How to Install Glances System Monitor on AlmaLinux 8

Glances System Monitor is free, an open-source command-line tool for process monitoring, system resources such as CPU, Disk I/O, File System, Load Average, Memory, Network Interfaces and processes. Glances are built with Python language. Glances support cross-platform monitoring, which can be used with a web-based interface.

One of the excellent features Glances supports is setting thresholds in the program. You can set careful, warning, and critical in the configuration file, which will then relay information in colors that can show alerts to systems resources bottlenecks, system resources issues, and much more. Glances, by default, comes with a pre-set list of colors, but you can modify and add additional configs.

The following tutorial will demonstrate how to install Glances System Monitor on AlmaLinux 8 workstation or server using the command line console, create a systemd service file, create a web service and secure with firewalls, and lastly, some basic commands and maintenance tips.

Update AlmaLinux

First, run a quick update to ensure all your packages are up-to-date to avoid conflicts during the tutorial and installation.

sudo dnf upgrade --refresh

Install Glances System Monitor

By default, Glances is not available on Appstream compared to some other distributions, and you will need to import the EPEL repository using the following command.

sudo dnf install epel-release epel-next-release -y

Before you continue, install the dependencies required to install and use Glances.

sudo dnf install python3 python3-jinja2 python3-psutil python3-setuptools hddtemp python3-pip lm_sensors -y

Next, install Glances using the DNF package manager by executing the following installation command.

sudo dnf install glances -y

Once installed, verify the version, which will check to see if it was installed successfully.

/usr/bin/glances --version

Example output:

Now you would have noticed the path /usr/bin/glances/ being used in the version output. Next, create a systemd service before installing the PIP bottle module.

sudo pip3 install bottle

Now, create the following service file using nano or the text editor of your choice.

sudo nano /etc/systemd/system/glances.service

Next, copy and paste the following.

[Unit]
Description=Glances
After=network.target

[Service]
ExecStart=/usr/bin/glances -w
Restart=on-abort
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target

For users that used the nano editor, use CTRL+O it to save and CTRL+X to exit.

Now, enable the Glances system immediately and on system start.

sudo systemctl enable glances --now

Verify the status of the software by using the following systemctl status command.

systemctl status glances

Example output:

How To Use Glances Monitoring System

Once you have installed the program, familiar wise yourself with some of the basic commands that the tutorial will now cover.

To open Glances, use the following command.

glances

Example terminal look:

To exit the Glances, use the following command.

Ctrl+C

Next, you can alternatively open Glances using a timer to help systems in intensive tasks. By default, the timer is 1, but you can change this as an example:

glances -t 3

This now changes the default time delay from 1 second to 3 seconds. However, you can set this much higher if required.

To bring up the help command, enter the following.

glances -h

Example output:

usage: glances [-h] [-V] [-d] [-C CONF_FILE] [--modules-list]
               [--disable-plugin DISABLE_PLUGIN]
               [--enable-plugin ENABLE_PLUGIN] [--disable-process]
               [--disable-webui] [--light] [-0] [-1] [-2] [-3] [-4] [-5] [-6]
               [--disable-history] [--disable-bold] [--disable-bg]
               [--enable-irq] [--enable-process-extended] [--export EXPORT]
               [--export-csv-file EXPORT_CSV_FILE] [--export-csv-overwrite]
               [--export-json-file EXPORT_JSON_FILE]
               [--export-graph-path EXPORT_GRAPH_PATH] [-c CLIENT] [-s]
               [--browser] [--disable-autodiscover] [-p PORT]
               [-B BIND_ADDRESS] [--username] [--password] [-u USERNAME_USED]
               [--snmp-community SNMP_COMMUNITY] [--snmp-port SNMP_PORT]
               [--snmp-version SNMP_VERSION] [--snmp-user SNMP_USER]
               [--snmp-auth SNMP_AUTH] [--snmp-force] [-t TIME] [-w]
               [--cached-time CACHED_TIME] [--open-web-browser] [-q]
               [-f PROCESS_FILTER] [--process-short-name] [--stdout STDOUT]
               [--stdout-csv STDOUT_CSV] [--hide-kernel-threads] [-b]
               [--diskio-show-ramfs] [--diskio-iops] [--fahrenheit]
               [--fs-free-space] [--sparkline] [--theme-white]
               [--disable-check-update]

