We use cookies to ensure that we give you the best experience on our website.  Visit our Privacy Policy to learn more. If you continue to use this site, we will assume that you are okay with it.

Your choices regarding cookies on this site.
Your preferences have been updated.
In order for the changes to take effect completely please clear your browser cookies and cache. Then reload the page.

Werk #7326: 'Update DNS cache' action is now really cleaning up the cache

Title"Update DNS cache" action is now really cleaning up the cache
Date2019-03-21 16:03:26
Checkmk EditionCheckmk Raw Edition (CRE)
Checkmk Version1.6.0b1,1.5.0p14
LevelProminent Change
ClassBug Fix
CompatibilityCompatible - no manual interaction needed

As written in the documentation (https://mathias-kettner.com/cms_wato_hosts.html) Check_MK is keeping an internal DNS cache for the hosts that have configured no static IP address in Check_MK:


With the host name method Check_MK uses cached data in order to minimise repeated DNS requests during an Activate Changes – which is very important for accelerating the activation procedure. Furthermore, the cache ensures that a changed configuration can still be activated if the DNS stops working.

The catch is that Check_MK doesn't automatically notice the change to an address in DNS. For this reason, in the host details there is the button which deletes the entire DNS cache and forces a new resolution at the next Activate changes. This file is found under ~/var/check_mk/ipaddresses.cache in your instance, by the way. Deleting this file has the same effect as the button as described above.


The problem was that previous versions did not really delete the entire cache, but only updated it. We have now changed this to make the cache invalidation work as intended.