Allow running the controller service separately

Dockerfile

@@ -15,7 +15,7 @@
 FROM golang:1.12.7-stretch as builder
 WORKDIR /go/src/github.com/kubernetes-sigs/aws-ebs-csi-driver
 ADD . .
-RUN make 
+RUN make
 
 FROM amazonlinux:2
 RUN yum install ca-certificates e2fsprogs xfsprogs util-linux -y

aws-ebs-csi-driver/templates/manifest.yaml

@@ -215,6 +215,12 @@ spec:
           image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
           args:
             - --endpoint=$(CSI_ENDPOINT)
+            {{- if .Values.region }}
+            - --region={{ .Values.region }}
+            {{- end }}
+            {{- if .Values.runAsController }}
+            - --run-as-controller={{ .Values.runAsController }}
+            {{- end }}
             - --logtostderr
             - --v=5
             {{ include "aws-ebs-csi-driver.extra-volume-tags" . }}

aws-ebs-csi-driver/values.yaml

@@ -48,3 +48,5 @@ affinity: {}
 #   key1: value1
 #   key2: value2
 extraVolumeTags: {}
+region: ""
+runAsController: false

cmd/main.go

@@ -28,14 +28,18 @@ import (
 
 func main() {
 	var (
-		version         bool
 		endpoint        string
 		extraVolumeTags map[string]string
+		region          string
+		runAsController bool
+		version         bool
 	)
 
-	flag.BoolVar(&version, "version", false, "Print the version and exit.")
 	flag.StringVar(&endpoint, "endpoint", driver.DefaultCSIEndpoint, "CSI Endpoint")
 	flag.Var(cliflag.NewMapStringString(&extraVolumeTags), "extra-volume-tags", "Extra volume tags to attach to each dynamically provisioned volume. It is a comma separated list of key value pairs like '<key1>=<value1>,<key2>=<value2>'")
+	flag.StringVar(&region, "region", "", "If specified then the given AWS region will be taken instead of trying to look it up via the AWS EC2 metadata service.")
+	flag.BoolVar(&runAsController, "run-as-controller", false, "If set to true then the CSI driver runs the controller only and does not start the node service.")
+	flag.BoolVar(&version, "version", false, "Print the version and exit.")
 
 	klog.InitFlags(nil)
 	flag.Parse()
@@ -52,6 +56,8 @@ func main() {
 	drv, err := driver.NewDriver(
 		driver.WithEndpoint(endpoint),
 		driver.WithExtraVolumeTags(extraVolumeTags),
+		driver.WithRegion(region),
+		driver.WithRunAsController(runAsController),
 	)
 	if err != nil {
 		klog.Fatalln(err)

deploy/kubernetes/base/controller.yaml

@@ -28,6 +28,8 @@ spec:
           args :
             - --endpoint=$(CSI_ENDPOINT)
             - --logtostderr
+          # - --region=us-east-1 # overwrite the AWS region instead of looking it up dynamically via the AWS EC2 metadata svc
+          # - --run-as-controller=true # only run the controller service of the driver
             - --v=5
           env:
             - name: CSI_ENDPOINT

