I follow the red hat documents to create three groups for three users using command:
cgcreate -t uid:gid -a uid:gid -g subsystems:group
Say user A,B,C belong to group 1,2,3 respectively.
But using this method, A can modify the cpu.shares file to set a very large number so he can take more cpu shares from B and C. I don't think this is the right way to create group, any suggestion?
Besides, even the groups are created, if any user run their processes without using cgexec, will the restriction fails? Will the system put these processes to any group (a default one maybe)? If so, what is the behavior of the default group?