Resources and scenarios supported for zonal shift and zonal autoshift - Amazon Application Recovery Controller (ARC)

Resources and scenarios supported for zonal shift and zonal autoshift

Amazon Application Recovery Controller (ARC) currently supports the following resources for zonal shift and zonal autoshift:

  • Network Load Balancers with cross-zone load balancing disabled

  • Application Load Balancers with cross-zone load balancing disabled

Load balancing resources that are supported are automatically registered with ARC so you can use them with zonal shift (and zonal autoshift). You can start a zonal shift for a load balancer in the Elastic Load Balancing console (in most AWS Regions) or in ARC.

Review the following conditions for working with zonal shifts, zonal autoshift, and resources in ARC:

  • Zonal shift and zonal autoshift aren't supported with cross-zone load balancing. For a load balancer to be registered with ARC, make sure that you've disabled or turned off cross-zone load balancing for the load balancer in Elastic Load Balancing.

  • In specific scenarios, zonal shift does not shift traffic away from the Availability Zone. If the load balancer target groups in the AZs in a Region don't have any instances, or if all of the instances are unhealthy, then the load balancer is in a fail open state. If you start a zonal shift for a load balancer in this scenario, the zonal shift does not change which AZs the load balancer uses because the load balancer is already in a fail open state. This is expected behavior. Zonal shift cannot force one AZ to be unhealthy and shift traffic to the other AZs in a Region if all AZs are failing open (unhealthy).

  • Both public and internal (private) Network Load Balancers and Application Load Balancers are supported.

  • A resource must be active and fully provisioned to shift traffic for it. Before you start a zonal shift for a resource, check to make sure that it's a managed resource in ARC. For example, view the list of managed resources in the AWS Management Console, or use the get-managed-resource operation with the resource's identifier.

  • When an Application Load Balancer is the target of a Network Load Balancer, start the zonal shift from the Network Load Balancer. If you start the zonal shift from the Application Load Balancer, the Network Load Balancer doesn't stop sending traffic to the Application Load Balancer and its targets.

  • The resource for a zonal shift must be a managed resource that has been registered with ARC by an AWS service. Elastic Load Balancing automatically registers with ARC all Network Load Balancers and Application Load Balancers that have cross-zone load balancing turned off.

  • To start a zonal shift with a resource, it must be deployed in the Availability Zone and AWS Region where you start the shift. Make sure that you start a zonal shift in the same Region that the AZ you want to shift away from is in, and that the resource that you're shifting traffic for is in the same AZ and Region as well.

  • Make sure that you have the correct IAM permissions to use zonal shift with a resource. For more information, see IAM and permissions for zonal shift.