fixed ext_pillar according to https://docs.saltstack.com/en/latest/topics/development/external_pillars.html#configuration and master_tops according to https://docs.saltstack.com/en/latest/topics/master_tops/index.html

salt/files/master.d/f_defaults.conf

 # master_tops:
 #   ext_nodes: <Shell command which returns yaml>
 #
-{{ get_config('master_tops', '{}') }}
+{% if 'master_tops' in cfg_master %}
+master_tops:
+{%- for master in cfg_master['master_tops'] -%}
+  {%- if cfg_master['master_tops'][master] is string %}
+  {{ master }}: {{ cfg_master['master_tops'][master] }}
+  {%- else %}
+  {{ master}}:
+    {%- for parameter in cfg_master['master_tops'][master] %}
+    {{ parameter }}: {{ cfg_master['master_tops'][master][parameter] }}
+    {%- endfor -%}
+  {%- endif -%}
+{%- endfor %}
+{% endif %}
 
 # The external_nodes option allows Salt to gather data that would normally be
 # placed in a top file. The external_nodes option is the executable that will
 #
 {% if 'ext_pillar' in cfg_master %}
 ext_pillar:
-{% for pillar in cfg_master['ext_pillar'] %}
-  - {{ pillar.items()[0][0] }}: {{ pillar.items()[0][1] }}
-{% endfor %}
+{%- for pillar in cfg_master['ext_pillar'] -%}
+  {%- for key in pillar -%}
+    {%- if pillar[key] is string %}
+  - {{ key }}: {{ pillar[key] }}
+    {%- elif pillar[key] is iterable and pillar[key] is not mapping %}
+  - {{ key }}:
+      {%- for parameter in pillar[key] %}
+    - {{ parameter }}
+      {%- endfor -%}
+    {%- elif pillar[key] is mapping and pillar[key] is not string %}
+  - {{ key }}: 
+      {%- for parameter in pillar[key] %}
+      {{ parameter }}: {{pillar[key][parameter]}}
+      {%- endfor %}
+    {%- else %}
+# Error in rendering {{ key }}, please read https://docs.saltstack.com/en/latest/topics/development/external_pillars.html#configuration
+    {% endif %}
+  {%- endfor -%}
+{%- endfor %}
 {% elif 'ext_pillar' in cfg_salt %}
 ext_pillar:
 {% for pillar in cfg_salt['ext_pillar'] %}