[WIP] kubeadm: implement reset flow

components/kubeadm/action.proto

@@ -29,7 +29,7 @@ message Kubelet { // TODO: move to node package
   NodeAuthInfo bootstrap_auth_info = 1;
   map<string, string> node_labels = 2;
   string node_ip = 3;
-  // List of taints to assign using the kubelet flag, in the format "key=value:effect"
+  // List of taints to assign using the kubelet flag
   repeated Taint register_with_taints = 4;
 }
 
@@ -47,4 +47,17 @@ message KubeadmNodeJoinSpec {
 
 message KubeadmNodeJoinStatus {
 
-}
+}
+
+message KubeadmNodeReset {
+  api.Metadata metadata = 1;
+
+  KubeadmNodeResetSpec spec = 2;
+
+  KubeadmNodeResetStatus status = 3;
+}
+
+
+message KubeadmNodeResetSpec {}
+
+message KubeadmNodeResetStatus {}

components/kubeadm/redact.go

@@ -1,5 +1,7 @@
 package kubeadm
 
+func (x *KubeadmNodeReset) Redact() {}
+
 func (x *KubeadmNodeJoin) Redact() {
 	if x == nil {
 		return

components/kubeadm/reset.go

@@ -0,0 +1,41 @@
+package kubeadm
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/Azure/AKSFlexNode/pkg/config"
+)
+
+// kubernetesDirs are directories created during a kubeadm join that must be
+// removed to fully reset the node. kubeadm reset cleans most of these, but
+// may leave some behind depending on the runtime state.
+//
+// ref: https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-reset/
+var kubernetesDirs = []string{
+	config.KubeletRoot,         // /var/lib/kubelet
+	config.KubernetesConfigDir, // /etc/kubernetes — config, PKI, manifests
+	config.DefaultCNIConfigDir, // /etc/cni/net.d — CNI configuration written during join
+	config.KubernetesRunDir,    // /var/run/kubernetes — runtime sockets and PID files
+	config.CNIStateDir,         // /var/lib/cni — CNI state data
+}
+
+// RemoveKubernetesDirs removes directories created during a kubeadm join.
+// Removal is best-effort across all paths: every directory is attempted
+// even if earlier ones fail. The first error encountered is returned.
+//
+// FIXME: find a better place to put this function for reusing with kubelet component
+func RemoveKubernetesDirs() error {
+	var errs []error
+	for _, dir := range kubernetesDirs {
+		if err := os.RemoveAll(dir); err != nil {
+			errs = append(errs, fmt.Errorf("remove %s: %w", dir, err))
+		}
+	}
+
+	if len(errs) > 0 {
+		return fmt.Errorf("cleanup kubernetes directories: %w", errs[0])
+	}
+
+	return nil
+}

components/kubeadm/v20260301/exports.go

@@ -10,4 +10,8 @@ func init() {
 		newNodeJoinAction,
 		&kubeadm.KubeadmNodeJoin{},
 	)
+	actions.MustRegister(
+		newNodeResetAction,
+		&kubeadm.KubeadmNodeReset{},
+	)
 }