Just started working with Elixir a month or so ago and am trying to package an application in Docker for the first time. It builds perfectly fine, but it crashes when ran with the following error:
/opt/sergei/releases/0.1.0/../../erts-13.1.3/bin/erl: exec: line 12: /opt/sergei/erts-13.1.3/bin/erlexec: not found
I’ve shelled into the docker container; the file does exist.
Here’s my Dockerfile
FROM elixir:alpine AS build_stage
ENV MIX_ENV prod
COPY mix.* ./
COPY config ./config
RUN mix local.hex --force && \
mix local.rebar --force && \
mix deps.get --only prod && \
# Build project
COPY . .
RUN mix release sergei
COPY --from=build_stage /opt/build/_build/prod/rel/sergei /opt/sergei
I did some work to reproduce this locally and while I can’t prove it exactly, I’m willing to bet that there’s a versioning difference between
alpine:latest. If I change the second
FROM statement to
elixir:alpine, it works fine. I’ll do some more digging (because I’m curious), but that seems like a plausible reason to me. Not sure why you’re getting a “no such file or directory” error, though.
I think I know the problem here.
musl OOTB, while most others use
glibc. I cannot reproduce your problem exactly (the only way I was able to do so was by setting the
build_stage FROM to
elixir, which is actually Debian based), however, in that situation, I was able to do some poking. If I
erlexec – since as you point out, it does exist – I see the following
execve("/opt/elixir_hello_world/erts-13.1.4/bin/erlexec", ["/opt/elixir_hello_world/erts-13."...], 0x7ffd6d09ac30 /* 6 vars */) = -1 ENOENT (No such file or directory)
Looking at the man page for
execve, ENOENT can actually be returned under two situations. One, if the executable doesn’t exist, or two, if the loader doesn’t exist for that ELF binary (see here c - execve file not found when stracing the very same file! - Stack Overflow).
What I suspect is going on (but is hard to pin down given I can’t fully recreate your problem) is that
glibc is being brought into your container somehow (are you perhaps copying
_build from your local machine when you build the release? it may be worth adding that to
.dockerignore), which is causing you problems when you move onto a glibc-less system (i.e.
alpine:latest). When I build the release on
elixir:alpine, I see that
erlexec is correctly linked to
/opt/elixir_hello_world/erts-13.1.4/bin # ldd erlexec
libc.musl-x86_64.so.1 => /lib/ld-musl-x86_64.so.1 (0x7faa179c8000)
This was the issue, thank you so much!
Running into the same issue. The app builds in alpine, but when I move it to ubi (redhat) docker image I get
line 12: /opt/sergei/erts-13.1.3/bin/erlexec: not found
I compiled and installed musl libc so it’s resolved correctly:
bash-5.1# ldd /opt/app/rel/logflare/erts-13.2.2/bin/erlexec
libc.musl-x86_64.so.1 => /lib64/libc.musl-x86_64.so.1 (0x00007f7117dcf000)
There is no “_build” directory, but the issue is still there. I even tried copying the library from the alpine container, but that did not do anything.
Host machine is Ubuntu 22.04.
The original answer seems to suggest that it’s due to incompatible binary format. I don’t understand how the alpine based container works, but the UBI9 one doesn’t ?
After some research, it appears that the alpine binaries are just not compatible with not alpine distros. I switched to compiling the app from source using elixir:latest (and updating node and npm) instead of trying to copy the compiled app from the alpine image.
This seems to have solved the problem.