Flat-style illustration of a server wirelessly sending monitoring data to a laptop displaying a line graph, representing the concept of Zabbix custom data flow without any text.

Send Custom Monitoring Data to Zabbix Using zabbix_sender

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Zabbix is a powerful monitoring tool, and one of its most flexible features is the ability to send custom data using the zabbix_sender command. In this guide, you’ll learn step-by-step how to configure and use this functionality.

Requirements

Before proceeding, make sure you meet the following requirements:

  1. A Zabbix Server is already installed and running.
    Check our guide to deploy Zabbix using Docker.
  2. At least one client (host) is registered in Zabbix.
    Check our guide to autoregister client VM’s on Zabbix Server.
  3. The client has network access to the Zabbix Server.
  4. You have root or sudo privileges on the client machine.

1. Add the Zabbix Repository

First, make sure the Zabbix repository is added to your system. For Rocky Linux 9, run:

rpm -Uvh https://repo.zabbix.com/zabbix/7.0/rocky/9/x86_64/zabbix-release-latest-7.0.el9.noarch.rpm

2. Install the zabbix-sender Tool

Install the package using DNF:

dnf install zabbix-sender

3. Create a New Template and Item in Zabbix

Go to your Zabbix web interface and follow these steps:

  1. Navigate to Configuration > Templates and create a new template.
  2. Assign this template to the desired host (e.g., vm-client-1).
  3. Inside the template, create a new Item with the following key settings:
    • Type: Zabbix Trapper
    • Key: A descriptive name, e.g., custom_item_sender
    • Type of Information: Numeric (unsigned), text, etc., depending on the data you’re sending

This tells Zabbix to passively wait for data instead of actively polling.

4. Verify the Item in Zabbix

Go to Monitoring > Latest data, filter by your host and item name, and confirm the item is listed. Initially, it will have no value.

Custom item showing no values

5. Send Custom Data Using zabbix_sender

On the monitored machine, use the following command to send data to the Zabbix server:

zabbix_sender -z <ZABBIX_SERVER_IP> -s <HOST_NAME> -k <ITEM_KEY> -o <VALUE>

Example

zabbix_sender -z ZABBIX_SERVER_IP -s vm-client-1 -k custom_item_sender -o 0

#OUTPUT:
root@vm-client-1# zabbix_sender -z ZABBIX_SERVER_IP -s vm-client-1 -k custom_item_sender -o 0
Response from "ZABBIX_SERVER_IP:10051": "processed: 1; failed: 0; total: 1; seconds spent: 0.000388"
sent: 1; skipped: 0; total: 1

After a few seconds, the value will appear in the Latest Data section of the Zabbix UI.

This setup allows you to send custom metrics (disk usage, log parsing results, script outputs, etc.) from any client to your Zabbix server. Combined with triggers, it becomes a powerful way to monitor exactly what matters most to your infrastructure.