Scaled-out application components should use a centrally stored configuration to provide a unified behavior that can be adjusted simultaneously.
|How can the configuration of scaled out application component instances be controlled in a coordinated fashion?|
Application components of a Distributed Application often have configuration parameters. Storing configuration information together with the application component implementation can be unpractical as it results in more overhead in case of configuration changes. Each running instance of the application component must be updated separately. Component images stored in Elastic Infrastructures or Elastic Platforms also have to be updated upon configuration change.
Configurations are stored in a central Storage Offering, commonly, a Relational Database, Key-Value Storage, or Blob Storage from where it is accessed by all running component instances either by accessing the storage periodically or by sending messages to the components.
Blob Storage, Relational Database, Key-Value Storage, Message-oriented Middleware, Provider Adapter, Elasticity Manager, Elastic Load Balancer, Elastic Queue, Watchdog