what are the advantages of aws cloud config over spring cloud config?

Based on what parameters can we decide on a config server? aws cloud config vs spring cloud config server?

1. if the application is developed based on Spring framework, which one will be a better option? aws-cloud-config / spring-config?
2. does both support XML/properties configuration other than YAML?
3. Can both be configured for High Availability?
4. Is it possible to define a workflow (for approval of changes that need to be moved to PRODUCTION, using jenkins for example?)

If your application is based on Spring, it makes sense to use Spring Cloud Config as you would be using a specific framework instead of a Generic framework like AWS config

yes, Spring Cloud Config supports both YAML and property files

Ultimately the Spring Cloud Config is a Spring Boot App, hence you can make it high available using the same strategy that we use for any Spring Application

The simplest Approval work flow would be

1. Configure your Jenkins Job to send mail for approval
2. Set-up Promotion using https://wiki.jenkins.io/display/JENKINS/Promoted+Builds+Plugin
3. Deploy the Artificats to the specific environment