Keep regex as default but still allow overrides.

_modules/linux_netlink.py

+# -*- coding: utf-8 -*-
+
+import re
+
+
+def ls(regex=r'^[a-z0-9]+$'):
+    """
+    Provide a list of network interfaces.
+    """
+    _lo_re = re.compile(r'^lo$')
+    _alphanum_re = re.compile(regex)
+
+    def _filter(interface):
+        return _alphanum_re.match(interface) and not _lo_re.match(interface)
+
+    return filter(_filter, __salt__['grains.get']('ip_interfaces', {}).keys())

linux/map.jinja

             'crit': '5%',
         },
         'netlink': {
-            'interfaces': ['all'],
+            'interface_override': False,
+            'interfaces': [],
+            'interface_regex': '^[a-z0-9]+$',
             'ignore_selected': False,
         },
     },

linux/meta/collectd.yml

     plugin: netlink
     template: linux/files/collectd_netlink.conf
     ignore_selected: {{ monitoring.netlink.ignore_selected }}
+    {%- if monitoring.netlink.interface_override and monitoring.netlink.interfaces is list %}
+    {%- set interfaces = monitoring.netlink.interfaces %}
+    {%- else %}
+    {%- set interfaces = salt['linux_netlink.ls'](monitoring.netlink.interface_regex) %}
+    {%- endif %} 
+    {%- if interfaces %}
     interfaces:
-    {%- for interface_name in monitoring.netlink.interfaces|sort %}
+    {%- for interface_name in interfaces|sort %}
     - {{ interface_name }}
     {%- endfor %}
     {%- endif %}