I have inherited a failover pair of DHCPD servers running version 3.1.3. They are running just fine but I need to get them to a more supportable, secure and newer version.
I have installed 4.2.3-P1 on a lab server and tested my current dhcpd.conf file with dhcpd -t. It doesn't have any complaints (yet). Moving an existing lease file to the test box for further testing may be problematic.
What is the procedure for upgrading a failover pair? I know the pair is supposed to run the same version but I need to make sure that the first server I upgrade is fully functional before I commit the second server to an upgrade. I can run on one server for a while but I can't have both down at the same time for more than a few minutes .