After upgrade to 2.4.0p8, connection tests fail with "API Error:Error running automation call"

Troubleshooting
,
1

CMK version: 2.4.0p8
OS version: Rocky Linux 9.5

Error message: API Error:Error running automation call diag-host: 404 Client Error: Not Found for url: http://local-automation/automation

after upgrading 2.3.0p34 → 2.4.0p8 (latest) I encounter this error on all monitored nodes:

save & run connection tests:

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cmd-line checks:

cmk -D lnzrunner01

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or cmk -nv lnzrunner01

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or cmk -d lnzrunner01

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so basically it looks good on the cmd-line, but not in the mgmt-interface.

or doing a bulk-discovery shows:

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the webserver log reveals:

$ tail -f var/log/web.log
...
2025-07-24 14:29:31,849 [40] [cmk.web 1040517] Failed to start bulk discovery
Traceback (most recent call last):
  File "/omd/sites/SAL/lib/python3/cmk/gui/wato/pages/bulk_discovery.py", line 138, in action
    raise result.error
cmk.gui.job_scheduler_client.StartupError: Got response: HTTP 404: {"detail":"Not Found"}

I raised a similiar topic in april this year Can't activate changes, or bake a agent after upgrade to 2.4.0p4 and still have no clue what’s going on.

So what is fine in 2.3.0p34 does not work in 2.4.0p8 .
There must be a significant change in this release which I’m not aware of…

2

I’ve been noticed about a werk change Werk #18305: Avoid "HTTP 404: {"detail":"Not Found"}" in Checkmk UI and REST API which will be published within the next release

3

Yes, this is the change which fixes this exact problem. If you want to test this, you can try one of our daily build.

4

Hi , i am facing an issue where i am not sure if i can yes node_exporter directly with cmk or i need a prometheus server. kindly look at my post Integarting prometheus (node-exporter) with checkmk