Configure Collectd as a Central Monitoring Server for Clients

Collectd is a popular system statistics collection daemon that gathers and reports on a variety of system performance metrics such as CPU usage, memory usage, disk usage, and network traffic, to name a few. It is widely used to monitor systems and applications in real-time and helps to identify bottlenecks and performance issues.

In this article, we will guide you through the process of configuring Collectd as a central monitoring server for clients, which allows you to collect and analyze data from multiple systems on a single server.

Prerequisites

Before we dive into configuring Collectd, you will need the following −

• A server running Linux, preferably Ubuntu or Debian.

• One or more client machines running Linux, also preferably Ubuntu or Debian.

• Collectd installed on both the server and client machines.

• Basic knowledge of Linux commands and configuration.

Step 1: Install Collectd on the Server

To begin, we need to install Collectd on our server machine. In Ubuntu or Debian, we can install Collectd using the following command −

sudo apt-get install collectd

Once installed, we need to make some changes to the Collectd configuration file.

Step 2: Configure Collectd on the Server

Collectd uses a configuration file called collectd.conf, which is located in the /etc/collectd/ directory. Open this file using a text editor and make the following changes −

• Uncomment the following lines −

LoadPlugin network
<Plugin network>
   Server "localhost" "25826"
</Plugin>

The LoadPlugin line enables the network plugin, which allows Collectd to communicate over the network. The Server line specifies the IP address or hostname and port number of the Collectd server. In this case, we're specifying localhost as the server, which means we're setting up Collectd to receive data from the same machine it's running on.

• Add the following line −

Include "/etc/collectd/conf.d/"

This line tells Collectd to include configuration files located in the /etc/collectd/conf.d/ directory. We'll use this directory later to add configuration files for our client machines.

Save the changes and close the file.

Step 3: Install Collectd on the Client Machines

Now that Collectd is set up on our server, we need to configure it on our client machines. Install Collectd on each client machine using the same command we used on the server −

sudo apt-get install collectd

Once installed, we need to make some changes to the Collectd configuration file.

Step 4: Configure Collectd on the Client Machines

Open the Collectd configuration file (collectd.conf) located in the /etc/collectd/ directory on each client machine and make the following changes −

• Uncomment the following lines −

LoadPlugin cpu
LoadPlugin memory
LoadPlugin network

These lines enable the cpu, memory, and network plugins, which collect statistics for CPU usage, memory usage, and network traffic, respectively.

• Add the following line −

<Plugin network>
   Server "server_ip_address" "25826"
</Plugin>

Replace server_ip_address with the IP address of the Collectd server. This line specifies the Collectd server to send data over the network.

Save the changes and close the file.

Step 5: Restart Collectd on the Server and Clients

After making changes to the configuration files, we need to restart Collectd on the server and client machines using the following command −

sudo systemctl restart collectd

Step 6: Verify Collectd Communication

To verify that Collectd is able to communicate with the clients, we can use the following command −

sudo collectdctl listval <client_hostname>

This will show all the metrics being collected from the specified client. If you are getting output that means Collectd is successfully communicating with the client.

Step 7: Configuring a Web Interface

By default, Collectd doesn't come with a web interface. However, there are various plugins available for Collectd that provide a web interface to visualize the collected data. One of the popular plugins is the "collectd-web" plugin.

To install this plugin on the Collectd server, use the following command −

sudo apt-get install collectd-web

After installing the plugin, you need to configure it to work with Collectd. Open the Collectd configuration file with your favorite text editor −

sudo nano /etc/collectd/collectd.conf

Then add the following lines to the file −

LoadPlugin "network"
LoadPlugin "python"
<Plugin "python">
   ModulePath "/usr/share/collectd/python"
   Import "collectdweb.collectdweb"
   <Module "collectdweb">
      BaseURL "/collectdweb"
   </Module>
</Plugin>

Save and close the file. Then restart Collectd to apply the changes −

sudo systemctl restart collectd

Now, you can access the Collectd web interface by opening a web browser and navigating to http://<server_ip>/collectdweb. You should see a dashboard displaying the metrics collected from the clients.

