Werk #18917: Agent updater/non-root agent: Stops working after logfile rotation
| Component | Agent bakery | ||||
| Title | Agent updater/non-root agent: Stops working after logfile rotation | ||||
| Date | Oct 21, 2025 | ||||
| Level | Trivial Change | ||||
| Class | Bug Fix | ||||
| Compatibility | Incompatible - Manual interaction might be required | ||||
| Checkmk versions & editions |
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This is a follow-up to Werk #18278.
When using the agent updater together with the non-root agent deployment, agent updates stopped working on cmk-update-agent.log logfile rotation.
Technical background:
Additional to the PID-file - see Werk mentioned above - the two instances of cmk-update-agent also share the same logfile.
The logfile normally gets created by the agent updater running under the non-root user.
After a while the logfile gets rotated, i.e., cmk-update-agent.log is moved to cmk-update-agent.log.1 and a new cmk-update-agent.log is created.
This is normally done by the agent updater running under root, since it's invoked every minute.
However, the new logfile gets created with root ownership, and the non-root agent updater instance can't initialize logging, resulting in a crash.
To unblock agent installations to perform updates again, you can change the ownership of the logfile manually:
chown cmk-agent:cmk-agent /opt/checkmk/agent/default/runtime/cmk-update-agent.log
Please make sure to update the agent soon, since the error would come back after next logfile rotation.