新部署天翼云主機，新建普通賬戶zkml，使用root密碼和zkml密碼都可以單獨正常登陸。普通賬戶登錄后su root輸入正確密碼提示如下錯誤：

測試

根據網絡查看su和passwd權限都是正確rws。
最后查詢到有人說需要將普通賬戶添加到wheel組才能使用,在root賬戶下修改

[root@ecs-98b1-0002 ~]# usermod -a -G wheel zkml
[root@ecs-98b1-0002 ~]# id zkml
uid=500(zkml) gid=500(zkml) groups=500(zkml),10(wheel)
gpasswd -d zkml wheel 刪除組中zkml用戶

正常切換

第二種解決方法：
因為安全認證PAM原因導致必須是在wheel組才能是有su root。如果注銷也可以正常切換

#auth required pam_wheel.so use_uid

vi /etc/pam.d/su
#%PAM-1.0
auth            sufficient      pam_rootok.so
# Uncomment the following line to implicitly trust users in the "wheel" group.
#auth           sufficient      pam_wheel.so trust use_uid
# Uncomment the following line to require a user to be in the "wheel" group.
auth            required        pam_wheel.so use_uid  #主要是此處導致，將此處注銷掉也可以
auth            include         system-auth 
account         sufficient      pam_succeed_if.so uid = 0 use_uid quiet
account         include         system-auth
password        include         system-auth
session         include         system-auth
session         optional        pam_xauth.so

安全考慮不建議使用第二章方法