1. Introduction

For the problems DOWN, UNREACH, WARN, CRIT or UNKNOWN Checkmk distinguishes two possible states: unhandled and icon ack handled. A handled (acknowledged) problem indicates that the issue is known and that somebody is attending to it.

If a problem has been acknowledged, then…​

  • …​ it will be identified with a icon ack icon,

  • …​ it will no longer appear as Unhandled in the Overview snap-in,

  • …​ no further notifications will be sent.

Additionally, problems can be systematically identified in views as being acknowledged or unacknowledged via the Icon for displaying the filter bar. filter Problem acknowledged.

2. The acknowledgement procedure

Problems are acknowledged via commands on the affected hosts/services. Acknowledgements can be removed in the same way.

basics ackn acknowledge

Advice for these options:


You can include a URL such as in this field, which will be replaced by a clickable link.

Expire on

Commercial editions: With this option you can set a validity period for the acknowledgement. When the specified time has been reached, the acknowledgement is automatically deleted, even if the host/service does not go back to OK or UP.

Ignore status changes until services/hosts are OK/UP again (sticky)

An acknowledgement is normally valid until the next change. If for example, a service has been acknowledged with a WARN status, and later changes to CRIT, the acknowledgement will be automatically-removed. Activating this option will retain the acknowledgement until the OK or UP status is reached.

Keep comment after acknowledgment expires (persistent comment)

With this option your comment will not be automatically deleted if the acknowledgement disappears or is removed. Comments created in this way must be deleted manually later as described in the next chapter.

Notify affected users if notification rules are in place (send notifications)

Triggers notifications of type ACKNOWLEDGEMENT to all contacts of the host/service . So your colleagues know about it.

You can permanently change the default settings for these options via Edit defaults. These settings are also available via Setup > General > Global settings > User interface > Acknowledge problems.

3. Acknowledgements in the GUI

In the Checkmk web interface there are several possibilities for displaying acknowledgements.

In all host and service views, acknowledged problems are identified by two icons:

icon ack

This icon identifies an acknowledgement

icon comment

Clicking on this icon displays a list with any acknowledgement comments.

Via Monitor > Overview > Comments you can view a list of all comments for hosts and services — including those created through acknowledgements. Comments may be deleted with commands.

basics ackn comments
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