daemon: Handle osImageURL bootstrap

pkg/daemon/daemon.go

@@ -357,21 +357,26 @@ func (dn *Daemon) EnterDegradedState(err error) {
 //
 // If any of the object names are the same, they will be pointer-equal.
 type stateAndConfigs struct {
+	bootstrapping bool
 	state         string
 	currentConfig *mcfgv1.MachineConfig
 	pendingConfig *mcfgv1.MachineConfig
 	desiredConfig *mcfgv1.MachineConfig
 }
 
 func (dn *Daemon) getStateAndConfigs(pendingConfigName string) (*stateAndConfigs, error) {
-	state, err := getNodeAnnotationExt(dn.kubeClient.CoreV1().Nodes(), dn.name, MachineConfigDaemonStateAnnotationKey, true)
+	_, err := os.Lstat(InitialNodeAnnotationsFilePath)
+	bootstrapping := false
 	if err != nil {
-		return nil, err
-	}
-	// Temporary hack: the MCS used to not write the state=done annotation
-	// key.  If it's unset, let's write it now.
-	if state == "" {
-		state = MachineConfigDaemonStateDone
+		if os.IsNotExist(err) {
+			// The node annotation file (laid down by the MCS)
+			// doesn't exist, we must not be bootstrapping
+		} else {
+			return nil, err
+		}
+	} else {
+		bootstrapping = true
+		glog.Infof("In bootstrap mode")
 	}
 
 	currentConfigName, err := getNodeAnnotation(dn.kubeClient.CoreV1().Nodes(), dn.name, CurrentMachineConfigAnnotationKey)
@@ -386,6 +391,16 @@ func (dn *Daemon) getStateAndConfigs(pendingConfigName string) (*stateAndConfigs
 	if err != nil {
 		return nil, err
 	}
+	state, err := getNodeAnnotationExt(dn.kubeClient.CoreV1().Nodes(), dn.name, MachineConfigDaemonStateAnnotationKey, true)
+	if err != nil {
+		return nil, err
+	}
+	// Temporary hack: the MCS used to not write the state=done annotation
+	// key.  If it's unset, let's write it now.
+	if state == "" {
+		state = MachineConfigDaemonStateDone
+	}
+
 	var desiredConfig *mcfgv1.MachineConfig
 	if currentConfigName == desiredConfigName {
 		desiredConfig = currentConfig
@@ -415,6 +430,7 @@ func (dn *Daemon) getStateAndConfigs(pendingConfigName string) (*stateAndConfigs
 	}
 
 	return &stateAndConfigs{
+		bootstrapping: bootstrapping,
 		currentConfig: currentConfig,
 		pendingConfig: pendingConfig,
 		desiredConfig: desiredConfig,
@@ -540,6 +556,22 @@ func (dn *Daemon) CheckStateOnBoot() error {
 		select {}
 	}
 
+	if state.bootstrapping {
+		if !dn.checkOS(state.currentConfig.Spec.OSImageURL) {
+			glog.Infof("Bootstrap pivot required")
+			// This only returns on error
+			return dn.updateOSAndReboot(state.currentConfig)
+		} else {
+			glog.Infof("No bootstrap pivot required; unlinking bootstrap node annotations")
+			// Delete the bootstrap node annotations; the
+			// currentConfig's osImageURL should now be *truth*.
+			// In other words if it drifts somehow, we go degraded.
+			if err := os.Remove(InitialNodeAnnotationsFilePath); err != nil {
+				return errors.Wrapf(err, "Removing initial node annotations file")
+			}
+		}
+	}
+
 	// Validate the on-disk state against what we *expect*.
 	//
 	// In the case where we're booting a node for the first time, or the MCD
@@ -742,10 +774,6 @@ func (dn *Daemon) completeUpdate(desiredConfigName string) error {
 // triggerUpdateWithMachineConfig starts the update. It queries the cluster for
 // the current and desired config if they weren't passed.
 func (dn *Daemon) triggerUpdateWithMachineConfig(currentConfig *mcfgv1.MachineConfig, desiredConfig *mcfgv1.MachineConfig) error {
-	if err := dn.nodeWriter.SetUpdateWorking(dn.kubeClient.CoreV1().Nodes(), dn.name); err != nil {
-		return err
-	}
-
 	if currentConfig == nil {
 		ccAnnotation, err := getNodeAnnotation(dn.kubeClient.CoreV1().Nodes(), dn.name, CurrentMachineConfigAnnotationKey)
 		if err != nil {

pkg/daemon/update.go

@@ -63,41 +63,16 @@ func (dn *Daemon) writePendingState(desiredConfig *mcfgv1.MachineConfig) error {
 	return replaceFileContentsAtomically(pathStateJSON, b)
 }
 
