Deselect ‘Custom Availability Zones’ in Elastic Beanstalk

It is frustrated that Elastic Beanstalk console does not allow you deselect the custom availability zone once you selected and applied . I guess AWS just missed that function in the javascript.

Here is a example. There is no way for me to deselect ap-southeast-2a in the custom availability zone in the Elastic Beanstalk console.

The solution is to save the current configuration -> download the configuration file from S3 -> modify it -> upload to the original bucket with the same name -> load configuration.

By default, Elastic Beanstalk saves the environment configuration to the bucket elasticbeanstalk–/resources/templates//. Just go to that bucket to download the configuration file and modify it to fit your needs. Then upload it back and load the modified configuration. 

Here is the modification I made. It takes about 2 minutes to apply, and no outage was required.

Before
aws:autoscaling:asg:
Availability Zones: Any 1
MinSize: '1'
MaxSize: '1'
Custom Availability Zones: ap-southeast-2a
After
aws:autoscaling:asg:
Availability Zones: Any
MinSize: '1'
MaxSize: '1'