Werk #22193: multipath: update no longer fails with "non-empty params vanished"
| Component | Checks & agents | ||||
| Title | multipath: update no longer fails with "non-empty params vanished" | ||||
| Date | Oct 22, 2026 | ||||
| Level | Trivial Change | ||||
| Class | Bug Fix | ||||
| Compatibility | Compatible - no manual interaction needed | ||||
| Checkmk versions & editions |
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Since Werk #20113, the service discovery records the number of paths for each Multipath service on Linux hosts. Updating a site where such services had been discovered, or accepted as changed in the service discovery, aborted with:
multipath: Migration failed: params={'discovered_paths': 4} for plug-in 'multipath': non-empty params vanished.
Before an update, Checkmk checks the discovered services against their rulesets. The ruleset Linux and Solaris Multipath Count did not know the recorded number of paths and dropped it, which the update treated as an error. The ruleset now keeps it.
The check uses the code of the version you update to. To recover, update to a version that contains this werk: the update then succeeds without further action, whichever version you start from. This is also the way out for the web-based update, which offers no way to skip the error.
If you updated on the command line and chose to continue past the error, the update removed the affected Multipath services. Run a service discovery on these hosts to add them again.