I think it would be useful to quantify what’s happening here as well.
- Currently rustc is compiled in a CentOS 5 container which uses glibc 2.5
- However, the actual glibc version required ends up being 2.3.4
- A CentOS 6 container uses glibc 2.12
- A recent survey shows that nothing may be using glibc between 2.5 and 2.12
If you believe that you require an old version of glibc, then it’d be great if you could run ldd --version locally. If it is 2.12 or after then you’re guaranteed to be ok if we move to CentOS 6. If you’re before 2.12 then you may break if we move to CentOS 6.
Note that if we compile against glibc 2.12 the resulting binary may not actually require glibc 2.12. Depending on what symbols end up being linked we may still only require 2.3.4. We should test to see what happens, but I would regardless not want to silently rely on building against glibc 2.12 and just happening to continue to require glibc 2.3.4.