Telegraf

Introduction

The Telegraf agent collects metrics and computes statuses on the servers it monitors, and sends them to Centreon. Centreon's OpenTelemetry processor allows it to understand data sent in OpenTelemetry format.

Developed by InfluxDB, the Telegraf agent can be installed on Windows or Linux servers. Centreon Engine is able to send the configuration of monitored resources to the agent (existing hosts, thresholds...), so that the agent can execute checks and compute the statuses of these resources.

As they are Nagios-based, both Centreon and custom plugins are compatible with the agent. This is because Centreon's Telegraf integration is based on the native Nagios input data format.

Limitations

Due to Telegraf or Centreon constraints, the following limitations need to be considered.

• Due to Telegraf limitations, the configuration of resources known to the agent is only updated when you start or reload the agent (typically, you would do that after deploying the configuration). Technically, the agent requests an up-to-date configuration from Centreon.
• Only known metrics (i.e., the metrics for the hosts and services created in Centreon) are sent to Centreon. Metrics for unknown hosts or services are discarded.
• Only metrics and statuses are returned (no outputs).
• Network connections are one-way only: data goes from the agent to the poller. This means that a host in a DMZ will need a poller in this DMZ.
• When an enhancement or fix is released, the Centreon plugin must be re-deployed on your monitored host (there is no auto-update).

Step 1: Configure Centreon

Install the Monitoring Connector

Linux

1. On your central server, go to Configuration > Monitoring Connector Manager.
2. Install the Linux Telegraf Agent monitoring connector.

Windows

1. On your central server, go to Configuration > Monitoring Connector Manager.
2. Install the Windows Telegraf Agent monitoring connector.

Create the Telegraf connector

Install the Open Telemetry processor for Telegraf on your central server:

1. Go to Configuration > Commands > Connectors.
2. Create a new connector with the following values:

Parameter	Value
Connector Name	Telegraf
Connector Description	Telegraf
Command Line	opentelemetry --processor=nagios_telegraf --extractor=attributes --host_path=resource_metrics.scope_metrics.data.data_points.attributes.host --service_path=resource_metrics.scope_metrics.data.data_points.attributes.service
Used by command	Type Telegraf-Agent and click Select all
Connector Status	Enabled

Configure Engine

Configure how the poller and the agent will communicate:

• Some agents can connect to the poller, while the poller can connect to some other agents.
• You can select several pollers at once in a single configuration form so that you don't have to do the same configuration several times.

1. Go to Configuration > Pollers > Agent configurations and click Add poller/agent configuration.
2. In the window that opens, select the type of agent you want to configure. Additional fields appear.
3. In the Parameters section, select the poller(s) that will receive data from the agent.
4. In the OTLP receiver section, enter the file names for the certificates for the part of the poller that will receive data from the agent, i.e., the poller's engine. Communication between the agent and the poller is always in HTTPS. You need to store the certificates in the /etc/pki/ directory of the poller.

5. The Configuration provider is the server inside the poller's engine that will send the agent its configuration. Enter the port and the file names for the certificates. The certificates must be stored in the /etc/pki/ directory. You can use the same certificates as for the OTLP receiver.

If you configure several pollers at once, make sure all certificate files have the same name.

6. Export the configuration

7. Restart the monitoring engine

   systemctl restart centengine

The Telegraf agent is now able to communicate with Centreon. You can set up the monitoring of your hosts.