optional arguments:
  -h, --help            show this help message and exit
  -V, --version         show program's version number and exit
  -d, --debug           enable debug mode
  -C CONF_FILE, --config CONF_FILE
                        path to the configuration file
  --modules-list, --module-list
                        display modules (plugins & exports) list and exit
  --disable-plugin DISABLE_PLUGIN, --disable-plugins DISABLE_PLUGIN
                        disable plugin (comma separed list)
  --enable-plugin ENABLE_PLUGIN, --enable-plugins ENABLE_PLUGIN
                        enable plugin (comma separed list)
  --disable-process     disable process module
  --disable-webui       disable the Web Interface
  --light, --enable-light
                        light mode for Curses UI (disable all but top menu)
  -0, --disable-irix    task's cpu usage will be divided by the total number
                        of CPUs
  -1, --percpu          start Glances in per CPU mode
  -2, --disable-left-sidebar
                        disable network, disk I/O, FS and sensors modules
  -3, --disable-quicklook
                        disable quick look module
  -4, --full-quicklook  disable all but quick look and load
  -5, --disable-top     disable top menu (QL, CPU, MEM, SWAP and LOAD)
  -6, --meangpu         start Glances in mean GPU mode
  --disable-history     disable stats history
  --disable-bold        disable bold mode in the terminal
  --disable-bg          disable background colors in the terminal
  --enable-irq          enable IRQ module
  --enable-process-extended
                        enable extended stats on top process
  --export EXPORT       enable export module (comma separed list)
  --export-csv-file EXPORT_CSV_FILE
                        file path for CSV exporter
  --export-csv-overwrite
                        overwrite existing CSV file
  --export-json-file EXPORT_JSON_FILE
                        file path for JSON exporter
  --export-graph-path EXPORT_GRAPH_PATH
                        Folder for Graph exporter
  -c CLIENT, --client CLIENT
                        connect to a Glances server by IPv4/IPv6 address or
                        hostname
  -s, --server          run Glances in server mode
  --browser             start the client browser (list of servers)
  --disable-autodiscover
                        disable autodiscover feature
  -p PORT, --port PORT  define the client/server TCP port [default: 61209]
  -B BIND_ADDRESS, --bind BIND_ADDRESS
                        bind server to the given IPv4/IPv6 address or hostname
  --username            define a client/server username
  --password            define a client/server password
  -u USERNAME_USED      use the given client/server username
  --snmp-community SNMP_COMMUNITY
                        SNMP community
  --snmp-port SNMP_PORT
                        SNMP port
  --snmp-version SNMP_VERSION
                        SNMP version (1, 2c or 3)
  --snmp-user SNMP_USER
                        SNMP username (only for SNMPv3)
  --snmp-auth SNMP_AUTH
                        SNMP authentication key (only for SNMPv3)
  --snmp-force          force SNMP mode
  -t TIME, --time TIME  set refresh time in seconds [default: 3 sec]
  -w, --webserver       run Glances in web server mode (bottle needed)
  --cached-time CACHED_TIME
                        set the server cache time [default: 1 sec]
  --open-web-browser    try to open the Web UI in the default Web browser
  -q, --quiet           do not display the curses interface
  -f PROCESS_FILTER, --process-filter PROCESS_FILTER
                        set the process filter pattern (regular expression)
  --process-short-name  force short name for processes name
  --stdout STDOUT       display stats to stdout, one stat per line (comma
                        separated list of plugins/plugins.attribute)
  --stdout-csv STDOUT_CSV
                        display stats to stdout, csv format (comma separated
                        list of plugins/plugins.attribute)
  --hide-kernel-threads
                        hide kernel threads in process list (not available on
                        Windows)
  -b, --byte            display network rate in byte per second
  --diskio-show-ramfs   show RAM Fs in the DiskIO plugin
  --diskio-iops         show IO per second in the DiskIO plugin
  --fahrenheit          display temperature in Fahrenheit (default is Celsius)
  --fs-free-space       display FS free space instead of used
  --sparkline           display sparklines instead of bar in the curses
                        interface
  --theme-white         optimize display colors for white background
  --disable-check-update
                        disable online Glances version ckeck

Examples of use:
  Monitor local machine (standalone mode):
    $ glances

  Display all Glances modules (plugins and exporters) and exit:
    $ glances --module-list

  Monitor local machine with the Web interface and start RESTful server:
    $ glances -w
    Glances web server started on http://0.0.0.0:61208/

  Only start RESTful API (without the WebUI):
    $ glances -w --disable-webui
    Glances API available on http://0.0.0.0:61208/api/

  Monitor local machine and export stats to a CSV file (standalone mode):
    $ glances --export csv --export-csv-file /tmp/glances.csv

  Monitor local machine and export stats to a InfluxDB server with 5s refresh time (standalone mode):
    $ glances -t 5 --export influxdb

  Start a Glances XML/RCP server (server mode):
    $ glances -s

  Connect Glances to a Glances XML/RCP server (client mode):
    $ glances -c <ip_server>

  Connect Glances to a Glances server and export stats to a StatsD server (client mode):
    $ glances -c <ip_server> --export statsd

  Start the client browser (browser mode):
    $ glances --browser

  Display stats to stdout (one stat per line):
    $ glances --stdout now,cpu.user,mem.used,load

  Display CSV stats to stdout (all stats in one line):
    $ glances --stdout-csv now,cpu.user,mem.used,load

  Disable some plugins (comma separated list):
    $ glances --disable-plugin network,ports

  Enable some plugins (comma separated list):
    $ glances --enable-plugin sensors

Alerts in Glances

As mentioned at the start of the tutorial, Glances has the color for alerts. The following describes what they are.

1. GREEN: OK (good)
2. BLUE: CAREFUL (attention)
3. VIOLET: WARNING (alert)
4. RED: CRITICAL (critical)

The thresholds that default settings are as follows.

