issues, or because the Availability Zone is impaired.

Some AWS resources require that you opt-in to use zonal shift, and some resources are automatically enabled. For more information, refer to Supported resources.

Before you start a zonal shift, you must prescale your application and ensure that you have sufficient capacity to shift traffic away from an Availability Zone. After prescaling, you can choose the Availability Zone to shift away from and the resource to shift traffic away for, and then start the zonal shift. You can cancel the shift at any time to have traffic begin returning to the original Availability Zone. For more information, see Best practices for zonal shifts in ARC

All zonal shifts are temporary mitigations. You set an initial expiration when you start a zonal shift, from one hour up to three days (72 hours), which you can extend, if you need to continue the traffic shift.

In specific scenarios, zonal shift does not shift traffic away from the AZ. For more information, see Supported resources.