[CentOS] UID/GID CentOS 6 to CentOS 7

Thu Oct 22 13:05:11 UTC 2020
Gianluca Cecchi <gianluca.cecchi at gmail.com>

On Thu, Oct 22, 2020 at 2:12 PM Thomas Plant <thomas at plant.systems> wrote:

> Hi,
> we are upgrading some servers from C6 to C7 with a lot of user accounts
> on them (UID>=500).
> CentOS 7 has MIN_UID/MIN_GID 1000, Centos 6 has 500 in login.defs.
> Can I change in /etc/login.defs MIN_UID/MIN_GID to 500 for C7? So I
> could just grep the users out from passwd/shadow/group files and append
> them to the Centos7 passwd/shadow/group files.
> Can this do any damage to CentOS7 later on? Thinking about updates....
> Thanks,
> Thomas

reading official doc here for upstream:


The default range of IDs for system and normal users has been changed in
Red Hat Enterprise Linux 7 from earlier releases. Previously, UID 1-499 was
used for system users and values above for normal users. The default range
for system users is now 1-999. This change might cause problems when
migrating to Red Hat Enterprise Linux 7 with existing users having UIDs and
GIDs between 500 and 999. The default ranges of UID and GID can be changed
in the /etc/login.defs file.

and also here:

The default ranges of UID and GID can be manually changed in the
/etc/login.defs file.
It seems you can safely change the settings in your CentOS 7 system. I
think no new effective system users/groups already occupying the new range