Hands-On Microservices with Kubernetes

Environment variables

Environment variables are another favorite. They are useful when your program runs in an environment that may be set up by another program (or a shell script). Environment variables are typically inherited from the parent environment. They are also used for running interactive programs when the user always wants to provide the same option (or set of options) to the program. Instead of typing a long command line with the same options again and again, it is much more convenient to set an environment variable once (maybe even in your profile) and just run the program with no arguments. A good example is the AWS CLI, which allows you to specify many configuration options as environment variables (for example, AWS_DEFAULT_REGION ...