The installation of Red Hat Enterprise Linux 7.2 failed with a python traceback including "exited with status 1" of anaconda-yum

Issue

• The installation of Red Hat Enterprise Linux 7.2 failed with this python traceback.

xx:xx:xx,104 CRIT anaconda: Traceback (most recent call last):
  File "/usr/lib64/python2.7/site-packages/pyanaconda/threads.py", line 227, in run
    threading.Thread.run(self, *args, **kwargs)
  File "/usr/lib64/python2.7/threading.py", line 764, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/install.py", line 225, in doInstall
    payload.install()
  File "/usr/lib64/python2.7/site-packages/pyanaconda/packaging/yumpayload.py", line 1475, in install
    for line in execReadlines("/usr/libexec/anaconda/anaconda-yum", args):
  File "/usr/lib64/python2.7/site-packages/pyanaconda/iutil.py", line 401, in next
    (self._argv, self._proc.returncode))
OSError: process '['/usr/libexec/anaconda/anaconda-yum', '--config', '/tmp/anaconda-yum.conf', '--tsfile', '/mnt/sysimage/anaconda-yum.yumtx', '--rpmlog', '/tmp/rpm-script.log', '--installroot', '/mnt/sysimage', '--release', '7.2', '--arch', 'x86_64', '--macro', '__dbi_htconfig', 'hash nofsync %{__dbi_other} %{__dbi_perms}', '--macro', '__file_context_path', '/etc/selinux/targeted/contexts/files/file_contexts']' exited with status 1

• What is the root cause of this?