AWS Elastic Beanstalk
Developer Guide (API Version 2010-12-01)
AWS services or capabilities described in AWS Documentation may vary by region/location. Click Getting Started with Amazon AWS to see specific differences applicable to the China (Beijing) Region.

Configuration

Event: You cannot configure an Elastic Beanstalk environment with values for both the Elastic Load Balancing Target option and Application Healthcheck URL option

The Target option in the aws:elb:healthcheck namespace is deprecated. Remove the Target option namespace) from your environment and try updating again.

Event: ELB cannot be attached to multiple subnets in the same AZ.

This message can be seen if you try to move a load balancer between subnets in the same Availability Zone. Changing subnets on the load balancer requires moving it out of the original availability zone(s) and then back into the original with the desired subnets. During the process, all of your instances will be migrated between AZs, causing significant downtime. Instead, consider creating a new environment and perform a CNAME swap.