Why chroot passwd in CentOS 7.3 is no longer working? 7.0 was OK

Question

I was trying to change password of a CentOS 7.3 virtual machine by the rootjail mechanism.

I used to mount the vm's disk on host and then type in chroot /mountpoint passwd, but this time the vm's password remained unchanged. I can recall that every release before 7.3, this approach is working.

Could anyone tell me what had been changed recently?

Answer 1

I have known the reason. It was because I didn't turn off selinux.