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: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/ch-managing_users_and_groups " Important 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: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/migration_planning_guide/chap-red_hat_enterprise_linux-migration_planning_guide-major_changes_and_migration_considerations#sect-Red_Hat_Enterprise_Linux-Migration_Planning_Guide-System_Management-Changes-to-system-accounts " 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 slots... HIH, Gianluca