Centreon Monitoring Agent

Introduction

The Centreon Monitoring Agent (CMA) collects metrics and computes statuses on the servers it monitors, and sends them to Centreon. Centreon plugins as well as Nagios-compatible plugins can be used with this agent.

Limitations

The Centreon Monitoring Agent is in Beta Phase. The following limitations need to be considered :

• The scope of supported monitoring is limited, new (native) controls will be introduced in the final version.

Supported OSs

The CMA can be installed on and monitor the following OSs:

Linux

• Alma 8
• Alma 9
• Debian 11
• Debian 12
• Ubuntu 22.04 LTS

Windows

• Windows 10
• Windows 11
• Windows Server 2016
• Windows Server 2019
• Windows Server 2022

Step 1: Configure Centreon

Install the Monitoring Connector

Linux

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

Windows

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

Create the CMA connector

If your Centreon is on version 24.10.6 or newer, skip this step and move on to the next one.

If your Centreon is a version older than 24.10.6, you need to create the CMA connector your central server:

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

Parameter	Value
Connector Name	Centreon Monitoring Agent
Connector Description	Centreon Monitoring Agent
Command Line	opentelemetry --processor=centreon_agent --extractor=attributes --host_path=resource_metrics.resource.attributes.host.name --service_path=resource_metrics.resource.attributes.service.name
Used by command	Type Centreon-Monitoring-Agent and click Select all
Connector Status	Enabled

Configure Engine

Centreon Cloud or OnPrem 24.10.03 and newer

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. If the agent is not allowed to connect to the poller for security reasons (e.g. when the poller is in a DMZ), enable Connection initiated by poller. Then, in Host configurations, define all the hosts on which the agent will be installed. Here the certificates are optional, but if you use them, store them in the /etc/pki/ directory of the poller.

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

6. Deploy the configuration.

7. Restart the monitoring engine:

   systemctl restart centengine

The CMA can now communicate with Centreon. You can set up the monitoring of your hosts.

Versions older than 24.10.03

1. On the poller that will receive the data from the agent, install the centreon-engine-opentelemetry package.

2. On the poller that will receive the data from the agent, create the following file:

   touch /etc/centreon-engine/otl_server.json

3. Enter the following contents. This will allow the poller to receive the data that the agent will send.

The poller can work in both modes simultaneously (some agents connect to the poller, while the poller connects to some other agents).

No encryption, agent connects to poller

{
   "otel_server":{
      "host":"0.0.0.0",
      "port":4317
   },
   "max_length_grpc_log":0,
   "centreon_agent":{
      "check_interval":60,
      "export_period":10
   }
}

chown centreon-engine: /etc/centreon-engine/otl_server.json

Encryption, agent connects to poller

{
   "otel_server":{
      "host":"0.0.0.0",
      "port":4317,
      "encryption":true,
      "public_cert":"<CERTIFICATE PATH>",
      "private_key":"<KEY PATH>",
      "ca_certificate":"<CA PATH>"
   },
   "max_length_grpc_log":0,
   "centreon_agent":{
      "check_interval":60,
      "export_period":10
   }
}

No encryption, poller connects to agent

Use this configuration when the agent is not allowed to connect to the poller for security reasons (e.g. when the poller is in a DMZ). In this mode, the poller connects to the CMA.

{
   "max_length_grpc_log":0,
   "centreon_agent":{
      "check_interval":60,
      "export_period":15,
      "reverse_connections":[
         {
            "host":"<HOST ADDRESS>",
            "port":<PORT>
         }
      ]
   }
}

chown centreon-engine: /etc/centreon-engine/otl_server.json

• Enter the IP address of the CMA host in the host and port fields. This IP address must be reachable by the poller.
• The check_interval field is the period between two checks for the same service.

Encryption, poller connects to agent

Use this configuration when the agent is not allowed to connect to the poller for security reasons (e.g. when the poller is in a DMZ). In this mode, the poller connects to the CMA.

{
   "max_length_grpc_log":0,
   "centreon_agent":{
      "check_interval":60,
      "export_period":15,
      "reverse_connections":[
         {
            "host":"localhost",
            "port":4317,
            "encryption":true,
            "ca_certificate":"/tmp/ca_1234.crt",
            "ca_name":"<CA NAME>"
         }
      ]
   }
}

• Enter the IP address of the CMA host in the host and port fields. This IP address must be reachable by the poller.
• The check_interval field is the period between two checks for the same service.

Add a new Broker module

1. Go to Configuration > Pollers > Engine configuration, then click on the poller you want to monitor your resources.

2. On the Data tab, in the Broker module section, in the Multiple Broker Module parameter, click on Add a new entry.

3. Add the following entry :

   /usr/lib64/centreon-engine/libopentelemetry.so /etc/centreon-engine/otl_server.json

4. Deploy the configuration.

5. Restart the monitoring engine:

   systemctl restart centengine

The CMA can now communicate with Centreon. You can set up the monitoring of your hosts.

