diff --git a/pkg/harvester/mixins/harvester-vm/impl.js b/pkg/harvester/mixins/harvester-vm/impl.js
index 3c2ae101..8fd2fa92 100644
--- a/pkg/harvester/mixins/harvester-vm/impl.js
+++ b/pkg/harvester/mixins/harvester-vm/impl.js
@@ -38,6 +38,10 @@ export const SSH_EXISTING_TYPE = {
 export default {
   methods: {
     hasCloudConfigComment(userScript) {
+      if (typeof userScript === 'string' && /^\s*#cloud-config(\s|$)/.test(userScript)) {
+        return true;
+      }
+
       // Check that userData contains: #cloud-config
       const userDataDoc = userScript ? YAML.parseDocument(userScript) : YAML.parseDocument({});
       const items = userDataDoc?.contents?.items || [];
@@ -52,6 +56,14 @@ export default {
         exist = true;
       }
 
+      if (userDataDoc?.contents?.commentBefore === 'cloud-config' || userDataDoc?.contents?.commentBefore?.includes('cloud-config\n')) {
+        exist = true;
+      }
+
+      if (userDataDoc?.contents?.comment === 'cloud-config' || userDataDoc?.contents?.comment?.includes('cloud-config\n')) {
+        exist = true;
+      }
+
       items.map((item) => {
         const key = item.key;
 
diff --git a/pkg/harvester/mixins/harvester-vm/index.js b/pkg/harvester/mixins/harvester-vm/index.js
index e6b3b917..95951619 100644
--- a/pkg/harvester/mixins/harvester-vm/index.js
+++ b/pkg/harvester/mixins/harvester-vm/index.js
@@ -1211,9 +1211,10 @@ export default {
 
         userDataDoc = config.installAgent ? this.mergeQGA({ userDataDoc, ...config }) : this.deleteQGA({ userDataDoc, ...config });
         const userDataYaml = userDataDoc.toString();
+        const userDataValue = userDataDoc.toJSON();
 
-        if (userDataYaml === '{}\n') {
-          // When the YAML parsed value is '{}\n', it means that the userData is empty, then undefined is returned.
+        if (userDataValue === null || (typeof userDataValue === 'object' && !Array.isArray(userDataValue) && isEmpty(userDataValue))) {
+          // Empty userData should not create cloud-init content like `null`.
           return undefined;
         }