Check_MK Werk 8124: Avoid configuration changes to be become active without activate changes

ID: 8124 Title: Avoid configuration changes to be become active without activate changes Component: config Level: 2 Class: Bug fix Version: 1.2.7i1 The Check_MK keepalive mode, which is used for the Check_MK helpers and for the RRD creation helper, now uses a new method for reading the configuration from <tt>main.mk</tt>, the other <tt>*.mk</tt> files and the <tt>autochecks</tt>. This new method has two advantages: <ul> <li>Changes done to <tt>*.mk</tt> files can no longer become active unless they are activated. This even holds for core or server restarts and for crashed check helpers</li> <li>Check helpers and RRD helper do not any longer need to restart themselves after a configuration change but simply reload the changed configuration. This has a muss smaller CPU footprint when activating changes.</li> <li>Autochecks files are now only read for the host that is currently being delt with. This makes the internal check table much smaller and speeds configuration reloads.</li> </ul> The gross result is that configuration changes are now really automic and also faster. H2:Implementation details Whenever you create the configuration for the core (options <tt>-B</tt>, <tt>-O</tt>, <tt>-R</tt> or <tt>-U</tt> or <i>Activate Changes</i> via WATO) then the complete configuration (the result from parsing <tt>main.mk</tt> and friends) is written to the file <tt>var/check_mk/core/config.mk</tt>. The core then triggers the check helpers for configuration reload. The helpers simply re-read that file and are immediately up-to-date. At the same time copies (hard links) of the autochecks files in <tt>var/check_mk/autochecks</tt> are being created in <tt>var/check_mk/core/autochecks</tt>. These files are used during the monitoring. Note: The <i>Discovery</i> check (formerly known as <i>Inventory<i> check) does <i>not</i> use the activated configuration but still that one that is modified via WATO. That way after doing a service discovery the discovery check will immediately be happy - without a core restart. This is just as it used to be.