When the notification function is enabled, you will be notified of all the specified operations on your bucket.
By default, the notification function of your bucket is not enabled. Namely, the NotificationConfiguration element is null. If you want to disable the function, set the NotificationConfiguration element to null.
After receiving the notification request, OBS verifies whether the specified Simple Message Notification (SMN) topic exists and whether the topic is authorized to OBS. If the topic exists and is authorized to OBS, OBS sends a test notification to the topic.
The s3:PutBucketNotification permission is required to configure the notification function. By default, the permission is granted to the bucket owner only. However, it can be granted to other users by configuring the bucket policy.
For details about how to authorize topics to OBS, see the SMN User Manual.