-// update the node to the provided node configuration.
-func (dn *Daemon) update(oldConfig, newConfig *mcfgv1.MachineConfig) error {
+// updateOSAndReboot is the last step in an update(), and it can also
+// be called as a special case for the "bootstrap pivot".
+func (dn *Daemon) updateOSAndReboot(newConfig *mcfgv1.MachineConfig) error {
 	var err error
 
-	oldConfigName := oldConfig.GetName()
-	newConfigName := newConfig.GetName()
-	glog.Infof("Checking reconcilable for config %v to %v", oldConfigName, newConfigName)
-	// make sure we can actually reconcile this state
-	reconcilableError := dn.reconcilable(oldConfig, newConfig)
-
-	if reconcilableError != nil {
-		msg := fmt.Sprintf("Can't reconcile config %v with %v: %v", oldConfigName, newConfigName, *reconcilableError)
-		if dn.recorder != nil {
-			dn.recorder.Eventf(newConfig, corev1.EventTypeWarning, "FailedToReconcile", msg)
-		}
-		dn.logSystem(msg)
-		return fmt.Errorf("%s", msg)
-	}
-
-	// update files on disk that need updating
-	if err = dn.updateFiles(oldConfig, newConfig); err != nil {
-		return err
-	}
-
 	if err = dn.updateOS(newConfig); err != nil {
 		return err
 	}
 
-	if err = dn.updateSSHKeys(newConfig.Spec.Config.Passwd.Users); err != nil {
-		return err
-	}
-
-	// TODO: Change the logic to be clearer
-	// We need to skip draining of the node when we are running once
-	// and there is no cluster.
+	// Skip draining of the node when we're not cluster driven
 	if dn.onceFrom == "" {
 		glog.Info("Update prepared; draining the node")
 
@@ -120,12 +95,49 @@ func (dn *Daemon) update(oldConfig, newConfig *mcfgv1.MachineConfig) error {
 		glog.V(2).Infof("Node successfully drained")
 	}
 
+	// reboot. this function shouldn't actually return.
+	return dn.reboot(fmt.Sprintf("Node will reboot into config %v", newConfig.GetName()))
+}
+
+// update the node to the provided node configuration.
+func (dn *Daemon) update(oldConfig, newConfig *mcfgv1.MachineConfig) error {
+	var err error
+
+	if dn.nodeWriter != nil {
+		if err = dn.nodeWriter.SetUpdateWorking(dn.kubeClient.CoreV1().Nodes(), dn.name); err != nil {
+			return err
+		}
+	}
+
+	oldConfigName := oldConfig.GetName()
+	newConfigName := newConfig.GetName()
+	glog.Infof("Checking reconcilable for config %v to %v", oldConfigName, newConfigName)
+	// make sure we can actually reconcile this state
+	reconcilableError := dn.reconcilable(oldConfig, newConfig)
+
+	if reconcilableError != nil {
+		msg := fmt.Sprintf("Can't reconcile config %v with %v: %v", oldConfigName, newConfigName, *reconcilableError)
+		if dn.recorder != nil {
+			dn.recorder.Eventf(newConfig, corev1.EventTypeWarning, "FailedToReconcile", msg)
+		}
+		dn.logSystem(msg)
+		return fmt.Errorf("%s", msg)
+	}
+
+	// update files on disk that need updating
+	if err = dn.updateFiles(oldConfig, newConfig); err != nil {
+		return err
+	}
+
+	if err = dn.updateSSHKeys(newConfig.Spec.Config.Passwd.Users); err != nil {
+		return err
+	}
+
 	if err = dn.writePendingState(newConfig); err != nil {
 		return errors.Wrapf(err, "writing pending state")
 	}
 
-	// reboot. this function shouldn't actually return.
-	return dn.reboot(fmt.Sprintf("Node will reboot into config %v", newConfigName))
+	return dn.updateOSAndReboot(newConfig)
 }
 
 // reconcilable checks the configs to make sure that the only changes requested