Use Glances for System Monitoring on Linux

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Glances is a Linux system monitoring dashboard that you can run from the command line or in your web browser. It aims to fit as much data as possible onto a single screen and dynamically adapts to the current screen size.

In this guide, learn how to install and get started with the Glances system monitoring tool.

Before You Begin

  1. If you have not already done so, create a Linode account and Compute Instance. See our Getting Started with Linode and Creating a Compute Instance guides.

  2. Follow our Setting Up and Securing a Compute Instance guide to update your system. You may also wish to set the timezone, configure your hostname, create a limited user account, and harden SSH access.

Note
This guide is written for a non-root user. Commands that require elevated privileges are prefixed with sudo. If you’re not familiar with the sudo command, see the Users and Groups guide.

What is the Glances System Monitoring Tool?

Glances gives you an extensive dashboard for monitoring your system, with the goal of giving you everything you need at a single glance.

It follows on the precedent set by system monitoring tools like htop and more recent iterations like gtop and bottom. You can learn more about these last two in our guides How to Install and Use gtop on Linux and How to Install and Use bottom on Linux, respectively.

Glances sets itself apart primarily in two ways.

  • First, it aims to efficiently display as much information as reasonably possible at one time. gtop, in contrast, gives a minimalist display, focusing only on key pieces of information. bottom, while providing more information than gtop, prioritizes customization over efficiency of the display.

  • Second, Glances can be run as a server. You can run Glances as a simple server, which you can access from another machine. Or you can run it as a web server, which you can access from a web browser on the local or a remote machine.

These features make Glances ideal for monitoring your system remotely and having all the system information you need immediately available.

How to Install Glances

  1. Install Python 3 (if it isn’t already installed), along with the Pip package manager, and the Python developer package.

    • On Debian and Ubuntu, use:

        sudo apt install python3 python3-pip python3-dev
      
    • On AlmaLinux and CentOS, use:

        sudo dnf install python3 platform-python-devel
      
    • On Fedora, use:

        sudo dnf install python3 python3-pip python3-devl
      
  2. Install Glances using the Pip package manager:

     pip3 install --user glances
    
  3. You may need to either restart your shell session (logging out and logging back in) or run the command below for the glances command to become available:

     source ~/.bashrc
    
  4. You can then verify your installation with:

     glances --version
    
Glances v3.2.3.1 with PsUtil v5.8.0
[...]

Installing Optional Modules

Glances has numerous modules to enable optional features. You have two options if you want to install these:

  • To install all of the optional modules, use the following command:

      pip3 install --user glances[all]
    
  • To install select modules only, use the same command, but replace all with the name of each module you want, separating modules with commas. So, to install the modules for the folders section, the GPU display, and the web server, you can use:

      pip3 install --user glances[folders,gpu,web]
    

Some of these modules require you to install other dependencies on your system. You can get a full list of these dependencies on the README for Glances.

You can also use the command below to get a full list of Glances modules:

glances --modules-list

The rest of this guide assumes that you’ve installed all of the modules, using the glances[all] command above. However, it doesn’t require you to have installed any of the other dependencies listed in the Glances README.

How to Use Glances System Monitoring

At its simplest, you can immediately start using Glances to monitor your local system. But you can also take advantage of Glances' options, from interactive commands, to client–server arrangements, to fine-grained configurations.

The next few sections walk you through some of these options, aiming to get you started with the most useful of them as a foundation. Afterward, you’re ready to start using Glances and dive deeper into tuning it precisely to fit your needs.

Basic Usage

You can open up the default glances view with the basic command alone. This includes any modules you’ve set up using the Glances configuration file, which you can learn more about in the Example Configurations section below:

glances

If you resize the screen housing the Glances interface, Glances dynamically adapts:

glances display adapted to a smaller window

Once you’re in Glances, there are plenty of interactive commands you can use to control the interface. You can find the full in the Glances official documentation. Below, you can find a selection of some of the most useful interactive commands to get you started:

  • Use the Up and Down arrow keys to move up and down the list of processes.

  • Use the Left and Right arrow keys to select different columns of the processes list. Doing so automatically sorts the list by the newly-selected column.

  • Press Enter to start filtering the processes list. A prompt allows you to enter a regular expression (regex) that the list gets filtered by. You can also prefix the regex with the designation for a specific column to search. The available designations are listed on the filtering prompt.

    Below is an example that filters for any occurrences of pyth within the Command column:

      cmdline:.*pyth.*
    

    Once you have filtered the processes, you can press Enter again to edit your filter or press E (case sensitive) to reset the filter.

  • The 1 key toggles the CPU display between a summary view and a per-CPU view.

