Application configuration of a complex enterprise system
I highly recommend Consul for configuration management as it is a high reliability, distributed system that provides quite a few and easy to use features with a simple Rest API. Also the community edition is free :), although for a large enterprises there is an enterprise offering.

I am a particular fan of the Key Value store, because it allows me to have separate configurations for my micro-services and back-end services (written in C#/.Net Core and Java respectively) in all three environments (Dev, Beta, Prod). 

Whenever I add a new service or application, the configuration for each environment is added to the Key Value store and a simple config client downloads the configuration during the application's bootstrap/loading routines.

You can read a bit more here but in a nutshell:


  Consul has multiple components, but as a whole, it is a tool for
  discovering and configuring services in your infrastructure. It
  provides several key features:
  
  Service Discovery: Clients of Consul can provide a service, such as
  api or mysql, and other clients can use Consul to discover providers
  of a given service. Using either DNS or HTTP, applications can easily
  find the services they depend upon.
  
  Health Checking: Consul clients can provide any number of health
  checks, either associated with a given service ("is the webserver
  returning 200 OK"), or with the local node ("is memory utilization
  below 90%"). This information can be used by an operator to monitor
  cluster health, and it is used by the service discovery components to
  route traffic away from unhealthy hosts.
  
  KV Store: Applications can make use of Consul's hierarchical key/value
  store for any number of purposes, including dynamic configuration,
  feature flagging, coordination, leader election, and more. The simple
  HTTP API makes it easy to use.
  
  Multi Datacenter: Consul supports multiple datacenters out of the box.
  This means users of Consul do not have to worry about building
  additional layers of abstraction to grow to multiple regions.
  
  Consul is designed to be friendly to both the DevOps community and
  application developers, making it perfect for modern, elastic
  infrastructures.