how to upgrade the failover pair?

Aleksey Perov a.perov at
Thu May 31 07:14:47 UTC 2018


I have two servers running Debian 6.0.5 with ISC DHCP 4.1.1 in a 
failover pair. Now I need to upgrade them to the latest Debian 9 which 
is shipped with ISC DHCP 4.3.5. Since Debian 6 is too old, the only way 
of upgrading is a clean reinstall (which in most cases is better than 
sequential upgrade 6 to 7 to 8 to 9).

I have read 
and some other articles, but those documents say nothing about the 
upgrade scenario.

So the question is: What is the recommended process of _upgrading_ the 
failover pair?

The draft plan is as follows:

- stop the secondary;
- turn the primary into partner-down;
- reinstall the secondary;
- wait until the primary reclaims all addresses in all pools;
- stop the primary;
- copy leases file from primary to secondary;
- start the secondary in partner-down mode;
- reinstall the primary;
- turn the secondary into normal mode;
- start the primary.

Is anything wrong here?

Any advices and recommendations are welcome. Thanks.


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