Fixing "Could Not Load Openssl" Mastodon Build Error

While trying to update my Mastodon server to the latest v4.2.0 release, I kept running into build failures when running docker-compose build. I got errors like this in the logs:

#20 27.04 Bundler 2.4.10 is running, but your lockfile was generated with 2.4.13. Installing Bundler 2.4.13 and restarting using that version.
#20 27.21 There was an error installing the locked bundler version (2.4.13), rerun with the `--verbose` flag for more details. Going on using bundler 2.4.10.
#20 27.29 Could not load OpenSSL.
#20 27.29 You must recompile Ruby with OpenSSL support.

It was very confusing since the official CI builds seemed to be working fine. Nevertheless, there were multiple issues opened about this, so it’s something people were running into.

I bisected this build issue to commit https://github.com/mastodon/mastodon/commit/b749de766f5a6158fd0b5f3c3201943083fc7979 which bumps the tag of the Docker node image from Debian bullseye to bookworm.

I dug into it further. I tried to repro the build failure on my desktop, but it works there; it only fails when building on the server on which I run my Mastodon instance.

After more investigation, I found that the hashes of the ruby-jemalloc image used by the build process are different between the server and my local desktop

Server:

[
    {
        "Id": "sha256:c9d180a360e5d39e463cbb202eb10bc4e6d44af3f6ba53fbd26874027aea9ec9",
        "RepoTags": [
            "ghcr.io/moritzheiber/ruby-jemalloc:3.2.2-slim"
        ],
        "RepoDigests": [
            "ghcr.io/moritzheiber/ruby-jemalloc@sha256:9f452d67da4ffdc9abc103015ca447f442d324946a78cefcea9d35f558ce9a93"
        ],
        "Parent": "",
        "Comment": "buildkit.dockerfile.v0",
        "Created": "2023-06-05T07:47:27.743594335Z",

Desktop:

[
    {
        "Id": "sha256:6bebe65ca9cf60a9d55145104943af2493c46a593c36d9ada11f0940db7a280e",
        "RepoTags": [
            "ghcr.io/moritzheiber/ruby-jemalloc:3.2.2-slim"
        ],
        "RepoDigests": [
            "ghcr.io/moritzheiber/ruby-jemalloc@sha256:9a1487af836fada451d706b4b9b4f17a42e82cab5bcef1d77cb577134473f9a6"
        ],
        "Parent": "",
        "Comment": "buildkit.dockerfile.v0",
        "Created": "2023-09-18T09:01:47.627305986Z",

My guess is that whoever maintains that ruby-jemalloc image force-pushed a new version of the package to the same tag. My server has the old version cached, and my desktop picked up the new one.

The Fix⌗

I ran docker image rm ghcr.io/moritzheiber/ruby-jemalloc:3.2.2-slim on the server. This cleared out that old stale ruby-jemalloc image, re-fetched the new one, and fixed my build.

So yeah - there’s a workaround for that @NahNick and @CSDUMMI. The issue isn’t technically on mastodon’s side, and it should go away the next time they upgrade their ruby version (as long as the ruby-jemalloc maintainer doesn’t do this again in the future).

Fixing “Could Not Load Openssl” Mastodon Build Error

The Fix⌗