Install samba and krb from yum, then run the following…
authconfig --disablecache \
--enablewinbind \
--enablewinbindauth \
--smbsecurity=ads \
--smbworkgroup=howard.local \
--smbrealm=HOWARD.LOCAL \
--enablewinbindusedefaultdomain \
--winbindtemplatehomedir=/home/%U \
--winbindtemplateshell=/bin/bash \
--enablekrb5 \
--krb5realm=HOWARD.LOCAL \
--enablekrb5kdcdns \
--enablekrb5realmdns \
--enablelocauthorize \
--enablemkhomedir \
--enablepamaccess \
--updateall
net ads join -S ad.howard.local -U administrator
net ads dns register -U administrator