mkdir broken on Docker remote builder using nix

Questions / Help Build debugging
1

This was working fine until recently, I’ve tried previous image tags, and it doesn’t work either.

This simple Dockerfile fails to build now:

FROM nixos/nix

RUN mkdir /app

I thought maybe /app had become protected by Fly or something, but any variant still fails:

FROM nixos/nix

RUN mkdir /blah

Some more notes: running this on a local Docker daemon works fine. Other images work fine:

FROM alpine

RUN mkdir /app

So it’s something specific to this image. I’ve also tried deleting the remote builder and using a new one, but that did not help.

Actual error:

 => ERROR [2/2] RUN mkdir /app                                                                                                        0.4s
------
 > [2/2] RUN mkdir /app:
------
Error failed to fetch an image or build from source: error building: executor failed running [/bin/sh -c mkdir /app]: exit code: 139

Any ideas what’s happening? Thanks for the help.

2

This is almost definitely the same problem: Segmentation fault no matter what i have in my Dockerfile

We’re rolling out updated kernels next week: Fly.io Status - Host kernel upgrades

You can try deleting the remote builder and letting us create you a new one. It’s possible it will end up on a host with an updated kernel, but it’s not something you can control directly.

3

Thanks. I tried a few times but no luck, I guess I’ll wait till the July 19th release.

4

@kurt : confirming the just-completed maintenance seemed to fix this issue.

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