---
title: Charmhub | filesystem_info interface
description: Interfaces describe the relation between two charms. This interface shows
  opinionated, standardized interface specifications for charm relations.
url: https://charmhub.io/integrations/filesystem_info
---

# 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]](https://github.com/canonical/charmlibs/blob/main/interfaces/filesystem_info/interface/vv0/schema.py)

### Example

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

## Charms implementing this interface

### Providers

* [nfs-server-proxy](https://charmhub.io/nfs-server-proxy)
* [cephfs-server-proxy](https://charmhub.io/cephfs-server-proxy)

### Requirers

* [filesystem-client](https://charmhub.io/filesystem-client)

## Other charms using this interface

### Providers

### Requirers