Getting AWS credentials from keystore for discovery-ec2 plugin?

Elastic Stack Elasticsearch
11

The different keystore settings did affect the result, now able to create bucket. Here is keystore list output:
/mnt/elasticsearch# bin/elasticsearch-keystore list
discovery.ec2.access_key
discovery.ec2.secret_key
s3.client.default.access_key
s3.client.default.secret_key

Here is result of running shell script to create the repository bucket:
/mnt/elasticsearch# bin/s3-repo-create.sh es-lineartv_test
{"acknowledged":true}