From 9318020f59ef1c9b66cb76b8df041b978c246597 Mon Sep 17 00:00:00 2001
From: Vladimir Popov <vladimir.popov@xored.com>
Date: Mon, 18 Jan 2021 13:40:32 +0700
Subject: [PATCH] Add documentation

Signed-off-by: Vladimir Popov <vladimir.popov@xored.com>
---
 README.md | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 main.go   |  4 ++--
 2 files changed, 52 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index bf078929..a33a68eb 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,52 @@
+# Intro
+
+This repo contains 'cmd-forwarder-sriov' a SR-IOV based forwarder application for Network Service Mesh. 
+
+This README will provide directions for building, testing, and debugging that container.
+
+# Usage
+
+SR-IOV forwarder binds one of the free VFs from the list of the configured PFs for each client request. It supports 2
+mechanisms for the client:
+* KERNEL_INTERFACE - binds VF to the kernel driver and passes kernel interface to the client net NS
+* VFIO - binds VF to the vfio-pci driver and gives permissions to the client pod to work with the VF device
+
+Also it works as a device plugin server providing resources for the client pods. Each configured PF adds _VF count_
+`serviceDomain/capalility` resources for every `{ serviceDomain, capability }` pair.
+
+## Environment config
+
+`cmd-forwarder-sriov` accept following environment variables:
+
+* `NSM_NAME` - A string value of forwarder network service endpoint name (default `sriov-forwarder`)
+* `NSM_NS_NAME` - A string value of forwarder network service name (default `sriovns`)
+* `NSM_CONNECT_TO` - A Network Service Manager connectTo URL (default `unix:///var/lib/networkservicemesh/nsm.io.sock`)
+* `NSM_MAX_TOKEN_LIFETIME` - A token lifetime duration (default `24h`)
+* `NSM_RESOURCE_POLL_TIMEOUT` - A timeout to poll device plugin resources usage from kubelet API (default `30s`)
+* `NSM_DEVICE_PLUGIN_PATH` - Path to the device plugin directory (default `/var/lib/kubelet/device-plugins/`)
+* `NSM_POD_RESOURCES_PATH` - Path to the pod resources directory (default `/var/lib/kubelet/pod-resources/`)
+* `NSM_SRIOV_CONFIG_FILE` - Path to the config file (default `./pci.config`)
+* `NSM_PCI_DEVICES_PATH` - Path to the PCI devices directory (default `/sys/bus/pci/devices`)
+* `NSM_PCI_DRIVERS_PATH` - Path to the PCI drivers directory (default `/sys/bus/pci/drivers`)
+* `NSM_CGROUP_PATH` - Path to the host `/sys/fs/cgroup/devices` directory (default `/host/sys/fs/cgroup/devices`)
+* `NSM_VFIO_PATH` - Path to the host `/dev/vfio` directory (default `/host/dev/vfio`)
+
+## Config file
+
+`cmd-forwarder-sriov` requires configuration file in the following format:
+```yaml
+---
+physicalFunctions:            # map [PCI address -> PF] for all supported PFs
+  0000:01:00.0:
+    pfKernelDriver: pf-driver # PF kernel driver
+    vfKernelDriver: vf-driver # VFs kernel driver
+    capabilities:             # list of the capabilities supported by the PF
+      - intel
+      - 10G
+    serviceDomains:           # list of the service domains supported by the PF
+      - service.domain.1
+```
+
 # Build
 
 ## Build cmd binary locally
@@ -76,7 +125,7 @@ through to the point of running cmd, you will not be able to attach a debugger o
 
 ## A Note on Running golangci-lint
 
-Because cmd-forwarder-vppagent is only anticipated to run in Linux, you will need to run golangci-lint run with:
+Because cmd-forwarder-sriov is only anticipated to run in Linux, you will need to run golangci-lint run with:
 
 ```go
 GOOS=linux golangci-lint run
diff --git a/main.go b/main.go
index e264e55c..cd4352f9 100644
--- a/main.go
+++ b/main.go
@@ -61,9 +61,9 @@ import (
 
 // Config - configuration for cmd-forwarder-sriov
 type Config struct {
-	Name                string        `default:"sriov-forwarder" desc:"Name of Endpoint"`
+	Name                string        `default:"sriov-forwarder" desc:"name of Endpoint"`
 	NSName              string        `default:"sriovns" desc:"Name of Network Service to Register with Registry"`
-	ConnectTo           url.URL       `default:"unix:///connect.to.socket" desc:"url to connect to" split_words:"true"`
+	ConnectTo           url.URL       `default:"unix:///var/lib/networkservicemesh/nsm.io.sock" desc:"URL to connect to" split_words:"true"`
 	MaxTokenLifetime    time.Duration `default:"24h" desc:"maximum lifetime of tokens" split_words:"true"`
 	ResourcePollTimeout time.Duration `default:"30s" desc:"device plugin polling timeout" split_words:"true"`
 	DevicePluginPath    string        `default:"/var/lib/kubelet/device-plugins/" desc:"path to the device plugin directory" split_words:"true"`