CSI plugin for NFS []

Description

CSI-NFS is a Container Storage Interface (CSI) plugin that provides network filesystem (NFS) support.

This project may be compiled as a stand-alone binary using Golang that, when run, provides a valid CSI endpoint. This project can also be vendored or built as a Golang plugin in order to extend the functionality of other programs.

Runtime Dependencies

The node portion of the plugin can be run on any Linux node that is able to mount NFS volumes. The Node service verifies this by checking for the existence of /sbin/mount.nfs and /sbin/mount.nfs4 during a NodeProbe.

Installation

CSI-NFS can be installed with Go and the following command:

$ go get github.com/thecodeteam/csi-nfs

The resulting binary will be installed to $GOPATH/bin/csi-nfs.

If you want to build csi-nfs with accurate version information, you'll need to run the go generate command and build again:

$ go get github.com/thecodeteam/csi-nfs
$ cd $GOPATH/src/github.com/thecodeteam/csi-nfs
$ go generate && go install

The binary will once again be installed to $GOPATH/bin/csi-nfs.

Start plugin

Before starting the plugin please set the environment variable CSI_ENDPOINT to a valid Go network address such as csi.sock:

$ CSI_ENDPOINT=csi.sock csi-nfs
INFO[0000] configured com.thecodeteam.csi-nfs            privatedir=/dev/csi-nfs-mounts
INFO[0000] identity service registered
INFO[0000] controller service registered
INFO[0000] node service registered
INFO[0000] serving                                       endpoint="unix:///csi.sock"

The server can be shutdown by using Ctrl-C or sending the process any of the standard exit signals.

Using plugin

The CSI specification uses the gRPC protocol for plug-in communication. The easiest way to interact with a CSI plugin is via the Container Storage Client (csc) program provided via the GoCSI project:

$ go get github.com/thecodeteam/gocsi
$ go install github.com/thecodeteam/gocsi/csc

Then, have csc use the same CSI_ENDPOINT, and you can issue commands to the plugin. Some examples...

Get the plugin's supported versions and plugin info:

$ csc -e csi.sock identity supported-versions
0.1.0
$ csc -e csi.sock -v 0.1.0 identity plugin-info
"com.thecodeteam.csi-nfs"	"0.1.0+9"
"commit"="8b9c33929bc954614f84d687b47dae71891d5514"
"formed"="Tue, 13 Feb 2018 17:37:15 UTC"
"semver"="0.1.0+9"
"url"="https://github.com/thecodeteam/csi-nfs"

Publish an NFS volume to a target path:

$ csc -e csi.sock -v 0.1.0 n publish --cap SINGLE_NODE_WRITER,mount,nfs --target-path /tmp/mnt 192.168.75.2:/data
192.168.75.2:/data

Unpublish NFS volume:

$ csc -e csi.sock -v 0.1.0 n unpublish --target-path /tmp/mnt 192.168.75.2:/data
192.168.75.2:/data

Parameters

No additional parameters are currently supported/required by the plugin

Configuration

The CSI-NFS plugin is built using the GoCSI package. Please see its configuration section for a complete list of the environment variables that may be used to configure this plugin

The following table is a list of this SP's default configuration values:

Name	Value
X_CSI_SPEC_REQ_VALIDATION	true
X_CSI_SERIAL_VOL_ACCESS	true
X_CSI_SUPPORTED_VERSIONS	0.1.0
X_CSI_PRIVATE_MOUNT_DIR	/dev/disk/csi-nfs-private

Capable operational modes

The CSI spec defines a set of AccessModes that a volume can have. CSI-NFS supports the following modes for volumes :

// Can only be published once as read/write on a single node,
// at any given time.
SINGLE_NODE_WRITER = 1;

// Can only be published once as readonly on a single node,
// at any given time.
SINGLE_NODE_READER_ONLY = 2;

// Can be published as readonly at multiple nodes simultaneously.
MULTI_NODE_READER_ONLY = 3;

// Can be published at multiple nodes simultaneously. Only one of
// the node can be used as read/write. The rest will be readonly.
MULTI_NODE_SINGLE_WRITER = 4;

// Can be published as read/write at multiple nodes
// simultaneously.
MULTI_NODE_MULTI_WRITER = 5;

The plugin attempts no verification that NFS clients and servers are configured correctly for multi-node writer scenarios (e.g. running rpc.lockd for NFSv3)

Support

For any questions or concerns please file an issue with the csi-nfs project or join the Slack channel #project-rexray at codecommunity.slack.com.