This Bug Report affects these Traffic Control components:

• Traffic Ops - Postinstall

Current behavior:

Python Postinstall fails on CentOS 7 if Python 3 is installed (but succeeds if Python 3 is not installed, because it will use Python 2).

Originally reported by @rsidhaarth in the first draft of #6236.

Expected behavior:

the Python Postinstall script should succeed on CentOS 7, with or without Python 3.

Steps to reproduce:

<<'DOCKER_COMMANDS' docker run --rm -iv$(pwd):/opt -w/opt centos:7 bash
yum -y install python3 &&
<<'PYTHON_COMMANDS' PYTHONPATH=traffic_ops/install/bin python3
import _postinstall
print(_postinstall.hash_pass('mysecretpassword'))
PYTHON_COMMANDS
DOCKER_COMMANDS

Output:

[...]
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "/opt/traffic_ops/install/bin/_postinstall.py", line 433, in hash_pass
    hashed = hashlib.scrypt(passwd.encode(), salt=salt, n=n, r=r_val, p=p_val, dklen=dklen)
AttributeError: module 'hashlib' has no attribute 'scrypt'