CSI Driver for VxFlex OS

Description

CSI Driver for VxFlex OS is a Container Storage Interface (CSI) driver that provides VxFlex OS support. It supports CSI specification version 1.1.

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 built as a Golang plug-in in order to extend the functionality of other programs.

Building

This project is a Go module (see golang.org Module information for explanation). The dependencies for this project are in the go.mod file.

To build the source, execute make clean build.

To run unit tests, execute make unit-test.

To build a docker image, execute make docker.

You can run an integration test on a Linux system by populating the file env.sh with values for your VxFlex OS system and then run "make integration-test".

Runtime Dependencies

The Node portion of the driver can be run on any node that is configured as a VxFlex OS SDC. This means that the scini kernel module must be loaded. Also, if the X_CSI_VXFLEXOS_SDCGUID environment variable is not set, the driver will try to query the SDC GUID by executing the binary /opt/emc/scaleio/sdc/bin/drv_cfg. If that binary is not present, the Node Service cannot be run.

Installation

Installation in Kubernetes should be done using the install.vxflexos script and accompanying Helm chart in the helm directory. For more information, please refer to the CSI Driver for VxFlex OS Product Guide and CSI Driver for VxFlex OS Release Notes. The driver will be started in Kubernetes as a result of executing the installation script.

Using driver

A number of test helm charts and scripts are found in the directory test/helm. Product Guide provides descriptions of how to run these and explains how they work.

If you want to interact with the driver directly, you can use the Container Storage Client (csc) program provided via the GoCSI project:

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

(This is only recommended for developers.)

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

Get the driver's supported versions and driver info:

$ ./csc -v 0.1.0 -e csi.sock identity plugin-info
...
"url"="https://github.com/dell/csi-vxflexos"

Parameters

When using the driver, some commands accept additional parameters, some of which may be required for the command to work, or may change the behavior of the command. Those parameters are listed here.

CreateVolume: storagepool The name of a storage pool must be passed in the CreateVolume command
GetCapacity: storagepool may be passed in GetCapacity command. If it is, the returned capacity is the available capacity for creation within the given storage pool. Otherwise, it's the capacity for creation within the storage cluster.

Passing parameters with csc is demonstrated in this CreateVolume command:

$ ./csc -v 0.1.0 c create --cap 1,mount,xfs --params storagepool=pd1pool1 myvol
"6757e7d300000000"

Capable operational modes

The CSI spec defines a set of AccessModes that a volume can have. CSI-ScaleIO supports the following modes for volumes that will be mounted as a filesystem:

// 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;

This means that volumes can be mounted to either single node at a time, with read-write or read-only permission, or can be mounted on multiple nodes, but all must be read-only.

For volumes that are used as block devices, only the following are supported:

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

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

This means that giving a workload read-only access to a block device is not supported.

In general, volumes should be formatted with xfs or ext4.

Support

The CSI Driver for Dell EMC VxFlex OS image available on Dockerhub is officially supported by Dell EMC.

The source code available on Github is unsupported and provided solely under the terms of the license attached to the source code. For clarity, Dell EMC does not provide support for any source code modifications.

For any CSI driver setup, configuration issues, questions or feedback, join the Dell EMC Container community athttps://www.dell.com/community/Containers/bd-p/Containers

For any Dell EMC storage issues, please contact Dell support at: https://www.dell.com/support.

spiegela/csi-powerflex