Clarification on PARTNER-DOWN and MCLT

[Ian Anderson]

I need some clarification on a few questions.  I am using DHCP 3.0.4 in
a load balance setup.  One of our admins was running a yum-update on the
primary which accidentally installs dhcp 3.0.1 overiting 3.0.4.  When he
restarted dhcpd 3.0.1 obviously it caused some problems.  To correct
this problem he stopped dhcp, installed 3.0.4 and deleted the
dhcpd.lease file.  
 

When the primary was started again it requested a copy of the
dhcpd.leases file from the secondary.  After this was complete the
primary went into a recover-wait mode.

 

We took this time to watch how the server reacts when in a recover-wait
and partner-down mode.  From what I witnessed the server in partner-down
(secondary) was handing out leases while the primary was down.  The
lease time was set to the MCLT (30 minutes). Once we started the primary
again the server went into a recover-wait mode while it waited for the
MCLT to expire.  Once 30 minutes passed both servers returned to a
normal state.  

 

The MCLT is used as a lease time to ensure that clients continually
check in, to check the lease time.  One thing I did not get a chance to
witness is what is the lease time set to when the primary server is in
recover-wait mode?  I would think the secondary server would resume
issuing leases with the dhcpd.conf lease time.  Otherwise what would be
the point of the primary waiting for MCLT to expire if the secondary is
still handing out addresses with the MCLT as the lease time?  

 

Is the MCLT even relevant when the primary server is truly down and not
handing out addresses i.e. not just out of contact with the secondary?

 

Thanks for your time.