docs/design.md

@@ -216,3 +216,13 @@ Blindly return:
   rpc:
     - STAGE\_UNSTAGE\_VOLUME
 ```
+
+## Running the controller separately
+
+Traditionally, you run the CSI controllers with the EBS driver in the same Kubernetes cluster.
+Though, in some scenarios you might want to run the CSI controllers (csi-provisioner, csi-attacher, etc.) together with the EBS controller service of this driver separately from the Kubernetes cluster it serves (while the EBS driver with an activated node service still runs inside the cluster).
+Also, this may not necessarily have to be an AWS EC2 instance.
+To support these cases, the AWS EBS CSI driver plugin supports two command line flags:
+
+* `--region=<...>` which allows you to specify the AWS region the served Kubernetes cluster is deployed to (if not specified then the controller service of the EBS driver will try to look the region up dynamically via the AWS EC2 metadata service).
+* `--run-as-controller=true` which allows you to only start the controller service (and not the node service) of the EBS driver.

go.sum

@@ -48,6 +48,7 @@ github.com/codedellemc/goscaleio v0.0.0-20170830184815-20e2ce2cf885/go.mod h1:JI
 github.com/codegangsta/negroni v1.0.0/go.mod h1:v0y3T5G7Y1UlFfyxFn/QLRU4a2EuNau2iZY63YTKWo0=
 github.com/container-storage-interface/spec v1.1.0 h1:qPsTqtR1VUPvMPeK0UnCZMtXaKGyyLPG8gj/wG6VqMs=
 github.com/container-storage-interface/spec v1.1.0/go.mod h1:6URME8mwIBbpVyZV93Ce5St17xBiQJQY67NDsuohiy4=
+github.com/container-storage-interface/spec v1.2.0 h1:bD9KIVgaVKKkQ/UbVUY9kCaH/CJbhNxe0eeB4JeJV2s=
 github.com/containerd/console v0.0.0-20170925154832-84eeaae905fa/go.mod h1:Tj/on1eG8kiEhd0+fhSDzsPAFESxzBBvdyEgyryXffw=
 github.com/containerd/containerd v1.0.2/go.mod h1:bC6axHOhabU15QhwfG7w5PipXdVtMXFTttgp+kVtyUA=
 github.com/containerd/typeurl v0.0.0-20190228175220-2a93cfde8c20/go.mod h1:Cm3kwCdlkCfMSHURc+r6fwoGH6/F1hH3S4sg0rLFWPc=

pkg/driver/controller.go

@@ -59,11 +59,15 @@ type controllerService struct {
 // newControllerService creates a new controller service
 // it panics if failed to create the service
 func newControllerService(driverOptions *DriverOptions) controllerService {
-	metadata, err := cloud.NewMetadata()
-	if err != nil {
-		panic(err)
+	region := driverOptions.region
+	if region == "" {
+		metadata, err := cloud.NewMetadata()
+		if err != nil {
+			panic(err)
+		}
+		region = metadata.GetRegion()
 	}
-	region := metadata.GetRegion()
+
 	cloud, err := cloud.NewCloud(region)
 	if err != nil {
 		panic(err)

pkg/driver/driver.go

@@ -43,13 +43,16 @@ type Driver struct {
 type DriverOptions struct {
 	endpoint        string
 	extraVolumeTags map[string]string
+	region          string
+	runAsController bool
 }
 
 func NewDriver(options ...func(*DriverOptions)) (*Driver, error) {
 	klog.Infof("Driver: %v Version: %v", DriverName, driverVersion)
 
 	driverOptions := DriverOptions{
-		endpoint: DefaultCSIEndpoint,
+		endpoint:        DefaultCSIEndpoint,
+		runAsController: false,
 	}
 	for _, option := range options {
 		option(&driverOptions)
@@ -61,10 +64,13 @@ func NewDriver(options ...func(*DriverOptions)) (*Driver, error) {
 
 	driver := Driver{
 		controllerService: newControllerService(&driverOptions),
-		nodeService:       newNodeService(),
 		options:           &driverOptions,
 	}
 
+	if driverOptions.runAsController {
+		driver.nodeService = newNodeService()
+	}
+
 	return &driver, nil
 }
 
@@ -110,6 +116,18 @@ func WithEndpoint(endpoint string) func(*DriverOptions) {
 	}
 }
 
+func WithRegion(region string) func(*DriverOptions) {
+	return func(o *DriverOptions) {
+		o.region = region
+	}
+}
+
+func WithRunAsController(runAsController bool) func(*DriverOptions) {
+	return func(o *DriverOptions) {
+		o.runAsController = runAsController
+	}
+}
+
 func WithExtraVolumeTags(extraVolumeTags map[string]string) func(*DriverOptions) {
 	return func(o *DriverOptions) {
 		o.extraVolumeTags = extraVolumeTags