@Donovan_Cotter Hi, thanks for reaching out!
This is indeed unexpected. I used the Dockerfile excerpt you provided here and did not run into any issues loading the crypt_shared library. Also, Ubuntu 22.04 uses glibc 2.35, which should be just fine for this use case.
Chances are that something else is happening here as part of your docker container setup that’s not part of the Dockerfile that you shared here, and that, whatever it is, it is overwriting your glibc with an older version for some reason. (You can verify this by manually invoking /lib/x86_64-linux-gnu/libc.so.6 as a shell command.)
You should probably try to identify what that is, since it may not just affect the crypt_shared library, but also other parts of your container.
All that being said, if you’re really just looking for a quick and dirty solution, you may be able to just use the crypt_shared library for another Linux distribution with a low glibc requirement (e.g. RHEL7). While we don’t generally recommend using components that were built for other distributions than the one that is actually in use, there’s nothing that should keep it from working if you need it to.