Pnp4nagios templates

General
1

Hi,

I am trying to improve some pnp graphs for some builtin checks and nagios plugins and local checks, but I am a bit confused, I am wondering how check-mk-raw creates the pnp graphs using rrdtools? I found several locations for the php templates:

  1. /omd/versions/1.6.0p6.cre/share/check_mk/pnp-templates/
  2. /omd/versions/1.6.0p6.cre/share/pnp4nagios/htdocs/templates.dist/
  3. /omd/sites/ {sitename} /etc/pnp4nagios/templates/

So I have several questions please:

  1. How are the php files related in these directories?
  2. are the builtin checks located at /opt/omd/versions/1.6.0p6.cre/share/check_mk/checks/ or at /opt/omd/sites/ {sitename} /share/check_mk/checks/ ? and how are they related (obviously they are the same)?
  3. Which templates are usedto create the graphs for the builtin checks?
  4. Which templates are usedto create the graphs for the nagios plugins?
  5. Which templates are used to create the graphs for local checks?

Beside that I would like to know:

  1. how does check-mk knows which template is to be used for which check? (where is it implemented)
  2. Is it OK to modify builtin checks according to my needs? if yes which ones? those in /omd/sites or /omd/versions?
  3. Is it OK to modify builtin templates according to my needs? if yes which ones? those in pnp-templates or in templates.dist? or is it better to create a new check and template? and where to place them (checks as well as templates)?

I appreciate any help on this, a link to the documentation will be helpful as well.

Thanks a lot.