kubeadm: skip addons phase on worker node

cmd/kubeadm/app/cmd/phases/upgrade/addons.go

@@ -73,21 +73,26 @@ func shouldUpgradeAddons(client clientset.Interface, cfg *kubeadmapi.InitConfigu
 	return true, nil
 }
 
-func getInitData(c workflow.RunData) (*kubeadmapi.InitConfiguration, clientset.Interface, string, io.Writer, bool, error) {
+func getInitData(c workflow.RunData) (*kubeadmapi.InitConfiguration, clientset.Interface, string, io.Writer, bool, bool, error) {
 	data, ok := c.(Data)
 	if !ok {
-		return nil, nil, "", nil, false, errors.New("addon phase invoked with an invalid data struct")
+		return nil, nil, "", nil, false, false, errors.New("addon phase invoked with an invalid data struct")
 	}
-	return data.InitCfg(), data.Client(), data.PatchesDir(), data.OutputWriter(), data.DryRun(), nil
+	return data.InitCfg(), data.Client(), data.PatchesDir(), data.OutputWriter(), data.DryRun(), data.IsControlPlaneNode(), nil
 }
 
 // runCoreDNSAddon upgrades the CoreDNS addon.
 func runCoreDNSAddon(c workflow.RunData) error {
-	cfg, client, patchesDir, out, dryRun, err := getInitData(c)
+	cfg, client, patchesDir, out, dryRun, isControlPlaneNode, err := getInitData(c)
 	if err != nil {
 		return err
 	}
 
+	if !isControlPlaneNode {
+		fmt.Println("[upgrade/addon] Skipping addon/coredns phase. Not a control plane node.")
+		return nil
+	}
+
 	shouldUpgradeAddons, err := shouldUpgradeAddons(client, cfg, out)
 	if err != nil {
 		return err
@@ -105,11 +110,16 @@ func runCoreDNSAddon(c workflow.RunData) error {
 
 // runKubeProxyAddon upgrades the kube-proxy addon.
 func runKubeProxyAddon(c workflow.RunData) error {
-	cfg, client, _, out, dryRun, err := getInitData(c)
+	cfg, client, _, out, dryRun, isControlPlaneNode, err := getInitData(c)
 	if err != nil {
 		return err
 	}
 
+	if !isControlPlaneNode {
+		fmt.Println("[upgrade/addon] Skipping addon/kube-proxy phase. Not a control plane node.")
+		return nil
+	}
+
 	shouldUpgradeAddons, err := shouldUpgradeAddons(client, cfg, out)
 	if err != nil {
 		return err

cmd/kubeadm/app/cmd/phases/upgrade/apply/data_test.go

@@ -36,6 +36,7 @@ func (t *testData) RenewCerts() bool                        { return false }
 func (t *testData) DryRun() bool                            { return false }
 func (t *testData) Cfg() *kubeadmapi.UpgradeConfiguration   { return nil }
 func (t *testData) InitCfg() *kubeadmapi.InitConfiguration  { return nil }
+func (t *testData) IsControlPlaneNode() bool                { return false }
 func (t *testData) Client() clientset.Interface             { return nil }
 func (t *testData) IgnorePreflightErrors() sets.Set[string] { return nil }
 func (t *testData) PatchesDir() string                      { return "" }

cmd/kubeadm/app/cmd/phases/upgrade/data.go

@@ -33,6 +33,7 @@ type Data interface {
 	DryRun() bool
 	Cfg() *kubeadmapi.UpgradeConfiguration
 	InitCfg() *kubeadmapi.InitConfiguration
+	IsControlPlaneNode() bool
 	Client() clientset.Interface
 	IgnorePreflightErrors() sets.Set[string]
 	PatchesDir() string

cmd/kubeadm/app/cmd/phases/upgrade/data_test.go

@@ -36,6 +36,7 @@ func (t *testData) RenewCerts() bool                        { return false }
 func (t *testData) DryRun() bool                            { return false }
 func (t *testData) Cfg() *kubeadmapi.UpgradeConfiguration   { return nil }
 func (t *testData) InitCfg() *kubeadmapi.InitConfiguration  { return nil }
+func (t *testData) IsControlPlaneNode() bool                { return false }
 func (t *testData) Client() clientset.Interface             { return nil }
 func (t *testData) IgnorePreflightErrors() sets.Set[string] { return nil }
 func (t *testData) PatchesDir() string                      { return "" }

cmd/kubeadm/app/cmd/phases/upgrade/node/data.go

@@ -26,6 +26,5 @@ import (
 type Data interface {
 	upgrade.Data
 
-	IsControlPlaneNode() bool
 	KubeConfigPath() string
 }

cmd/kubeadm/app/cmd/upgrade/apply.go

@@ -351,3 +351,9 @@ func (d *applyData) AllowRCUpgrades() bool {
 func (d *applyData) ForceUpgrade() bool {
 	return d.force
 }
+
+// IsControlPlaneNode returns if the node is a control-plane node.
+func (d *applyData) IsControlPlaneNode() bool {
+	// `kubeadm upgrade apply` should always be executed on a control-plane node
+	return true
+}