/opt/appdata. Under this tree, you can create a single configuration directory for each of your containers.
-vflag, which will tell Docker to overlay your host directory over the container's directory:
-vhas mapped the host machine's
/opt/appdata/my_configdirectory over the container's internal
/configdirectory as this contains pertinent runtime configuration for the underlying application. For applications that require further data, such as media, our documentation will clearly indicate which internal directories need mapping.