Limiting the number of open files using the ulimit command.

Cedric is a RHEL Sysadmin at Google. He administers a RHEL server, RHEL_Server_1097B with only two users: his account (cedric.bolager@google.com) and his colleague's account, Madra Lopez (madra.lopez@google.com). So that the server is not bogged down, he wants to limit Madra's account to 1,000 open files at any given time. Cedric always uses sudo: he never runs commands as the root user. Please list and explain all of the commands that Cedric will have to run.

Cedric can achieve his goal of limiting Madra's account to 1,000 open files by making changes to the system-wide open file limits. Since Cedric always uses sudo and doesn't run commands as the root user, he should use sudo to execute commands with elevated privileges. Here are the steps Cedric needs to take:

1. Edit the /etc/security/limits.conf file:

   Cedric should edit the /etc/security/limits.conf file to set the open file limits for Madra's account.

   sudo vi /etc/security/limits.conf

   Then, add the following lines to the file:

   madra.lopez soft nofile 1000 madra.lopez hard nofile 1000

   These lines set both the soft and hard limits for the maximum number of open files to 1000 for Madra's account. The soft limit is the initial limit, and the hard limit is the maximum limit that cannot be exceeded.

2. Apply the changes:

   After editing the limits.conf file, Cedric needs to make sure the changes take effect. This usually requires logging out and logging back in or rebooting the system. However, if Cedric wants to apply the changes immediately without rebooting, he can use the ulimit command to set the limits for Madra's current shell session:

   sudo -u madra.lopez ulimit -n 1000

   This command sets the maximum number of open files for Madra's current shell session to 1000.

By making these changes, Cedric effectively limits Madra's account to a maximum of 1,000 open files at any given time. It's important to note that system-wide changes like these can impact multiple sessions and services, so Cedric should carefully consider the implications of these limits on the overall system behavior and Madra's work requirements.