- A Cloud Guru
Maintaining Linux Systems
In this lab, we are going to practice scheduling updates, modifying NTP settings, and changing what kernel the server will reboot into. Understanding how to do these tasks will prepare you for various administrative duties in the future. *This course is not approved or sponsored by Red Hat.*
Table of Contents
Schedule a Job Using the `at` Utility
To schedule commands using the
atcommand, you can run
at> yum update -y
Ctrl+Dwill show a message, then send you back to the shell.
You can run
atqto verify that the command is scheduled.
If you get an error similar to:
Can't open /var/run/atd.pid to signal atd. No atd running?
That means that the atd service isn't running. You can resolve that by running
systemctl start atd
Modify the NTP Pools to Keep Clocks Synchronized
NTP configuration is set in
The lines that need to be modified are at the top of the file. Edit them to look like:
server 0.pool.ntp.org iburst
Modify GRUB to Boot a Different Kernel
List the currently installed kernels with
Find the line that looks like
You'll see information about that kernel following the index.
grubby --set-default-index=<index number>
grubby --default-indexto verify it worked.
What's a lab?
Hands-on Labs are real environments created by industry experts to help you learn. These environments help you gain knowledge and experience, practice without compromising your system, test without risk, destroy without fear, and let you learn from your mistakes. Hands-on Labs: practice your skills before delivering in the real world.