Add mount-point type

[dplore]

Change Scope

• Add filesystem type as /system/mount-points/mount-point/type
• This change is backwards compatible
• The operational use case is to give a human a hint as to the type of storage device in use for troubleshooting and diagnostics purposes. Example storage types might include flash, HDD, temporary/ramdisk or network based.

Platform Implementations

• Cisco show filesystem contains a type field
• JunOS show-system-storage has a filesystem field that is suitable for communicating type.

[OpenConfigBot]

No major YANG version changes in commit 57db022

[earies]

Regarding mount-points (and a few other items that happen to be modeled under /system today), I'd be curious to get your thoughts of a few things since this is being touched. First I'll place the contents of this subtree including this patch here to illustrate:

module: openconfig-system
  +--rw system
     +--ro mount-points
        +--ro mount-point* [name]
           +--ro name     -> ../state/name
           +--ro state
              +--ro name?                string
              +--ro storage-component?   -> /oc-platform:components/component/name
              +--ro size?                uint64
              +--ro available?           uint64
              +--ro utilized?            uint64
              +--ro type?                string

Now, the first is anything under /system related to resources has primarily been designed to assume the active CONTROLLER_CARD... more of an assumption. In this case there is at least a child leaf that is a leafref to a component however our list key here is a string name. Assume you want to convey both primary/secondary controller cards, one has to come up w/ a unique naming scheme now (or if you can convey this information from other components of the distributed system). A proper naming scheme to account for uniqueness would be to encode the component name thus likely duplicating what the leafref is also doing.

For storage mount-points in general, I think it would be helpful to map each leaf value/description to something like the output of the df command. In some cases this is self explanatory, in others not as much. For this patch, I'll assume that the type maps to what is under the Filesystem column whereas the key name is associated to Mounted on - would you agree?

But overall, I'm of the opinion we consider the possible relocation of this hierarchy to /components/component/storage as it can be unique to each component and categorized as such vs. attempting the inverse.

The same holds true for CPU, memory, processes, utilization (some of which has some level of duplication already)

[dplore]

Yes, the type maps to linux df's "Filesystem" column and the key name maps to df's "Mounted on"

/system is indeed meant to represent to global state of the device. It seems no notion of redundant controller cards was ever explicitly factored into it's creation. To date we've expected the primary controller card's state to be transparently reflected as part of /system. So a management system does not need to know there are redundant cards when looking at this tree. So /system/mount-points is expected to reflect the PRIMARY CONTROLLER_CARD values.

It does seem more complete to also have a way to inspect the properties of the SECONDARY CONTROLLER_CARD in general. So far I we haven't had this use case. This could be evaluated in a separate pull request

[s19nal]

as reviewed on OC operators meeting - this looks good to me