controller/template: put the cloudconf for kubelet behind platform gate

pkg/controller/template/render.go

@@ -365,14 +365,22 @@ func cloudProvider(cfg RenderConfig) (interface{}, error) {
 // Process the {{cloudConfigFlag .}}
 // If the CloudProviderConfig field is set and not empty, this
 // returns the cloud conf flag for kubelet [1] pointing the kubelet to use
-// /etc/kubernetes/cloud.conf for configuring the cloud provider.
+// /etc/kubernetes/cloud.conf for configuring the cloud provider for select platforms.
+// By default even if CloudProviderConfig fields is set, the kubelet will be configured to used for
+// select platforms only.
 //
 // [1]: https://kubernetes.io/docs/reference/command-line-tools-reference/kubelet/#options
 func cloudConfigFlag(cfg RenderConfig) interface{} {
-	if len(cfg.CloudProviderConfig) > 0 {
-		return "--cloud-config=/etc/kubernetes/cloud.conf"
+	if len(cfg.CloudProviderConfig) == 0 {
+		return ""
+	}
+	flag := "--cloud-config=/etc/kubernetes/cloud.conf"
+	switch cfg.Platform {
+	case platformAzure, platformOpenstack:
+		return flag
+	default:
+		return ""
 	}
-	return ""
 }
 
 // existsDir returns true if path exists and is a directory, false if the path

pkg/controller/template/render_test.go

@@ -65,6 +65,57 @@ func TestCloudProvider(t *testing.T) {
 	}
 }
 
+func TestCloudConfigFlag(t *testing.T) {
+	dummyTemplate := []byte(`{{cloudConfigFlag .}}`)
+
+	cases := []struct {
+		platform string
+		content  string
+		res      string
+	}{{
+		platform: "aws",
+		content:  "",
+		res:      "",
+	}, {
+		platform: "azure",
+		content:  "",
+		res:      "",
+	}, {
+		platform: "aws",
+		content: `
+[dummy-config]
+    option = a
+`,
+		res: "",
+	}, {
+		platform: "azure",
+		content: `
+[dummy-config]
+    option = a
+`,
+		res: "--cloud-config=/etc/kubernetes/cloud.conf",
+	}}
+	for idx, c := range cases {
+		name := fmt.Sprintf("case #%d", idx)
+		t.Run(name, func(t *testing.T) {
+			config := &mcfgv1.ControllerConfig{
+				Spec: mcfgv1.ControllerConfigSpec{
+					Platform:            c.platform,
+					CloudProviderConfig: c.content,
+				},
+			}
+			got, err := renderTemplate(RenderConfig{&config.Spec, `{"dummy":"dummy"}`}, name, dummyTemplate)
+			if err != nil {
+				t.Fatalf("expected nil error %v", err)
+			}
+
+			if string(got) != c.res {
+				t.Fatalf("mismatch got: %s want: %s", got, c.res)
+			}
+		})
+	}
+}
+
 func TestEtcdPeerCertDNSNames(t *testing.T) {
 	dummyTemplate := []byte(`{{etcdPeerCertDNSNames .}}`)
 

pkg/controller/template/test_data/templates/master/01-master-kubelet/vsphere/units/kubelet.service

@@ -25,7 +25,7 @@ contents: |
         --client-ca-file=/etc/kubernetes/ca.crt \
         --cloud-provider=vsphere \
         --volume-plugin-dir=/etc/kubernetes/kubelet-plugins/volume/exec \
-        --cloud-config=/etc/kubernetes/cloud.conf \
+         \
         --anonymous-auth=false \
         --register-with-taints=node-role.kubernetes.io/master=:NoSchedule \
 

pkg/controller/template/test_data/templates/worker/01-worker-kubelet/vsphere/units/kubelet.service

@@ -24,7 +24,7 @@ contents: |
         --volume-plugin-dir=/etc/kubernetes/kubelet-plugins/volume/exec \
         --client-ca-file=/etc/kubernetes/ca.crt \
         --cloud-provider=vsphere \
-        --cloud-config=/etc/kubernetes/cloud.conf \
+         \
         --anonymous-auth=false \
 
   Restart=always