Hey I too recently deployed a rails app, it too has this issue.
tldr; the error is the app fails to open temp files
I investigated further,
I’m getting the error just before when I’m trying to access specific route
Like I have noticed this happed multiple times
2023-06-16T13:03:40Z app[<useful-id>] atl [info]ERROR No such file or directory (os error 2)
2023-06-16T13:03:40Z app[<useful-id>] atl [info]I, [2023-06-16T13:03:40.735309 #521] INFO -- : [86fb280c-08dc-4116-a11c-1120e2095593] Started GET "/route" for <useful-ip>at 2023-06-16 13:03:40 +0000
So I tried to run the app in local and observe the logs
here are the logs that are generated when I try visiting the same route
xdg-open /home/user/app-name/tmp/tmpfile
...<Irrelavent conetens of file>
Started GET "/route" for 127.0.0.1 at 2023-06-16 18:45:25 +0530
and you can google xdg-open is for opening files
so I think its unable to open some temporary files and hence giving the error.
As we can understand most of the functionality does not require /tmp files
which explains why app is running fine
But we get an error while trying to open some non-existent tmp files
which seems the issue as you can google (os error 2) is raised when there is No such file or directory is found.