You need to understand the terms in this section in order to administer KDCs.
The Key Distribution Center or KDC is the component of Kerberos that is responsible for issuing credentials. These credentials are created by using information that is stored in the KDC database. Each realm needs at least two KDCs, a master and at least one slave. All KDCs generate credentials, but only the master KDC handles any changes to the KDC database.
A stash file contains the master key for the KDC. This key is used when a server is rebooted to automatically authenticate the KDC before starting the kadmind and krb5kdc commands. Because this file includes the master key, the file and any backups of the file should be kept secure. The file is created with read-only permissions for root. To keep the file secure, do not change the permissions. If the file is compromised, then the key could be used to access or modify the KDC database.