Step 2: Prepare the host

Download and install the agent

Linux

Alma / RHEL / Oracle Linux 8

dnf -y install epel-release
dnf -y config-manager --set-enabled 'powertools'

This part is an excerpt from Telegraf's official documentation.

cat > /etc/yum.repos.d/influxdb.repo <<'EOF'
[influxdb]
name = InfluxData Repository - Stable
baseurl = https://repos.influxdata.com/stable/$basearch/main
enabled = 1
gpgcheck = 1
gpgkey = https://repos.influxdata.com/influxdata-archive_compat.key
EOF

dnf install -y telegraf

Then:

1. Stop the Telegraf service

systemctl stop telegraf

2. Edit the telegraf.service file.

vi /etc/systemd/system/telegraf.service

3. Replace:

/usr/bin/telegraf -config /etc/telegraf/telegraf.conf -config-directory /etc/telegraf/telegraf.d $TELEGRAF_OPTS

By (replace the placeholders by your values):

/usr/bin/telegraf -config http(s)://<ip poller>:<port poller>/engine?host=<host to monitor>

4. Start the Telegraf service:

systemctl start telegraf

Alma / RHEL / Oracle Linux 9

dnf -y install epel-release
dnf -y config-manager --set-enabled 'crb'

This part is an excerpt from Telegraf's official documentation.

cat > /etc/yum.repos.d/influxdb.repo <<'EOF'
[influxdb]
name = InfluxData Repository - Stable
baseurl = https://repos.influxdata.com/stable/$basearch/main
enabled = 1
gpgcheck = 1
gpgkey = https://repos.influxdata.com/influxdata-archive_compat.key
EOF

dnf install -y telegraf

Then:

1. Stop the Telegraf service

systemctl stop telegraf

2. Edit the telegraf.service file.

vi /etc/systemd/system/telegraf.service

3. Replace:

/usr/bin/telegraf -config /etc/telegraf/telegraf.conf -config-directory /etc/telegraf/telegraf.d $TELEGRAF_OPTS

By (replace the placeholders by your values):

/usr/bin/telegraf -config http(s)://<ip poller>:<port poller>/engine?host=<host to monitor>

4. Start the Telegraf service:

systemctl start telegraf

Debian 11 & 12

This part is an excerpt from Telegraf's official documentation.

wget -q https://repos.influxdata.com/influxdata-archive_compat.key -O influxdata-archive_compat.key
echo '393e8779c89ac8d958f81f942f9ad7fb82a25e133faddaf92e15b16e6ac9ce4c influxdata-archive_compat.key' | sha256sum -c && cat influxdata-archive_compat.key | gpg --dearmor | tee /etc/apt/trusted.gpg.d/influxdata-archive_compat.gpg > /dev/null
echo 'deb [signed-by=/etc/apt/trusted.gpg.d/influxdata-archive_compat.gpg] https://repos.influxdata.com/debian stable main' | sudo tee /etc/apt/sources.list.d/influxdata.list
apt-get update

apt-get -y install telegraf

You must then configure the Telegraf OpenTelemetry output. You must uncomment this paragraph or recreate a configuration file with just the following lines:

# [[outputs.opentelemetry]]
#   ## Override the default (localhost:4317) OpenTelemetry gRPC service
#   ## address:port
#   # service_address = "localhost:4317"
#
#   ## Override the default (5s) request timeout
#   # timeout = "5s"
#
#   ## Optional TLS Config.
#   ##
#   ## Root certificates for verifying server certificates encoded in PEM format.
#   # tls_ca = "/etc/telegraf/ca.pem"
#   ## The public and private keypairs for the client encoded in PEM format.
#   ## May contain intermediate certificates.
#   # tls_cert = "/etc/telegraf/cert.pem"
#   # tls_key = "/etc/telegraf/key.pem"
#   ## Use TLS, but skip TLS chain and host verification.
#   # insecure_skip_verify = false
#   ## Send the specified TLS server name via SNI.
#   # tls_server_name = "foo.example.com"

If the communication between Telegraf and the poller is not encrypted, you just have to enter the IP address and port of the poller in the service_address option (port entered in the otel_server field in the poller’s configuration). If not, you will also need to provide a value for at least tls_ca.

