Monitor your old Linux devices
Watching Grampa
Create monitoring dashboards with SSH, command-line tools, and Node-RED.
Some excellent technologies and packages are available for monitoring computer hardware. For medium to large systems, the Simple Network Monitoring Protocol (SNMP) approach is usually the preferred solution. However if you have a smaller system with older or low-end servers, some excellent lightweight command-line monitoring utilities can be used instead.
These command-line utilities can be run remotely over Secure Shell (SSH) and the output parsed to return only the key data values, which can then be displayed graphically in a Node-RED web dashboard (Figure 1). In this article, I demonstrate examples that use the iostat
utility [1] to monitor CPU utilization and the lm-sensors package [2] and hddtemp
utility [3] to monitor temperatures on dashboards.
CPU Utilitization
The iostat
utility is part of the sysstat package and is probably already loaded on your older systems. If not, it can be installed by:
sudo apt-get install sysstat
The iostat
utility generates a report for CPU, device, and filesystem utilization. The output from this command can be parsed with some Bash statement to return just the key value of interest.
Listing 1 shows an example of how to grab the fourth line of output with sed (line 7) and parse the %idle value at the end of the line with awk (line 11) to get the sixth string item (line 12).
Listing 1
Parsing iostat Output
01 pete@lubuntu: ~$ iostat -c 02 Linux 4.15.0-72-generic (lubuntu) 2020-05-02 i686 (4 CPU) 03 avg-cpu: %user %nice %system %iowait %steal %idle 04 8.37 0.03 3.33 1.29 86.97 05 06 # Get 4th line of the iostat output 07 pete@lubuntu : ~$ iostat -c | sed -n 4p 08 8.36 0.03 3.33 1.29 0.00 86.99 09 10 # Now get the 6th string 11 pete@lubuntu : ~$ iostat -c | sed -n 4p | awk '{print $6}' 12 87.02
Chip-Based Temperature
To install the hardware sensors in the lm-sensors package, enter:
sudo apt-get install lm-sensors
After the package is installed, the software needs to detect which sensors are available for monitoring:
sudo sensors-detect
This step presents a number of prompts about which sensors need to be scanned. Once the scan step is complete, the sensors command returns results for all the hardware it found.
Specific sensors can be shown with the command:
sensors <chip name>
Listing 2 shows an example of the sensors
command being used to look at the dell_smm-virtual-0 chipset. The CPU temperature value (in line 5) can be parsed with grep
(line 10), which looks for the line that contains "CPU'; then, awk (line 14) outputs the second item of the string (line 15).
Listing 2
Parsing Sensor Data
01 pete@lubuntu: ~$ sensors dell_smm-virtual-0 02 dell_smm-virtual-0 03 Adapter: Virtual device 04 Processor Fan: 2687 RPM 05 CPU: +40.0°C 06 Ambient: +34.0°C 07 SODIMM: +33.0°C 08 09 # Get the CPU temperature 10 pete@lubuntu: ~$ sensors dell_smm-virtual-0 | grep 'CPU' 11 CPU: +40.0°C 12 13 # Return just the temperature 14 pete@lubuntu: ~$ sensors dell_smm-virtual-0 | grep 'CPU' | awk '{print $2}' 15 +40.0°C
Hard Drive Temperature
The hddtemp hard drive temperature monitoring package is installed with:
sudo apt-get install hddtemp
By default, hddtemp requires superuser rights, so to make the results available to non-superusers use:
sudo chmod u+s /usr/sbin/hddtemp
To see the temperature of a hard drive, enter its device name. For example, to see /dev/sda
, use:
$ hddtemp /dev/sda /dev/sda: WDC WD3200BPVT-75JJ5T0: 34°C
Again, you can use the awk
command to parse the output to get just the temperature. For this example, the temperature is the fourth item of the string, so the command displays that value as shown here:
$ hddtemp /dev/sda | awk '{print $4}' 34°C
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Canonical Bumps LTS Support to 12 years
If you're worried that your Ubuntu LTS release won't be supported long enough to last, Canonical has a surprise for you in the form of 12 years of security coverage.
-
Fedora 40 Beta Released Soon
With the official release of Fedora 40 coming in April, it's almost time to download the beta and see what's new.
-
New Pentesting Distribution to Compete with Kali Linux
SnoopGod is now available for your testing needs
-
Juno Computers Launches Another Linux Laptop
If you're looking for a powerhouse laptop that runs Ubuntu, the Juno Computers Neptune 17 v6 should be on your radar.
-
ZorinOS 17.1 Released, Includes Improved Windows App Support
If you need or desire to run Windows applications on Linux, there's one distribution intent on making that easier for you and its new release further improves that feature.
-
Linux Market Share Surpasses 4% for the First Time
Look out Windows and macOS, Linux is on the rise and has even topped ChromeOS to become the fourth most widely used OS around the globe.
-
KDE’s Plasma 6 Officially Available
KDE’s Plasma 6.0 "Megarelease" has happened, and it's brimming with new features, polish, and performance.
-
Latest Version of Tails Unleashed
Tails 6.0 is based on Debian 12 and includes GNOME 43.
-
KDE Announces New Slimbook V with Plenty of Power and KDE’s Plasma 6
If you're a fan of KDE Plasma, you'll be thrilled to hear they've announced a new Slimbook with an AMD CPU and the latest version of KDE Plasma desktop.
-
Monthly Sponsorship Includes Early Access to elementary OS 8
If you want to get a glimpse of what's in the pipeline for elementary OS 8, just set up a monthly sponsorship to help fund its continued existence.