Like, seriously. It's impossible to run Erlang/OTP 21.0 on a modern Ubuntu/Debian because of libssl/glibc shenanigans so your best bet is to take a container with the userspace of Ubuntu 16 (which somehow works just fine on modern kernel, what a miracle! Why can't Linux's userspace do something like that?) and install it in there. Or just listen to "JuST doN'T rUN ouTdaTED SoftWAre" advices. Yeah, thanks a lot.