Now you need to add the Telegraf configuration server provided by the poller. You must create the */etc/default/telegraf file and add the following line:

TELEGRAF_OPTS=-config https://<ip poller>:<http_server port>/engine? host=<host_to_monitor>

The arguments of this command will allow Telegraf to know where to get the configuration of the resources it must monitor (that is to say on the poller or on the central server following the IP address defined in the command). The parameter <host_to_monitor> is the name of the host as entered in the Name field of its configuration.

You now have to restart Telegraf:

systemctl restart telegraf

Windows

1. Download the agent on all the servers you want to monitor.

2. You must then configure the Telegraf OpenTelemetry output. You must uncomment this paragraph or recreate a configuration file with just the following lines:

# [[outputs.opentelemetry]]
#   ## Override the default (localhost:4317) OpenTelemetry gRPC service
#   ## address:port
#   # service_address = "localhost:4317"
#
#   ## Override the default (5s) request timeout
#   # timeout = "5s"
#
#   ## Optional TLS Config.
#   ##
#   ## Root certificates for verifying server certificates encoded in PEM format.
#   # tls_ca = "/etc/telegraf/ca.pem"
#   ## The public and private keypairs for the client encoded in PEM format.
#   ## May contain intermediate certificates.
#   # tls_cert = "/etc/telegraf/cert.pem"
#   # tls_key = "/etc/telegraf/key.pem"
#   ## Use TLS, but skip TLS chain and host verification.
#   # insecure_skip_verify = false
#   ## Send the specified TLS server name via SNI.
#   # tls_server_name = "foo.example.com"

3. Install the agent on the servers using the following command (replace the placeholders by your values):

.\telegraf.exe --service install --config <previous conf file path> --config "http(s)://<ip_poller>:<port poller>/engine?host=<host_to_monitor>"

The arguments in this command will allow Telegraf to know where to fetch the configuration of the resources that it must monitor (i.e on the poller or the central, according to the IP address you have entered in the command). The <host_to_monitor> parameter is the name of the host as you entered it in the Name field in its configuration.

Deploy the Centreon plugin

The Centreon plugin will execute the checks on the host.

Linux

Enable our plugins repository and install the plugin

This repository will provide you our packaged plugins as well as the dependencies that are not available in the standard distribution repositories.

Alma / RHEL / Oracle Linux 8

cat >/etc/yum.repos.d/centreon-plugins.repo <<'EOF'
[centreon-plugins-stable]
name=Centreon plugins repository.
baseurl=https://packages.centreon.com/rpm-plugins/el8/stable/$basearch/
enabled=1
gpgcheck=1
gpgkey=https://yum-gpg.centreon.com/RPM-GPG-KEY-CES
module_hotfixes=1

[centreon-plugins-stable-noarch]
name=Centreon plugins repository.
baseurl=https://packages.centreon.com/rpm-plugins/el8/stable/noarch/
enabled=1
gpgcheck=1
gpgkey=https://yum-gpg.centreon.com/RPM-GPG-KEY-CES
module_hotfixes=1

[centreon-plugins-testing]
name=Centreon plugins repository. (UNSUPPORTED)
baseurl=https://packages.centreon.com/rpm-plugins/el8/testing/$basearch/
enabled=0
gpgcheck=1
gpgkey=https://yum-gpg.centreon.com/RPM-GPG-KEY-CES
module_hotfixes=1

[centreon-plugins-testing-noarch]
name=Centreon plugins repository. (UNSUPPORTED)
baseurl=https://packages.centreon.com/rpm-plugins/el8/testing/noarch/
enabled=0
gpgcheck=1
gpgkey=https://yum-gpg.centreon.com/RPM-GPG-KEY-CES
module_hotfixes=1

[centreon-plugins-unstable]
name=Centreon plugins repository. (UNSUPPORTED)
baseurl=https://packages.centreon.com/rpm-plugins/el8/unstable/$basearch/
enabled=0
gpgcheck=1
gpgkey=https://yum-gpg.centreon.com/RPM-GPG-KEY-CES
module_hotfixes=1

