Werk #20124: Use the configured SNMP backend, or fail
| Component | Checks & agents | ||
| Title | Use the configured SNMP backend, or fail | ||
| Date | Aug 2, 2026 | ||
| Level | Trivial Change | ||
| Class | Bug Fix | ||
| Compatibility | Incompatible - Manual interaction might be required | ||
| Checkmk versions & editions |
|
This werk is only incompatible for users of the community edition who configured the "inline" SNMP backend (which is not available in that edition).
The inline SNMP backend is only shipped in the commercial editions, but nothing stopped you from configuring it anywhere else. If you set it in the global setting Choose SNMP backend, Checkmk quietly used the classic backend instead and wrote an error to the log every time it created a backend. If you set it in the ruleset Hosts using a specific SNMP Backend, the affected hosts failed with "Bad Host SNMP Backend configuration: inline".
Checkmk now uses the backend you configured, or fails: If the configured backend is not available, the Check_MK service of the affected hosts goes CRIT with "The 'Inline' SNMP backend is not available in this installation". No more monitoring your hosts in a way you did not ask for -- and no more crash reports claiming inline SNMP when the classic backend was doing the work.
For that to be a sensible default, the default SNMP backend is now the classic one. The global setting Choose SNMP backend and the ruleset Hosts using a specific SNMP Backend only offer the backends your installation can actually provide.
What you need to do
Nothing, in the editions that ship the inline backend: New sites are set up with it, and sites that never configured a backend explicitly get it written into their configuration during the update. Keep in mind that the shipped default is now the classic backend, so resetting Choose SNMP backend to its default switches that site to the classic backend.
If you run the Checkmk Community Edition and have explicitly configured the inline backend, change the global setting or the rule to the classic backend -- otherwise the affected hosts will go CRIT.
omd update points this out for you: it warns about a configured inline backend that your installation cannot provide.
This also applies if you switch from a commercial edition to the Community Edition:
A configured backend is not silently dropped, it is shown as an invalid choice that you have to correct.