httpd container unexpectedly stops when resizing terminal window

[hannob]

When one starts the container and resizes the terminal window, it suddenly stops.

To reproduce:

docker run httpd:latest
[...]
[resizing window]
[Tue Jan 13 11:25:11.623227 2026] [core:notice] [pid 1:tid 1] AH00094: Command line: 'httpd -D FOREGROUND'
[Tue Jan 13 11:25:13.981184 2026] [mpm_event:notice] [pid 1:tid 1] AH00492: caught SIGWINCH, shutting down gracefully

The reason, it appears, is that resizing a terminal causes a SIGWINCH signal, and Apache httpd has decided to reuse that signal as a "graceful server shutdown" signal. See also:
https://stackoverflow.com/a/32647166/3780436
https://httpd.apache.org/docs/2.2/stopping.html#gracefulstop
https://bz.apache.org/bugzilla/show_bug.cgi?id=50669

The latter link is their bugtracker, which, unfortunately, is only accessible with an account. But the bug has been closed as "WONTFIX". (Comment from Apache dev in 2011: "You are correct that SIGWINCH is used to signal a windows size change to the applications running on a terminal. Due to the lack of other signal numbers and given the fact that httpd normally runs detached from a terminal the SIGWINCH signal was chosen to instruct httpd to do a graceful shutdown. So this works as designed.")

I think this is a poor design decision by Apache httpd, but, apparently, intentional. But I will also add a comment that, maybe, in 2026 this is an issue to be seen differently.

[yosifkit]

Unfortunately, this is upstream behavior. Anything we add would be a workaround at best (and extra custom code to maintain). Perhaps upstream would now be open to changing it, but perhaps not.

For the Docker use case, the solution is to not run the httpd image interactively or even attached and only run it detached (docker run -d --name httpd httpd:latest). In non-detached mode, docker/the terminal tty still sends signals like SIGWINCH.