How to create an elasticbeanstalk environment through boto3 setting a keypair name - python-3.x

Question

If you uses the AWS console or even the command line, you won't get any issue in setting a default keypair to your Elasticbeanstalk environment.
But you do if using boto3.
Surprisingly, there's no any single mention about setting a keypair in the official boto3 documentation for elasticbeanstalk: https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/elasticbeanstalk.html.
Tried also to create a zip file containing the most basic files to make a simple website works. And supposedly, I can set a keypair name in the .elasticbeanstalk/config.yml". I did in this way:
branch-defaults:
default:
environment: app10-env
group_suffix: null
global:
application_name: app10
branch: null
default_ec2_keyname: main4
default_platform: PHP 7.4 running on 64bit Amazon Linux 2
default_region: us-east-1
include_git_submodules: true
instance_profile: null
platform_name: null
platform_version: null
profile: null
repository: null
sc: null
workspace_type: null
Yes, the "main4" exists in my AWS account. But creating an environment to my application with a zip containing it, it seems that it have no effect at all. After my environment has sucessfully deployed, I can check afterwards through console and see that have no keypair setted to environment. I need to go to a further step on console to set the keypair and await a new environment deployiment to perform the update.
Is there a real issue with the boto3 elasticbeanstalk when dealing with environment keypairs or I am doing something wrong?

Answer 1

I would set the OptionSettings when calling create_environment or include the keyname in the .ebextensions. Boto3 is not reading the EB CLI default config you are using i guess.
Refs
https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/elasticbeanstalk.html#ElasticBeanstalk.Client.create_environment
https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/environment-configuration-methods-before.html
Option to set
Namespace: aws:autoscaling:launchconfiguration
Option Names: IamInstanceProfile, EC2KeyName, InstanceType

Answer 2

The response of #f7o is not accurate, but helped to solve the problem.
There's no option for setting an keypair using "create_environment" command from boto3 client. Tried to use a "EC2KeyName", but it returned an exception of invalid value.
But using the "ebextensions" do the work. If someone else are interested in do the same task that I am, so everything that is needed to do is create a folder called ".ebextensions" with a file called "customkey.config" (the file name can be anything, but must be suffixed with .config), and with the following content:
option_settings:
- namespace: aws:autoscaling:launchconfiguration
option_name: EC2KeyName
value: <your_keypair_name>