Configure user resource limits

Alex is a RHEL Sysadmin at Ubiquity. He needs to teach a class of interns how to configure user resource limits on a modern RHEL server. He needs to show them a diverse list of samples commands to teach them. Please generate and explain several example commands to teach the class.

Certainly! Here are several example commands that Alex can use to teach the interns how to configure user resource limits on a modern RHEL server:

1. Set the maximum number of open file descriptors (files) for a user:
   • sudo ulimit -n 500

   • This command sets the maximum number of open file descriptors for the current user to 500. It limits the number of files the user can have open simultaneously.

2. Set the maximum amount of CPU time a user can consume:
   • sudo prlimit --cpu=2:4 <username>
   • This command sets the CPU time limit for the specified <username> to a range of 2 to 4 seconds. It restricts the maximum amount of CPU time the user's processes can consume.
3. Limit the maximum amount of memory a user can allocate:
   • sudo ulimit -v 500000
   • This command restricts the maximum amount of virtual memory a user can allocate to 500000 kilobytes. It limits the memory usage of the user's processes.
4. Set the maximum size of core files for a user:
   • sudo ulimit -c unlimited
   • This command sets the maximum size of core files to unlimited for the current user. It allows the user's processes to generate core dump files of any size upon crashing.
5. Restrict the maximum number of processes a user can create:
   • sudo prlimit --nproc=100:200 <username>
   • This command limits the maximum number of processes the specified <username> can create to a range of 100 to 200. It helps control the number of concurrent processes a user can initiate.
6. Set the maximum size of locked memory for a user:
   • sudo ulimit -l 32768
   • This command sets the maximum size of locked memory to 32768 kilobytes for the current user. It limits the amount of memory that can be locked into RAM by the user's processes.

By explaining and demonstrating these example commands, Alex can teach the interns how to configure various user resource limits on a modern RHEL server. This will enable them to effectively manage and control resource allocation for different users and processes.