filesystem_info

Usage

This interface defines how a charm that exports a shared filesystem can expose the required mount information to a client charm that wants to mount the filesystem.

Direction

The filesystem_info interface implements a provider/requirer pattern. The Requirer is a charm that wishes to mount a shared filesystem, and the Provider is the charm exporting the mount information to do that.

flowchart TD
  Requirer --> Provider
  Provider -- endpoint --> Requirer

Behavior

The exported endpoint from the Provider needs to adhere to a sublanguage of the URI grammar, which is specified by [RFC 3986](https://datatracker.ietf.org/doc/html/rfc3986

Examples

The following examples show some URIs adhering to the defined grammar, and their equivalent components.

nfs://(192.168.1.1:65535)/export
- scheme: nfs
- userinfo: None
- hosts: 192.168.1.1:65535
- path-absolute: /export
- options: None

lustre://(192.168.227.11%40tcp1,192.168.227.12%40tcp1)/export
- scheme: lustre
- userinfo: None
- hosts: 192.168.227.11@tcp1 192.168.227.12@tcp1
- path-absolute: /export
- options: None

cephfs://fsuser@(192.168.1.1,192.168.1.2,192.168.1.3)/export?fsid=asdf1234&auth=secret%3AYXNkZnF3ZXJhc2RmcXdlcmFzZGZxd2Vy&filesystem=scratch
- scheme: cephfs
- userinfo: fsuser
- hosts: 192.168.1.1 192.168.1.2 192.168.1.3
- path-absolute: /export
- options:
  - fsid: asdf1234
  - auth: secret:YXNkZnF3ZXJhc2RmcXdlcmFzZGZxd2Vy
  - filesystem: scratch

Provider

Is expected to adhere to both the defined grammar and the additional requirements specified here.
Is expected to export mount information for a valid and accessible shared filesystem.

Requirer

Is expected to be able to parse the exported endpoint from the provider according to the defined grammar.
Is expected to either have support for mounting the provider's exported filesystem, or gracefully handle when it cannot mount it.

Relation Data

Only the provider must export relation data.

[Pydantic Schema]

Example

provider:
  app: {
    "endpoint": "lustre://(192.168.227.11%40tcp1,192.168.227.12%40tcp1)/export"
  }
  unit: {}
requirer:
  app: {}
  unit: {}