Docker exec user process caused: no such file or directory means runc got all the way to the last step of container startup, called exec on your entrypoint, and the kernel answered that the target does not exist. The file you are staring at is almost always present; what is absent is the interpreter named on its shebang line, or the dynamic loader the binary asks the kernel for.

Four fragments, three different producers, one line. Only "exec user process" is a literal anyone wrote.

What this error means

A container dies the instant it starts, in a job where the build was green, and the message names a Go source file and a line number that have nothing to do with your code. The line number moves between reports of the same failure, which is the first clue about how the text is made: two public issues quote this failure at standard_init_linux.go:219 and at standard_init_linux.go:211 and neither number means anything you can look up.…