Werk #6446: Fixed changing agent type from "No agent" to agent in some cases

Component Setup
Title Fixed changing agent type from "No agent" to agent in some cases
Date Aug 13, 2018
Checkmk Edition Checkmk Raw (CRE)
Checkmk Version 1.5.0p2 1.6.0b1
Level Prominent Change
Class Bug Fix
Compatibility Compatible - no manual interaction needed

With werk #5535 we changed the tag group "Agent type" to be a builtin tag group. When a pre-1.5 site modified this tag group before updating to 1.5, this tag group was left untouched.

In this situation hosts that were marked as "No agent" (ping only hosts) were suddenly set to "Check_MK Agent (Server)" which resulted in error messages in the monitoring after activating the configuration, because these hosts got a Check_MK service and tried to contact the agent while there is none on the affected hosts.

We have now changed the migration logic to extend the locally modified "Agent type" tag group with the options Check_MK 1.5 needs. This change should make your "No agent" hosts now stick with the intended configuration.

In case you are affected by this issue, you may notice that the choices of the "Agent type" are now extended with some new options which may be confusing in the first moment. You can now navigate to the "Host tags" page in WATO and edit the tag group "agent" to sort the new options according to your needs.

The tag choices in the tag group "Agent type" that are available in your site after the update (that are not part of the 1.5 standard) are displayed with the "Legacy: " prefix. This can be useful in the moment you want to clean them up.

To migrate the legacy choices you need to clean up all objects referring these choices before they can safely be removed. Examples:

  • The legacy "No Agent" choice was using the Tag ID "ping". The new one uses the "no-agent" tag ID. You can now delete the legacy choice from the tag group and hit save. The GUI will then inform you about all hosts, folders or rulesets using this tag choice. Navigate to all objects and change the old setting to the new one. After that you can safely remove the legacy choice.
  • For the snmp-only, snmp-v1 and snmp-tcp options it's a bit more complicated because it involves now two tag groups (SNMP + Agent type). To use the new scheme you need to set the configuration like this:
    • snmp-only: Agent type = "No agent" and SNMP = SNMP v2 or v3
    • snmp-v1: Agent type = "No agent" and SNMP = SNMP v1
    • snmp-tcp: Agent type = "Contact either Check_MK Agent or use datasource program" and SNMP = SNMP v2 or v3

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