prometheus-server: Only target node_exporter for Linux nodes

Signed-off-by: Maximilian Wilhelm <max@sdn.clinic>

prometheus-server/prometheus.yml

@@ -31,7 +31,7 @@ scrape_configs:
   - job_name: node
     static_configs:
       - targets:
-{%- for node, node_config in nodes %}
+{%- for node, node_config in nodes if node_config.get('platform') == 'linux' %}
         - {{ node }}:9100
 {%- endfor %}