OP#490 update README

README.md

@@ -20,6 +20,7 @@
     - [Adding time periods](#adding-time-periods)
     - [Adding custom commands](#adding-custom-commands)
     - [Adding templates](#adding-templates)
+    - [Customization outside of Puppet](#customization-outside-of-puppet)
   - [PuppetDB](#puppetdb)
   - [SELINUX](#selinux)
   - [Support](#support)
@@ -48,6 +49,7 @@ At this stage, the module is being redeveloped and being built to the latest sta
 - configures all required directories for server and clients and sets proper permissions and selinux contexts
 - configures the main nagios configuration file and sets values as (pre)configured per values in params, which can be overwritten.
 - if `ng_include_nrpe`is set to `true`, the confdroid_nrpe module is automatically applied on clients ([confdroid_nrpe](https://sourcecode.confdroid.com/confdroid/confdroid_nrpe) must be in the catalogue then)
+- if `ng_enable_fail2ban`is set to `true`, a fail2ban jail and filter will be added for the Nagios service (requires confdroid_fail2ban).
 
 ## Repo Documentation
 
@@ -293,6 +295,11 @@ In order to add time periods, address the define `confdroid_nagios::nagios::obje
   }
 ```
 
+### Customization outside of Puppet
+
+> Q: what if I want to add my own Nagios plugins, settings etc. outside of Puppet? Will those be overwritten?
+A: Puppet only controls what it knows about. You can add your own custom configuration files within `/etc/nagios/conf.d` and Nagios should recognize it, assuming it is valid code. Just beware of duplicated definitions, Nagios is very strict and merciless about this.
+
 ## PuppetDB
 
 A working instance of PuppetDB connected to the Puppet master is required for this to work. Installation and configuration of PuppetDB is out of scope for this module, however [cd_puppetdb](https://gitlab.confdroid.com/puppet/cd_puppetdb) is available to automate this task for you as well within a few minutes.