Added upgrade story from manifest pod to ds

cluster/addons/fluentd-elasticsearch/fluentd-es-ds.yaml

@@ -34,6 +34,8 @@ spec:
         - name: varlibdockercontainers
           mountPath: /var/lib/docker/containers
           readOnly: true
+      nodeSelector:
+        alpha.kubernetes.io/fluentd-ds-ready: "true"
       terminationGracePeriodSeconds: 30
       volumes:
       - name: varlog

cluster/addons/fluentd-gcp/fluentd-gcp-ds.yaml

@@ -42,6 +42,8 @@ spec:
           readOnly: true
         - name: libsystemddir
           mountPath: /host/lib
+      nodeSelector:
+        alpha.kubernetes.io/fluentd-ds-ready: "true"
       terminationGracePeriodSeconds: 30
       volumes:
       - name: varlog

pkg/apis/meta/v1/well_known_labels.go

@@ -27,6 +27,12 @@ const (
 
 	LabelOS   = "beta.kubernetes.io/os"
 	LabelArch = "beta.kubernetes.io/arch"
+
+	// Historically fluentd was a manifest pod the was migrated to DaemonSet.
+	// To avoid situation during cluster upgrade when there are two instances
+	// of fluentd running on a node, kubelet need to mark node on which
+	// fluentd in not running as a manifest pod with LabelFluentdDsReady.
+	LabelFluentdDsReady = "alpha.kubernetes.io/fluentd-ds-ready"
 )
 
 // Role labels are applied to Nodes to mark their purpose.  In particular, we

pkg/kubelet/kubelet_node_status.go

@@ -193,9 +193,10 @@ func (kl *Kubelet) initialNode() (*v1.Node, error) {
 		ObjectMeta: v1.ObjectMeta{
 			Name: string(kl.nodeName),
 			Labels: map[string]string{
-				metav1.LabelHostname: kl.hostname,
-				metav1.LabelOS:       goruntime.GOOS,
-				metav1.LabelArch:     goruntime.GOARCH,
+				metav1.LabelHostname:       kl.hostname,
+				metav1.LabelOS:             goruntime.GOOS,
+				metav1.LabelArch:           goruntime.GOARCH,
+				metav1.LabelFluentdDsReady: "true",
 			},
 		},
 		Spec: v1.NodeSpec{