Description of problem:

It's impossible to change the SNMP agentaddress via Director:

/etc/puppet/modules/tripleo/manifests/profile/base/snmp.pp
~~~
  if $step >= 4 {
    snmp::snmpv3_user { $snmpd_user:
      authtype => 'MD5',
      authpass => $snmpd_password,
    }
    class { '::snmp':
      agentaddress => ['udp:161','udp6:[::1]:161'],
      snmpd_config => [ join(['createUser ', $snmpd_user, ' MD5 "', $snmpd_password, '"']),
                        join(['rouser ', $snmpd_user]),
                        'proc  cron',
                        'includeAllDisks  10%',
                        'master agentx',
                        'trapsink localhost public',
                        'iquerySecName internalUser',
                        'rouser internalUser',
                        'defaultMonitors yes',
                        'linkUpDownNotifications yes' ],
    }

~~~

Additional info:
I wanted to create a KCS with instructions similar to this - but unfortunately, it is not possible to overwrite the snmpd settings with templates due to the above code.

### Modifying values via puppet ###
Not all values can be changed via `snmpd.local.conf` ; in this case, one can leverage [puppet hiera data](https://access.redhat.com/solutions/2328671)

#### Changing bind / listen address ####
The snmpd listen address is determined by `agentaddress`. This value may only appear once in the configuration, and hence may not appear in both `snmpd.conf` and `snmpd.local.conf` at the same time.
~~~
[root@overcloud-controller-0 ~]# grep agentaddress /etc/snmp/* -R
/etc/snmp/snmpd.conf:agentaddress udp:161,udp6:[::1]:161
~~~

In order to change this value:
~~~
parameter_defaults:
  ExtraConfig:
    snmp::agentaddress: '[ udp:127.0.0.1:161, udp6:[::1]:161 ]
~~~