Werk #5397: Microcore can now be configured to send UNREACHABLE notifications

Component	Core & setup
Title	Microcore can now be configured to send UNREACHABLE notifications
Date	Oct 17, 2017
Level	Prominent Change
Class	New Feature
Compatibility	Compatible - no manual interaction needed
Checkmk versions & editions	1.5.0i1 Not yet released Checkmk Enterprise (CEE), Checkmk MSP (CME) 1.5.0i1 Not yet released Checkmk Enterprise (CEE), Checkmk MSP (CME) 1.5.0i1 Not yet released Checkmk Enterprise (CEE), Checkmk MSP (CME) 1.5.0i1 Not yet released Checkmk Enterprise (CEE), Checkmk MSP (CME) 1.5.0i1 Not yet released Checkmk Enterprise (CEE), Checkmk MSP (CME) 1.5.0i1 Not yet released Checkmk Enterprise (CEE), Checkmk MSP (CME) 1.5.0i1 Checkmk Enterprise (CEE), Checkmk MSP (CME)

Normally you don't want to receive UNREACHABLE notifications of hosts. Configuring client/parent relationships between your hosts is a good idea to be able to detect network outages. DOWN states of hosts will then be translated into UNREACHABLE, making your view clear for the real cause (e.g. a router in DOWN state).

But there may be situations where you want to be able to receive these UNREACHABLE notifications. This was already configurable when using the Nagios core for a long time. For the Microcore the suppression of UNREACHABLE notifications was hard coded. This has been changed now.

The default behaviour will not be changed. New sites or updates sites will not send out UNREACHABLE notifications by default. To enable the new feature, you will first have to tell the core to send out UNREACHABLE notifications.

To have a seamless transition we additionally changed these things:

• A default rule that disables the UNREACHABLE notifications is being created for new sites in the ruleset "Notified events for hosts". Whenever you want to enable UNREACHABLE notifications, simply enable them using this rule.
• Updated sites:
  • If you have configured rules for all your hosts in the "Notified events for hosts" ruleset, the core will continue working as configured.
  • Microcore: For hosts that have no matching rule in "Notified events for hosts", the Microcore will not send out UNREACHABLE notifications.
  • Microcore: If you previously had configured a rule in "Notified events for hosts" which enabled the UNREACHABLE notifications, this rule had no effect. It will now be working after updating.
  • Nagios: For hosts that have no matching rule in "Notified events for hosts", the Nagios core will send out UNREACHABLE notifications.

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