Post B2F29ErQSxmoaU6sxk by hanno@mastodon.social
 (DIR) More posts by hanno@mastodon.social
 (DIR) Post #B2F291R4Ndymwyg9Zo by hanno@mastodon.social
       2026-01-13T11:14:23Z
       
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       Mysterious bug from hell: I noticed that a Docker container running an Apache web server was sometimes shutting down for no apparent reason, but rarely enough that it was difficult to reproduce. After adding some debugging (given this shuts down the container there was no way to access the logs afterwards easily) and waiting for the issue to show up again.🧵
       
 (DIR) Post #B2F2930YXBxXpKI0Wm by hanno@mastodon.social
       2026-01-13T11:15:52Z
       
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       Today, the issue showed up again, this time with my debugging code showing me the logfiles before shuttiing down the container:"AH00170: caught SIGWINCH, shutting down gracefully"What is SIGWINCH? It is a signal for "window change", aka, I resized the terminal window. Ok... that makes some sense that I would observe this occasionally, but not reproducibly, and resizing a terminal is certainly not something I had expected as the cause. But... why?
       
 (DIR) Post #B2F298u2cKJU6rHtCq by hanno@mastodon.social
       2026-01-13T11:18:00Z
       
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       I mean, why does apache,  A WEB SERVER THAT SHOULD NOT DISPLAY MUCH ON THE TERMINAL AND CERTAINLY HAS NO GUI TO REDRAW, care when I resize my terminal?Turns out, as you can read here https://stackoverflow.com/a/787509/3780436 or in their bug tracker (however, they locked down their bugtracker and you cannot even read it without registration) that, apparently, apache decided to reuse the SIGWINCH signal as you usually don't run apache in the foreground...
       
 (DIR) Post #B2F29ErQSxmoaU6sxk by hanno@mastodon.social
       2026-01-13T11:21:19Z
       
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       I guess there's some way to workaround this... just have to figure out how.But... certainly unexpected, and given that "run thing in the foreground in your container" is pretty common stuff these days, maybe Apache should reconsider that decision...
       
 (DIR) Post #B2F29KiQhK9gkJwmm0 by hanno@mastodon.social
       2026-01-13T11:25:30Z
       
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       For what it's worth: this also happens with the official Dockerhub httpd image...So I guess they haven't found a workaround yet either...
       
 (DIR) Post #B2F29QNjdBAOJsJLLk by hanno@mastodon.social
       2026-01-13T11:37:48Z
       
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       Reported: https://github.com/docker-library/httpd/issues/280