Upgrade from 3.1.0 to 4.1.1

[Glenn Satchell]

Abu Abdulla alhanbali wrote:
> Hi,
> 
> I'm upgrading my DHCP servers (failover pair) from 3.1.0 to a newer 
> version 4.1.1, I want to check some points:
> 
> - Can I compile the newer version while running the current server (to 
> reduce the outage time).

No problem to compile while it's running. If you install the new binary 
over the top of the running executable there may be problems. Not sure 
what your policy is, but I always install into a version-specific 
directory, then symlink to common directory. Otherwise shutdown the old 
one, install and then start.

> - My upgrade procedure will be as follow:
>    - Stop the secondary server and copy the lease file
>    - Start the new version in the secondary while the primary is still 
> running with the old version. i think the failover protocol is still the 
> same in these two versions.
>    - Stop the primary server and restart it again with the new version.

Probably safer to stop both servers, then start the new versions. I've 
always been wary of running different versions of the server in 
failover, even when they allegedly use the same protocol. There are a 
lot of bug fixes between 3.1.0 and 4.1.1.

> another question, i tried to run two instances using different 
> local-port (in the dhcpd.conf) on the same interface but failed. is 
> there a way to run two servers on the same interface IP on different UDP 
> port?

The raw sockets interface means you can't have two dhcpd processes on 
the same interface. If you compile with USE_SOCKETS (and the limitations 
that currently come with that) then you should be able to do it.

Also use the new binary with -t and -T to test dhcpd.conf and dhcpd.leases.

-- 
regards,
-glenn