ONNX Runtime Dies on Alpine: the ld-linux-x86-64.so.2 Error and Why libc6-compat Won't Save You
onnxruntime-node ships prebuilt binaries built against glibc, and libonnxruntime.so.1 carries a DT_NEEDED entry pointing directly at ld-linux-x86-64.so.2 — glibc's own dynamic loader. Alpine uses musl, where that file does not exist, so dlopen fails at the library-loading step. Installing libc6-compat or gcompat does not fix it: they provide the loader file so you clear the first error, then die on the second one, __vsnprintf_chk: symbol not found. The practical answer is to change the base image to node:22-bookworm-slim, paying about 89 MB more for something that actually runs.
At 21:30 I added a Dockerfile for ClubDay — an event web app whose drawing game is scored by an ONNX model running on the server itself. The base image was reflex: node:22-alpine, because it is small.
The image built cleanly. The container came up. docker ps was green. Then, at the moment the server loaded the model, everything collapsed with an error line that never mentions ONNX:
Error loading shared library ld-linux-x86-64.so.2: No such file or directory
(needed by /app/node_modules/onnxruntime-node/bin/napi-v6/linux/x64/libonnxruntime.so.1)
At 21:44 I changed one line in the Dockerfile and everything worked. But the fourteen minutes in between are worth writing down, because that error line names a file you never installed, never declared in package.json, and which is simply always there on your development machine.