overlay.md

Overlay Mount

The Overlay Mount object provides a way, using OverlayFS, to present a read-only mount as a read-write mount. This is useful in several differnt image schemes.

The Overlay Mount object supports layered mounts. This is handled by providing multiple mount descriptors to the lower: [] section.

Overlay Mounts are always read-write.

Example Overlay Mount specification:

{
    "kind": "overlay",
    "overlay": {
      "lower": [
        {
            // Mount specification
            // ...
        }
      ]
    }
}

The following examples give complete usage cases for Overlay Mounts:

• ../examples/nfs-scheme
• ../examples/nfs-loopback-scheme
• ../examples/rbd-scheme
• ../examples/iscsi-scheme