Chapter 6 - changes persisting after reboot

thebiz

Hi,

I got to the Chapter 6 Learning Objectives Review where it says I should understand how to make startup options and runtime options persist across system reboots. There are some external and man page references given about startup options and nothing explicit given about runtime options persisting after system reboot. There is not sufficient information in the course text and exercises to understand how to make configuration changes persist after reboot.

I found the following exercise useful for understanding runtime options persisting after reboot:

737 ping $HOSTNAME

738 #

739 # Edit /etc/sysctl.conf

740 # Insert "net.ipv4.icmp_echo_ignore_all=1" on the first line

741 sudo vim /etc/sysctl.conf

742 ping $HOSTNAME

743 sudo sysctl -p

744 ping $HOSTNAME

746 sudo shutdown now -r

747 ping $HOSTNAME

748 #

749 # Delete line added to /etc/sysctl.conf

750 sudo vim /etc/sysctl.conf

751 sysctl -p

752 ping $HOSTNAME

753 # Add line to /etc/sysctl.conf

754 # net.ipv4.icmp_echo_ignore_all=0

755 sudo vim /etc/sysctl.conf

757 sudo sysctl -p

758 ping $HOSTNAME

759 #

760 # Remove line added to /etc/sysctl.conf to restore

761 # pre-exercise state

762 sudo vim /etc/sysctl.conf

I have yet to work up courage to try out bootup options...

coop

Section 6.5 (sysctl) says:

"If settings are placed in /etc/sysctl.conf (see man sysctl.conf for details) settings can be fixed at boot time."

It also mentions a little later: "Note on some recent distributions based on systemd (such as RHEL 7) the actual settings file is now /usr/lib/sysctl.d/00-system.conf, but the original file is still supported as is self-documented in that file."

You figured this out for yourself I gather. Please note we try not to just regurgitate man pages and the man page for sysctl.conf is rather detailed, and in fact the file itself contains complete self-documentation.