Increasing Log Level for dhcp6 and systemd

[Rynhart, Patrick]

We're seeing lots of these messages in our systemd logs as follows:

# journalctl -u dhcpd6 -f

Sep 12 09:30:49  dhcpd[51155]: Unable to pick client address: no IPv6 
pools on this shared network
Sep 12 09:30:49  dhcpd[51155]: Unable to pick client address: no IPv6 
pools on this shared network
Sep 12 09:30:49  dhcpd[51155]: Unable to pick client address: no IPv6 
pools on this shared network
Sep 12 09:30:49  dhcpd[51155]: Unable to pick client address: no IPv6 
pools on this shared network
Sep 12 09:30:49  dhcpd[51155]: Unable to pick client address: no IPv6 
pools on this shared network
Sep 12 09:30:49  dhcpd[51155]: Unable to pick client address: no IPv6 
pools on this shared network

.........

What we want to be able to do is to identify the relevant client(s) and 
shared networks.  We have a large number of shared networks:

# grep subnet6 networks6 | wc -l
163

The version of ISC dhcpd that we're running is

# /usr/sbin/dhcpd -V
Internet Systems Consortium DHCP Server 4.3.5

All the posts that we can find online seem to be for the trivial case of 
a single shared network.  Can someone please tell us how to increase the 
verbosity (while under systemd logging) - or otherwise get debug 
information which will allow us to identify the affected clients & networks.

With Thanks,

Patrick

Patrick Rynhart

Systems Engineer, Massey University (New Zealand)