Fix CMOS Battery Issue with NTP: the NetworkManager Edition

While in the previous article, I described a solution to trigger a script when the network goes up. This works on most server Linux setups but it does not work if you are using NetworkManager. NetworkManager has a different way of doing this. If you are not sure whether you are using NetworkManager, consider this: if you are using a wireless network and configuring it using an applet in the task bar or through a GUI program, it's likely that you are using NetworkManager. That and the fact that the script in my previous article didn't work.

NetworkManager applet (Photo credit: Wikipedia)

NetworkManager can still do it. It can run scripts after a network interface is connected or disconnected. It's just not apparently forthright about it. But first a little clarification. In Linux parlance, when a network is connected, it is known as "a network being brought up". This is because the network interface state is changed from DOWN to UP.  And vice versa. When talking about network connections, both set of terms are used interchangeably.
NetworkManager offers this feature through a mechanism called a dispatcher. Basically, the dispatcher looks into the /etc/NetworkManager/dispatcher.d directory and run scripts saved in there. Scripts start with a two digit number that determines the order they are run. The scripts are passed two parameters from the main NetworkManager system. They are the network interface that was connected or disconnected and whether it was connected or disconnected.
In my case, I didn't care which network interface it was but it had to be just connected. So the script looked something like this.

#!/bin/sh
#
# Run ntpdate when network interface goes up using NetworkManager
#
export LC_ALL=C
if [ "$2" = "up" ]; then
        /usr/sbin/ntpdate -u pool.ntp.org
        logger Updated time due to network interface going up
fi

Save the file as 10-ntpdate.sh and change it's attributes to be executable. Drop that into the /etc/NetworkManater/dispatcher.d directory. That's it.

Solve CMOS Battery Issues with NTP

Hewlett-Packard Mini 1000 netbook Photo credit: Wikipedia)

I guess it was time. My HP Mini 1000 netbook was giving me the wrong time and date every time it booted up. It made going to websites with HTTPS impossible because I was apparently accessing them from the past. Resetting the time didn't work because it would forget the current time and reset back to 2002. I would then manually reset the time using ntpdate.
After a few times, I got tired of this and decided that there is a better way. Since the netbook is connected to the Internet most of the time, I knew that a script could be triggered to run every time the network card started up. All I needed to do was to add the ntpdate command and options to it. Problem was I didn't know what script it was. I wasn't also big on making a custom change that would affect future updates.
I knew the scripts that set the network configuration was in /etc/sysconfig/network-scripts. My network interface family was eth so the script that set it up was /etc/sysconfig/network-scripts/ifup-cfg. At the of end of the file was the command

exec /etc/sysconfig/network-scripts/ifup-post ${CONFIG} ${2}

Reading the /etc/sysconfig/network-scripts/ifup-post file, I found the following command at the end.

if [ -x /sbin/ifup-local ]; then
    /sbin/ifup-local ${DEVICE}
fi

However, the file /sbin/ifup-local does not exist. So I created one with the ntpdate -u pool.ntp.org command in it.  So now, every time the network is configured, the time is correct.
I know it doesn't address the problem of the battery being dead or needing replacement but it'll do for now.

This didn't work for you? Maybe you're using NetworkManager. Run NTPDate automatically with NetworkManager too.