David Kovacs30 Oct 2026
The Secret File Was Secure. The Application Could Not Read It.
A password file was rendered with strict permissions, but for the wrong owner. The fix preserved confidentiality and restored access only for the a...
Read noteDavid Kovacs · Software developer & architect
Notes from building,
debugging, and learning.
Practical notes on software, systems, and the occasional problem worth writing down.
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15 Oct 2026
The Best Infrastructure Role Is Often the One That Deletes an Exception
A Wazuh ignore rule was correct for one Proxmox node. When a second node needed it, the exception had become a rule that the Ansible role needed to...
Read note08 Oct 2026
Ambient Notifications Should Be Quiet, Specific, and Reversible
A bin-collection reminder needed to be visible in the kitchen without sending another alert, taking over the light, or leaving a stale colour behind.
Read note05 Oct 2026
The Repository Wasn't Driving Anything
A failed package update looked like a TPU driver problem. The USB accelerator was already working; a stale APT source was merely preventing mainten...
Read note24 Sep 2026
The Configuration Was Correct—Until We Restarted It
A service worked because its running configuration had been repaired manually. The next deployment recreated it from a different source of truth.
Read note17 Sep 2026
The Kill Switch Is the Feature, Not the VPN
A Docker stack using Gluetun and two application services needs one important property: the services must have no route when the VPN is unavailable.
Read note10 Sep 2026
When Twenty Low-Battery Alerts Mean One Broken System
A group of battery sensors became unknown at the same time. The batteries were not the problem; the Zigbee integration was.
Read note27 Sep 2022
Update dependencies with Renovate
All projects have dependencies. To manage them is quite difficult. It is also difficult to keep them up to date.
Read note13 Sep 2022
Motivation
My motiviation to start this blog is to learn more about myself and maybe share some knowledge.
Read note07 Sep 2022
Hello World!
Hi, my name is David Kovacs. I thought of starting a blog quite some time ago.
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