Usm checker EN

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This module is a replacement for the deprecated usm_ping module

Description

The module is designed to determine the availability of network nodes (including the availability of user devices).

To determine availability, various methods of verification are used, which give more reliable results depending on the specifics of particular networks or devices.

The module is analytical and cannot determine the activity of a node in the network with 100% reliability. For example, if ICMP requests are blocked on the tested node, the only way to determine the availability of such a node may be to check the entry in the ARP table of the router of this node, but even in the ARP table of the router the data may not be reliable, because the entry in it remains for some time, regardless of the actual availability of the node, or it is not found if there has been no exchange of IP-packets with the node for a long time. Therefore, you should choose inspection methods that give a more accurate result for the device being inspected, or configure the device to respond to ICMP ECHO.

For example, it is not always reasonable to perform a ping check to determine the availability of a user's equipment, since most users are not allowed to have ICMP traffic on their equipment; for this purpose, it is better to use a less accurate method - reading the ARP table, which gives some error, but it can be neglected to determine the availability of users.

At the same time, reading the ARP table to determine the availability of equipment is also not reasonable, because after the loss of availability of equipment, its ARP-entry will be in the ARP-table of the router for some time (depending on the settings of the router, it can be quite a long period); here it is better to use only ICMP-ECHO.

The module replaces the obsolete usm_ping module, which checked node availability only by ping.

Requirements

• Python 3.5
• USERSIDE 3.12.41+ (for version 2.0.0-alpha)
• USERSIDE 3.12.69+ (for version 2.0.0-beta)
• USERSIDE 3.13+ (for version 2.0.0)

Installation

Install Python and the pip package manager

sudo apt install -y python3 python3-dev python3-pip

Download the archive, extract the directory with the module files from it (you should do this also when upgrading). You can use virtual python environment with the appropriate fixes to the commands below, or install everything according to these instructions globally. Navigate to this directory and install the dependencies by entering the following command:

sudo pip3 install --upgrade -r requirements.txt

Then, if this is an initial installation, copy the settings.yml-example file named settings.yml

sudo cp settings.yml-example settings.yml

Edit this file (familiarise yourself with the yaml format beforehand, if necessary):

Specify the correct values for the api section - URL of your USERSIDE and API key.

Configure the required detection methods (checks) as described in the next section Availability Check Strategies. There are three checks of different types in the original example configuration file. The last two are commented out. First review the configuration of the availability check strategies and configure the necessary checks (one is sufficient for a test run) before proceeding.