• careful=50
• warning=70
• critical=90

The default configuration can be changed. To do this, open up the file located at /etc/glances/glances.conf. But firstly, let’s make a backup of the original configuration file for safekeeping which you can revert to if you make a mistake and need a fresh copy.

sudo cp /etc/glances/glances.conf /etc/glances/glances-bkup.conf

Next, open up the main configuration file using the nano text editor.

sudo nano /etc/glances/glances.conf

Copy and paste the following under Global.

[cpu]
disable=False
refresh=3
user_careful=50
user_warning=70
user_critical=90
iowait_careful=50
iowait_warning=70
iowait_critical=90
system_careful=50
system_warning=70
system_critical=90
steal_careful=50
steal_warning=70
steal_critical=90

For example, you would like to change the user CPU usage warning options.

Change from:

user_careful=50
user_warning=70
user_critical=90

Change to (Increased example):

user_careful=70
user_warning=80
user_critical=90

Additionally, you can even edit the [global] settings as follows below, pretty straightforward with history_size, refresh rate.

[global]
# Refresh rate (default is a minimum of 2 seconds)
# Can be overwrite by the -t <sec> option
# It is also possible to overwrite it in each plugin sections
refresh=2
# Does Glances should check if a newer version is available on PyPI ?
check_update=false
# History size (maximum number of values)
# Default is 28800: 1 day with 1 point every 3 seconds
history_size=28800

Example only:

As mentioned above, the tutorial has increased the warning signs. However, you can set your own and increase or even lower what you think is appropriate for your environment and use case. Additionally, more settings can be imported to the glances.conf file as well from the wiki; the list is extensive.

Using the nano text editor, use CTRL+O and CTRL+X to save and exit the file.

Ideally, you should restart the service also using the following command.

sudo systemctl restart glances

Command Options

The following list commands you can use in Glances to configure, find and show what you are looking for.

Command	Description
a	Sort processes automatically
c	Sort processes by CPU%
m	Sort processes by MEM%
p	Sort processes by name
i	Sort processes by I/O rate
d	Show/hide disk I/O stats
f	Show/hide file system statshddtemp
n	Show/hide network stats
s	Show/hide sensors stats
y	Show/hide hddtemp stats
I	Show/hide logs
b	Bytes or bits for network I/O
w	Delete warning logs
x	Delete warning and critical logs
1	Global CPU or per-CPU stats
h	Show/hide this help screen
t	View network I/O as combination
u	View cumulative network I/O
q	Quit (Esc and Ctrl-C also work)

How to Run In Web Browser

For users that require remote monitoring, Glances can do this as all required dependencies are installed by default.

To initiate the browser function in the program, do the following.

glances -w

Note that you will most likely see in the terminal display “Glances Web User Interface started on http://0.0.0.0:61208” when entering this command. This may look a little confusing, using the server’s IP address.

You can set a password for the web-based monitor by typing the following command.

glances -w --password

To open the web browser for the program, enter your IP server address with the default port 61208 as an example.

http://203.15.33.190:61208

Example:

For your primary client, you can keep glances running in the background with the following command.

glances -w &

The above creates a background running process. Now you must disown the current state.

disown

If you need to kill the processors in background mode, type the following to kill all active glances sessions.

killall glances

How to Run Client-Server Mode

Another great feature of the Glances program is that it provides client-server architecture. This means you can run glances on multiple remote servers and connect them to your primary client, and all servers must have Glances installed.

Log in to the remote server start the glance program in server-side mode.

glances -s

After you have finished starting server-side monitoring on all the required servers you need, go to your client system and connect to the system’s IP address running the server-client mode with the following command.

glances -c server-IP-address:61208

Configure Firewalld

By default, no rules are set up for Glances with the system firewall. For users that will have Glances publically accessible, this should be set up to avoid disaster and hacking of your server. Below are some basic firewalld options to create allow rules essential to stop attacks.

First, add a new dedicated zone for Glances firewalld policy:

sudo firewall-cmd --permanent --new-zone=glances

Next, specify the allowed IP addresses permitted to access the Glances.

sudo firewall-cmd --permanent --zone=glances --add-source=1.2.3.4

Replace 1.2.3.4 with the IP address that will be added to the allow list.

Optionally, you can list a subnet.

sudo firewall-cmd --permanent --zone=glances --add-source=1.2.3.4/24

Now open the port of the Glances. By default, this is TCP port 61208.

sudo firewall-cmd --permanent --zone=glances --add-port=61208/tcp

Note you can change the default port in your configuration file if you change the firewall port open rule above to the new value.

After running those commands, reload the firewall to implement the new rules:

sudo firewall-cmd --reload

Example output if successful:

success

Comments and Conclusion

In the tutorial, you have learned how to install the Glances System Monitor on AlmaLinux 8, a step above the default “top” package for monitoring system resources and processors that ship with default Linux installations. This package is ideal, especially if you want a better system overview. It covers much more information and presents it in color codes to signal what the data in front of you means and how it affects your server.

The extra benefit of remote monitoring makes this one of the more popular options for simple server monitoring. It continues to get better with an active development continuing to this day.