[centreon-plugins-unstable-noarch]
name=Centreon plugins repository. (UNSUPPORTED)
baseurl=https://packages.centreon.com/rpm-plugins/el8/unstable/noarch/
enabled=0
gpgcheck=1
gpgkey=https://yum-gpg.centreon.com/RPM-GPG-KEY-CES
module_hotfixes=1
EOF

Install the plugin:

dnf install -y centreon-plugin-Operatingsystems-Linux-Local.noarch

Alma / RHEL / Oracle Linux 9

cat >/etc/yum.repos.d/centreon-plugins.repo <<'EOF'
[centreon-plugins-stable]
name=Centreon plugins repository.
baseurl=https://packages.centreon.com/rpm-plugins/el9/stable/$basearch/
enabled=1
gpgcheck=1
gpgkey=https://yum-gpg.centreon.com/RPM-GPG-KEY-CES
module_hotfixes=1

[centreon-plugins-stable-noarch]
name=Centreon plugins repository.
baseurl=https://packages.centreon.com/rpm-plugins/el9/stable/noarch/
enabled=1
gpgcheck=1
gpgkey=https://yum-gpg.centreon.com/RPM-GPG-KEY-CES
module_hotfixes=1

[centreon-plugins-testing]
name=Centreon plugins repository. (UNSUPPORTED)
baseurl=https://packages.centreon.com/rpm-plugins/el9/testing/$basearch/
enabled=0
gpgcheck=1
gpgkey=https://yum-gpg.centreon.com/RPM-GPG-KEY-CES
module_hotfixes=1

[centreon-plugins-testing-noarch]
name=Centreon plugins repository. (UNSUPPORTED)
baseurl=https://packages.centreon.com/rpm-plugins/el9/testing/noarch/
enabled=0
gpgcheck=1
gpgkey=https://yum-gpg.centreon.com/RPM-GPG-KEY-CES
module_hotfixes=1

[centreon-plugins-unstable]
name=Centreon plugins repository. (UNSUPPORTED)
baseurl=https://packages.centreon.com/rpm-plugins/el9/unstable/$basearch/
enabled=0
gpgcheck=1
gpgkey=https://yum-gpg.centreon.com/RPM-GPG-KEY-CES
module_hotfixes=1

[centreon-plugins-unstable-noarch]
name=Centreon plugins repository. (UNSUPPORTED)
baseurl=https://packages.centreon.com/rpm-plugins/el9/unstable/noarch/
enabled=0
gpgcheck=1
gpgkey=https://yum-gpg.centreon.com/RPM-GPG-KEY-CES
module_hotfixes=1
EOF

Install the plugin:

dnf install -y centreon-plugin-Operatingsystems-Linux-Local.noarch

Debian 11 & 12

wget -O- https://apt-key.centreon.com | gpg --dearmor | tee /etc/apt/trusted.gpg.d/centreon.gpg > /dev/null 2>&1
echo "deb https://packages.centreon.com/apt-plugins-stable/ $(lsb_release -sc) main" | tee /etc/apt/sources.list.d/centreon-plugins.list
apt-get update

Install the plugin:

apt -y install centreon-plugin-operatingsystems-linux-local

Windows

On the hosts you want to monitor, download and execute the corresponding package for Windows. We suggest that you place the plugin at the same place as the Telegraf agent, for example C:\Program Files\InfluxData\telegraf\telegraf-1.30.3.

Step 3: Monitoring a host with the Telegraf agent

Create hosts using templates

Linux

On the central server, create hosts and apply to them the OS-Linux-Telegraf-Agent-custom template.

Windows

On the central server, create hosts and apply to them the OS-Windows-Telegraf-Agent-custom template.

Reload the agent

To let the agent know about the hosts you just created and start monitoring them, run the following command on the host:

Linux

systemctl restart telegraf 

Windows

telegraf.exe --service stop
telegraf.exe --service start