Category Archives: Technical

“Rational” IT related entries.

Datadog: nginx access.log / error.log permission denied

Problem:

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Datadog: “could not retrieve nginx version info”

Apparently Datadog fails to retrieve nginx version information when server_tokens directive in nginx configuration is set to off.

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Refresh web-browser without leaving VS Code

I’ve created an extension for VS Code which lets you refresh your web-browser (Safari or Chrome) by pressing Cmd-R without leaving VS Code. Meet Refresh Browser (GitHub).

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Apache Guacamole: RDP printer not working, “error parsing HTTP request header”, “Invalid character found” etc

If you’re using Apache Guacamole 1.0.0 behind an nginx reverse proxy, and Guacamole’s RDP printer doesn’t work, and browser console logs error 400, welcome to read further.

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Apache Guacamole: how to change the default URL path (/guacamole) to something else

Say you want to change Apache Guacamole’s URL from http://server:8080/guacamole to something like http://server:8080/my-hidden-guacamole-instance (or perhaps you’re using nginx to proxy requests to Guacamole / Tomcat and you don’t want any path at all).

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macOS High Sierra: Spotlight search not working — “Database mapping failed” error spammed to the system log

Solution can be found here (read the post that starts from “I’ve solved this…” by Design Complex).

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macOS High Sierra doesn’t start after updating (stuck on Apple logo) — “failed to unwrap volume key” error

The first thing you want to do when your Mac system doesn’t start is to start up into the verbose mode to see if there any error messages. Don’t try to fix the problem before diagnosing!

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Windows Server 2019: RD Session Host — ChangeMode “Invalid operation” exception

If you’re changing the client access licensing mode of your RD Session Host using the PowerShell $obj.ChangeMode(…) command and it fails with an error saying “Exception … Invalid operation”…

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“Install %OS%.app does not appear to be a valid OS installer application” (createinstallmedia error)

If you’re trying to create a bootable installer for an older macOS version (like El Capitan) with createinstallmedia, and it fails with a “does not appear to be a valid OS installer” error, quite possible the actual problem is that … Continue reading

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Downgrade any Homebrew package easily

I’ll use Tesseract as an example, but the same logic can be applied to any other Homebrew package.

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