fix: supports seamless upgrade socket path name with uid

cmd/dra-example-kubeletplugin/driver.go

@@ -53,15 +53,22 @@ func NewDriver(ctx context.Context, config *Config) (*driver, error) {
 	}
 	driver.state = state
 
-	helper, err := kubeletplugin.Start(
-		ctx,
-		driver,
+	kubeletPluginOptions := []kubeletplugin.Option{
 		kubeletplugin.KubeClient(config.coreclient),
 		kubeletplugin.NodeName(config.flags.nodeName),
 		kubeletplugin.DriverName(consts.DriverName),
 		kubeletplugin.RegistrarDirectoryPath(config.flags.kubeletRegistrarDirectoryPath),
 		kubeletplugin.PluginDataDirectoryPath(config.DriverPluginPath()),
-	)
+	}
+
+	// Enable seamless upgrades when both seamless upgrades are enabled and POD_UID is available
+	if config.flags.seamlessUpgrades && config.flags.podUID != "" {
+		kubeletPluginOptions = append(kubeletPluginOptions,
+			kubeletplugin.RollingUpdate(types.UID(config.flags.podUID)),
+		)
+	}
+
+	helper, err := kubeletplugin.Start(ctx, driver, kubeletPluginOptions...)
 	if err != nil {
 		return nil, err
 	}

cmd/dra-example-kubeletplugin/health.go

@@ -63,9 +63,12 @@ func startHealthcheck(ctx context.Context, config *Config) (*healthcheck, error)
 
 	regSockPath := (&url.URL{
 		Scheme: "unix",
-		// TODO: this needs to adapt when seamless upgrades
-		// are enabled and the filename includes a uid.
-		Path: path.Join(config.flags.kubeletRegistrarDirectoryPath, consts.DriverName+"-reg.sock"),
+		Path: func() string {
+			if config.flags.seamlessUpgrades && config.flags.podUID != "" {
+				return path.Join(config.flags.kubeletRegistrarDirectoryPath, consts.DriverName+"-"+config.flags.podUID+"-reg.sock")
+			}
+			return path.Join(config.flags.kubeletRegistrarDirectoryPath, consts.DriverName+"-reg.sock")
+		}(),
 	}).String()
 	log.Info("connecting to registration socket", "path", regSockPath)
 	regConn, err := grpc.NewClient(
@@ -78,7 +81,12 @@ func startHealthcheck(ctx context.Context, config *Config) (*healthcheck, error)
 
 	draSockPath := (&url.URL{
 		Scheme: "unix",
-		Path:   path.Join(config.DriverPluginPath(), "dra.sock"),
+		Path: func() string {
+			if config.flags.seamlessUpgrades && config.flags.podUID != "" {
+				return path.Join(config.DriverPluginPath(), "dra-"+config.flags.podUID+".sock")
+			}
+			return path.Join(config.DriverPluginPath(), "dra.sock")
+		}(),
 	}).String()
 	log.Info("connecting to DRA socket", "path", draSockPath)
 	draConn, err := grpc.NewClient(

cmd/dra-example-kubeletplugin/main.go

@@ -49,6 +49,8 @@ type Flags struct {
 	kubeletRegistrarDirectoryPath string
 	kubeletPluginsDirectoryPath   string
 	healthcheckPort               int
+	podUID                        string
+	seamlessUpgrades              bool
 }
 
 type Config struct {
@@ -115,6 +117,18 @@ func newApp() *cli.App {
 			Destination: &flags.healthcheckPort,
 			EnvVars:     []string{"HEALTHCHECK_PORT"},
 		},
+		&cli.StringFlag{
+			Name:        "pod-uid",
+			Usage:       "UID of the pod (used for seamless upgrades to create unique socket names).",
+			Destination: &flags.podUID,
+			EnvVars:     []string{"POD_UID"},
+		},
+		&cli.BoolFlag{
+			Name:        "seamless-upgrades",
+			Usage:       "Enable seamless upgrades support. When enabled, the driver will use rolling update mode if pod-uid is available.",
+			Destination: &flags.seamlessUpgrades,
+			EnvVars:     []string{"SEAMLESS_UPGRADES"},
+		},
 	}
 	cliFlags = append(cliFlags, flags.kubeClientConfig.Flags()...)
 	cliFlags = append(cliFlags, flags.loggingConfig.Flags()...)

deployments/helm/dra-example-driver/templates/kubeletplugin.yaml

@@ -14,7 +14,38 @@ spec:
       app.kubernetes.io/component: kubeletplugin
   {{- with .Values.kubeletPlugin.updateStrategy }}
   updateStrategy:
+    {{- if $.Values.kubeletPlugin.seamlessUpgrades.enabled }}
+    {{- $strategy := . }}
+    {{- range $key, $value := . }}
+    {{- if eq $key "rollingUpdate" }}
+    {{ $key }}:
+      maxSurge: 1
+      maxUnavailable: 0
+      {{- range $subkey, $subvalue := $value }}
+      {{- if and (ne $subkey "maxSurge") (ne $subkey "maxUnavailable") }}
+      {{ $subkey }}: {{ $subvalue }}
+      {{- end }}
+      {{- end }}
+    {{- else }}
+    {{ $key }}: {{ $value }}
+    {{- end }}
+    {{- end }}
+    {{- else }}
     {{- toYaml . | nindent 4 }}
+    {{- end }}
+  {{- else }}
+  updateStrategy:
+    type: {{ .Values.kubeletPlugin.updateStrategy.type | default "RollingUpdate" }}
+    {{- if eq (.Values.kubeletPlugin.updateStrategy.type | default "RollingUpdate") "RollingUpdate" }}
+    rollingUpdate:
+      {{- if .Values.kubeletPlugin.seamlessUpgrades.enabled }}
+      maxSurge: 1
+      maxUnavailable: 0
+      {{- else }}
+      maxSurge: {{ .Values.kubeletPlugin.updateStrategy.rollingUpdate.maxSurge | default 0 }}
+      maxUnavailable: {{ .Values.kubeletPlugin.updateStrategy.rollingUpdate.maxUnavailable | default 1 }}
+      {{- end }}
+    {{- end }}
   {{- end }}
   template:
     metadata:
@@ -80,6 +111,14 @@ spec:
         - name: HEALTHCHECK_PORT
           value: {{ .Values.kubeletPlugin.containers.plugin.healthcheckPort | quote }}
         {{- end }}
+        - name: POD_UID
+          valueFrom:
+            fieldRef:
+              fieldPath: metadata.uid
+        {{- if .Values.kubeletPlugin.seamlessUpgrades.enabled }}
+        - name: SEAMLESS_UPGRADES
+          value: "true"
+        {{- end }}
         volumeMounts:
         - name: plugins-registry
           mountPath: {{ .Values.kubeletPlugin.kubeletRegistrarDirectoryPath | quote }}

deployments/helm/dra-example-driver/values.yaml

@@ -47,6 +47,8 @@ controller:
 kubeletPlugin:
   numDevices: 8
   priorityClassName: "system-node-critical"
+  seamlessUpgrades:
+    enabled: true
   updateStrategy:
     type: RollingUpdate
   podAnnotations: {}