Step 8: Visualizing Metrics with Grafana

Grafana is a popular open-source platform for visualizing time-series data. It supports a wide range of data sources and provides various visualization options to create custom dashboards.

To use Grafana with Collectd, we need to configure Collectd to write data to InfluxDB, a time-series database. InfluxDB is a popular choice for storing time-series data and it integrates well with Grafana.

To install InfluxDB, use the following command −

sudo apt-get install influxdb

After installing InfluxDB, start the service and enable it to start automatically at boot time −

sudo systemctl start influxdb
sudo systemctl enable influxdb

Next, we need to create a database in InfluxDB to store the collected metrics. To create a database, use the following command −

influx
> create database collectd
> exit

Now, we need to configure Collectd to write data to InfluxDB. Open the Collectd configuration file again −

sudo nano /etc/collectd/collectd.conf

Then add the following lines to the file −

LoadPlugin "network"
LoadPlugin "write_influxdb"
<Plugin "write_influxdb">
   <Node "collectd">
      Host "<server_ip>"
      Port "8086"
      Database "collectd"
      Username "<influxdb_username>"
      Password "<influxdb_password>"
      SSL true
   </Node>
</Plugin>

Replace <server_ip>, <influxdb_username>, and <influxdb_password> with your actual values. Save and close the file. Finally, restart Collectd to apply the changes −

sudo systemctl restart collectd

Now, Collectd will write data to InfluxDB. To visualize the collected data with Grafana, we need to install and configure Grafana.

To install Grafana, use the following commands −

sudo apt-get install -y apt-transport-https gnupg2 curl
curl -s https://packages.grafana.com/gpg.key | sudo apt-key add -
sudo add-apt-repository "deb https://packages.grafana.com/oss/deb stable main"
sudo apt-get update
sudo apt-get install grafana

After installing Grafana, start the service and enable it to start automatically at boot time −

sudo systemctl start grafana-server
sudo systemctl enable grafana-server

Now, open a web browser and navigate to http://<server_ip>:3000. You will see the Grafana login page. Log in using the default credentials (username: admin, password: admin).

After logging in, you will be prompted to change the default password. Follow the on-screen instructions to change the password.

Next, we need to add the InfluxDB data source to Grafana. Click on the "Add data source" button on the home page, select "InfluxDB" as the data source type, and fill in the following fields −

• Name − Enter a name for the data source (e.g., "InfluxDB").

• URL − Enter the URL of your InfluxDB server (e.g., "http://localhost:8086").

• Database − Enter the name of the database you created in InfluxDB (e.g., "collectd").

• User − Enter the username for accessing InfluxDB.

• Password − Enter the password for accessing InfluxDB.

Leave the other fields at their default values and click on the "Save & Test" button. If the connection is successful, you should see a green "Data source is working" message.

Now, we can create a dashboard to visualize the collected metrics. Click on the "New dashboard" button on the home page, and select "Add panel". Choose a visualization type (e.g., "Graph") and select the InfluxDB data source you added earlier. Select the metric you want to visualize from the drop-down menus, and configure the visualization options as desired. Repeat this process to add more panels to the dashboard.

Once you have created the dashboard, you can save it and share it with others by exporting it as a JSON file or by embedding it in a web page.

Conclusion

Collectd is a powerful and versatile tool for monitoring system performance metrics on multiple machines. By configuring Collectd as a central monitoring server and using plugins like Collectd-web and Grafana, you can easily collect, visualize, and analyze data from various sources in real-time.

With the steps outlined in this tutorial, you should now be able to set up Collectd on a server and configure it on multiple client machines, as well as visualize the collected data using Grafana. By monitoring your systems with Collectd, you can identify and troubleshoot bottlenecks and performance issues before they become major problems.