  • The 2 key toggles the left side bar, which, by default, includes network, file usage, and sensor information, among others.

  • The 3 key toggles the “quick look” block on the top bar, which provides a graphical summary of CPU and memory usage.

  • The 4 key toggles everything but the “quick look” and load displays on the top bar.

  • The 5 key toggles the top bar, which displays details about CPU, memory, and load.

  • The 6 key toggles the GPU display mode. This only applies for systems with GPUs and with the appropriate module installed. See the Installing Optional Modules section above for more on this.

Glances also has a suite of command-line options, a few of which you can see in the next section ( Setting Up Clients and Servers). The full list is available in the official documentation. The list below aims to give you two of the other most useful kinds of command-line options for getting you started with Glances.

  • You can use the --enable-plugin and --disable-plugin flags to enable and disable particular plugins. For example:

      glances --enable-plugin connections --disable-plugin sensors
    
  • You can export the information from Glances using the --export flag followed by the format for the export, csv or json. You then need to use either the --export-csv-file or --export-json-file flag alongside the --export flag to specify the output filename.

    This example shows you how you can export a JSON file for a default glances execution:

      glances --export json --export-json-file glances-output.json
    

Setting Up Clients and Servers

Glances has the ability to be run as a server, which lets you access the dashboard remotely and/or from a web browser.

Before running Glances as a server, you need to open the appropriate port on the server machine’s firewall to allow remote access. The default port for Glances is 61209, so the options below show how to open that port based on your Linux distribution.

  • On Debian and Ubuntu, make sure you have UFW installed and enabled, which you can learn about in our guide How to Configure a Firewall with UFW. Then, you can use the command below to open the port for Glances:

      sudo ufw allow 61208
      sudo ufw reload
    
  • On AlmaLinux, CentOS, and Fedora, use the command below to open the port with FirewallD. You can read the Introduction to FirewallD on CentOS guide for more on this firewall tool:

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

To start a Glances server for command-line access, follow these steps:

  1. On the machine you want to serve Glances from, issue the following command:

     glances -s
    

    Glances indicates that it’s started up a server, with an output similar to the example below. You can stop the server at any time with Ctrl + C:

    Glances XML-RPC server is running on 0.0.0.0:61209
    Announce the Glances server on the LAN (using 192.0.2.0 IP address)
  2. On the machine you want to access Glances on, make sure you have Glances installed, and then use the command below to connect to your server. Replace 192.0.2.0 with the IP address for the machine you’re serving Glances from:

     glances -c @192.0.2.0
    

A Glances web server allows you to access the monitoring dashboard from either a local or remote web browser. To start a Glances web server follow the steps below:

  1. On the machine you want to serve Glances from, issue the following command:

     glances -w
    

    Glances indicates that it’s started up a web server, with an output similar to the example below. You can stop the server at any time with Ctrl + C:

    Glances Web User Interface started on http://0.0.0.0:61208/
  2. In a web browser, navigate to your server’s IP address and the Glances port number, given in the output when you started up the web server.

    • For local access, you can use an address like:

        localhost:61208
      
    • For remote access, use something like the following, replacing 192.0.2.0 with your server machine’s actual IP address:

        http://192.0.2.0:61208
      

    The output from glances displays in your web browser:

Example Configurations

Every module in Glances can be configured using its configuration file. Your Glances installation doesn’t include the configuration file by default, but you can find a comprehensive example on the Glances GitHub repository. Each section in this example configuration file comes with descriptions to help you figure out what parameters to use and how to use them.

You can find a short configuration example below that focuses on some key kinds of configuration options.

  • First, global configuration options can let you control how Glances behaves overall. In this example, the duration before Glances refreshes its information is extended and Glances is told to check for updates at each startup.

  • Second, several modules require basic configuration before they display in Glances. folders and ports are two such modules. Below, both get configurations identifying what should be monitored, as well as some additional controls for the monitoring.

File: ~/.config/glances/glances.conf
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[global]
refresh=10
check_update=True

[folders]
disable=False
folder_1_path=/home/example-user
folder_1_careful=2500
folder_1_warning=3000
folder_1_critical=3500
folder_1_refresh=60

[ports]
refresh=30
timeout=3
port_default_gateway=True
port_1_host=google.com
port_1_port=80
port_1_description=Google

Conclusion

You are now ready to start using Glances for your system-monitoring needs. If you’re ready to go deeper, take a look at the links below to the official documentation for Glances. Specifically, the Read the Docs for glances is extensive, with many details to get your system monitoring setup where you want it to be.

More Information

You may wish to consult the following resources for additional information on this topic. While these are provided in the hope that they will be useful, please note that we cannot vouch for the accuracy or timeliness of externally hosted materials.

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