4.1.7 Switching Master and Slave KDCs
You may occasionally want to use one of your slave KDCs as the master.
This might happen if you are upgrading the master KDC, or if your master
KDC has a disk crash.
Assuming you have configured all of your KDCs to be able to function as
either the master KDC or a slave KDC (as this document recommends), all
you need to do to make the changeover is:
If the master KDC is still running, do the following on the old
- Kill the
- Disable the cron job that propagates the database.
- Run your database propagation script manually, to ensure that the slaves
all have the latest copy of the database. (See Propagate the Database to Each Slave KDC.) If there is a need to preserve per-principal
policy information from the database, you should do a “kdb5_util dump
-ov” in order to preserve that information and propogate that dump file
securely by some means to the slave so that its database has the correct
state of the per-principal policy information.
On the new master KDC:
- Create a database keytab. (See Create a kadmind Keytab (optional).)
- Start the
kadmind daemon. (See Start the Kerberos Daemons.)
- Set up the cron job to propagate the database. (See Propagate the Database to Each Slave KDC.)
- Switch the CNAMEs of the old and new master KDCs. (If you don't do
this, you'll need to change the
krb5.conf file on every client
machine in your Kerberos realm.)