detect dns servers when networkmanager is used too, refs #22127

tests/test_dns_records.py

@@ -22,6 +22,11 @@ def get_dns_servers():
         for l in d.split('\n'):
             if l.startswith('nameserver '):
                 servers.append(l.split('nameserver ')[1])
+    if servers == ['127.0.1.1']:
+        # NetworkManager
+        status, output = subprocess.getstatusoutput('grep -R "dns=" /etc/NetworkManager/system-connections')
+        for l in output.split('\n'):
+            servers.extend(l.split('dns=')[1].rstrip(';').split(';'))
     return servers
 
 resolvers = get_dns_servers()