Loki config common.storage.filesystem.(chunks|rules)_directory confusion

The docs state the common config key is for:

configuration to be shared between multiple modules. If a more specific configuration is given in other sections, the related configuration within this section will be ignored – Grafana Loki configuration parameters | Grafana Loki documentation.

Sounds fine. But common.storage.filesystem.chunks_directory and common.storage.filesystem.rules_directory are confusing because they don’t correspond to something “shared between multiply modules”. common.storage.filesystem.chunks_directory seems to be an alias for storage.filesystem.directory and common.storage.filesystem.rules_directory an alias for ruler.storage.local.directory (I tested this in a test container to figure it out). These are very specific to a given module. Seems really odd that these aliases are in common section, and with a different names to what they actually map to. Why are they in common? All it seems to achieve is confusing the user.

Common is useful when you have a block of configurations where most of them stay the same across multiple components, but one or two differs. I can’t find an example for Loki, but here is a good example for Mimir:

@tonyswumac Yeah I understand the concept of common configuration in general. My point was that in this case the config doesn’t seem to be common at all.