ZooKeeper supports mutual server-to-server (quorum peer) authentication using SASL (Simple Authentication and Security Layer), which provides a layer around Kerberos authentication.
Server to server authentication among ZooKeeper servers in an ensemble mitigates the risk of spoofing by a rogue server on an unsecured network. For more information about quorum peer authentication and how the feature leverages ZooKeeper's SASL support, see the Cloudera Engineering Blog post, Hardening Apache ZooKeeper Security.
Configuring ZooKeeper to use Kerberos for client-server or server-server authentication requires that your organization's Kerberos instance (MIT Kerberos, Microsoft Active Directory) be up and running, and reachable by the ZooKeeper server or client during the configuration processes detailed below.
Before enabling mutual authentication, the ZooKeeper servers in the cluster must be configured to authenticate using Kerberos.
Cloudera recommends that you ensure your ZooKeeper ensemble is working properly, before you attempt to integrate Kerberos authentication.