#9 Define ErrorLogFormat for apache behind haproxy

templates/etc-apache2-conf-available-global-redirect

@@ -14,3 +14,7 @@ RewriteCond %{HTTP_REFERER} ^([^.]+.)*dummy\.referer [NC]
 RewriteRule .* - [F,L]
 
 RequestHeader unset Proxy early
+
+{% if groups.proxyserver is defined %}
+ErrorLogFormat "[%{u}t] [%m:%l] [pid %P] [client %{X-Forwarded-For}i] %M"
+{% endif %}