NAS support

[willprice-oracle]

The README claims:

Compatible with Ecosystem: Storage backend support with Registry, OSS, NAS, Shared Disk, and P2P service. Compatible with the OCI images, and provide native eStargz images support.

But I can't find any documentation on what sort of network attached storage is supported. The configuration files indicates only local filesystems or block devices can be used, but is there existing support for using shared networked block volumes, NFS, or other similar technologies?

Many thanks

[imeoer]

It is better to mount NFS to the local directory and then configure nydus to use localfs as storage backend.

[willprice-oracle]

Hi @imeoer,
Thanks for the feedback.

Q1: Am I right in understanding that you're suggesting configuring the nydusd backend like so:

{
  "device": {
    "backend": {
      "type": "localfs",
      "config": {
        "dir": "/var/lib/nydus/blobs"
      }
    },
    "cache": {
      "type": "dummycache",
    }
  },
  "mode": "direct",
  "digest_validate": false,
  "iostats_files": false,
  "enable_xattr": false
}

Where I have /var/lib/nydus/blobs as an NFS mount?

Some notes on the configuration:

• I've disabled the blobcache, replacing it with the dummycache, since the hosts I have won't have any persistent local storage.
• I've disabled xattr since NFS doesn't support xattr.

Q2: If I assume my registry hosts are the only ones that are writing to the NFS share, am I correct in thinking that there won't be any trampling of state?

Q3: I'm assuming that I can't avoid the duplication of the nydus metadata files that the container hosts will download from the registry? In other words, there's not a way for me to store those metadata files on NFS too?

[imeoer]

A1: Right, the /var/lib/nydus/blobs directory should include all the blob files, for example, the sha256:xxx blob should name it xxx.
A2: What's means trampling of state? The opened blob files by nydusd should be readonly.
A3: Nydusd can mount a bootstrap (metadata) file from a local file, so we can also put it in a NAS mount directory.

[willprice-oracle]

Great, thanks again for your answers @imeoer . And for A2, yes, I did mean nydusd clients writing to the NFS store, it's good to have confirmation it uses it readonly.

[imeoer]

The files in device.backend.config.dir should be readonly, the cache dir (device.cache, but expect dummycache) should be writable.