How can configuration data be passed to containers?

Configuration data can be passed to containers mainly using environment variables and mounted volumes, making this the correct choice.

Environment variables allow you to provide specific configuration settings to your application at runtime without needing to recompile the container image. This is particularly useful for parameters that may change across environments, such as database connection strings or API keys.

Mounted volumes enable you to provide a more extensive configuration dataset in the form of files or directories that can be shared between the host and the container. This allows you to manage configurations externally and modify them without altering the container’s filesystem or redeploying the image.

These methods are preferred due to their flexibility and the decoupling of configuration data from application code, making updates easier and enabling better practices in application deployment and management. This is especially important in dynamic environments, like Kubernetes, where containers may be frequently created and destroyed.

In contrast, passing configuration data through separate cluster nodes or via network requests is not a standard method for direct configuration input. Modifying the container image would require rebuilding the image, which goes against the principles of immutable infrastructure and can complicate version control and deployment processes.