There is no such thing as a "passive" NameNode. Are you asking about the HA or non-HA configuration? In an HA configuration, there is Active NameNode that serves user requests. Standby NameNode that generates periodic checkpoints. It can also take over the role of the Active if the previously active NameNode dies or becomes unresponsive. In a non-HA configuration Primary NameNode that serves user requests. Secondary NameNode that generates periodic checkpoints. A secondary NameNode can never become the primary. The terminology is unfortunately confusing. ... View more