Step 2: Prepare the host

Download and install the agent

Linux

Centreon repository and agent install

Install the Centreon repository and agent using the following commands:

Alma / RHEL / Oracle Linux 8

dnf install -y dnf-plugins-core
dnf config-manager --add-repo https://packages.centreon.com/rpm-standard/24.10/el8/centreon-24.10.repo
dnf install  centreon-monitoring-agent

Alma / RHEL / Oracle Linux 9

dnf install -y dnf-plugins-core
dnf config-manager --add-repo https://packages.centreon.com/rpm-standard/24.10/el9/centreon-24.10.repo
dnf install  compat-openssl11 centreon-monitoring-agent

Debian 12

apt-get update
apt-get -y install lsb-release gpg wget
echo "deb https://packages.centreon.com/apt-standard-24.10-stable $(lsb_release -sc) main" | tee /etc/apt/sources.list.d/centreon.list
echo "deb https://packages.centreon.com/apt-plugins-stable/ $(lsb_release -sc) main" | tee /etc/apt/sources.list.d/centreon-plugins.list

Then, import the repository key :

wget -O- https://apt-key.centreon.com | gpg --dearmor | tee /etc/apt/trusted.gpg.d/centreon.gpg > /dev/null 2>&1

Then, install agent :

apt-get update
apt install centreon-monitoring-agent

• Configure centreon-monitoring-agent.

1. Modify the /etc/centreon-monitoring-agent/centagent.json file (4 cases):

No encryption, agent connects to poller

{
  "log_level":"info",
  "endpoint":"<IP POLLER>:4317",
  "host":"host_1",
  "log_type":"file",
  "log_file":"/var/log/centreon-monitoring-agent/centagent.log" 
}

Encryption, agent connects to poller

{
  "log_level":"info",
  "endpoint":"<IP POLLER>:4317",
  "host":"host_1",
  "log_type":"file",
  "log_file":"/var/log/centreon-monitoring-agent/centagent.log" ,
  "encryption":true,
  "ca_certificate":"/tmp/ca_1234.crt"
}

No encryption, poller connects to agent

{
  "log_level":"info",
  "endpoint":"0.0.0.0:4317",
  "host":"host_1",
  "log_type":"file",
  "log_file":"/var/log/centreon-monitoring-agent/centagent.log" ,
  "reversed_grpc_streaming":true
}

Encryption, poller connects to agent

{
  "log_level":"info",
  "endpoint":"0.0.0.0:4317",
  "host":"host_1",
  "log_type":"file",
  "log_file":"/var/log/centreon-monitoring-agent/centagent.log" ,
  "reversed_grpc_streaming":true,
  "encryption":true,
  "private_key":"/tmp/server_1234.key",
  "public_cert":"/tmp/server_1234.crt",
  "ca_certificate":"/tmp/ca_1234.crt"
}

In the host field, enter the name of the host to be monitored as you have entered it in the Centreon interface. If absent, the agent will use the machine's hostname.

Log configuration

You can configure two kinds of log output:

• file: the CMA logs into a file, the path is configured in the log_file option.
• stdout: standard output is used.

If you choose to log into a file, log rotation can be customized using the log_max_file_size and log_max_files options.

Allowed log levels are:

• off: no logs
• critical: critical errors
• error: all errors
• info: additional information
• debug: more information about connections
• trace: the most verbose trace level showing messages sent and received to the poller

2. Restart the CMA:

systemctl restart centagent

You can check that agent is running with:

systemctl status centagent

Windows

Download the CMA installer on every server you want to monitor.

Interactive mode

1. Start the installer (during the configuration, you can click on the (i) icons for help). If you choose to install centreon-plugins, the installer will try to download and install the latest version of the Centreon plugins. If it can't (no web connection, network issue...), a popup is displayed to ask confirmation before using embedded plugins.

• If yes: the plugins are installed
• If no: no plugins are installed

Results are displayed in the installer's window.

2. Configure the endpoint and the connection:

   • Host name in Centreon. This must be the host name you have defined in the Centreon interface.
   • In most cases (the agent connects to the poller), you have to enter the poller's endpoint. The correct format is <poller IP or DNS name>:port (OpenTelemetry listening port on the poller, usually 4317), for example 192.168.45.32:4317.
   • In case of a poller-initiated connection (the poller connects to the agent), you have to choose a host interface (0.0.0.0 for all interfaces) and the listening port on which poller will connect, usually 4317.

3. Configure logging options. You can configure two kinds of log output:

• file: the CMA logs into a file
• eventlog: the CMA logs in the event logs page

If you choose to log into a file, log rotation can be customized using the Max File Size and Max number of files options.

4. Configure encryption Encryption is activated by default. In case of a Poller-initiated connection, the private key file and certificate file are mandatory.

Silent mode (console)

In this mode, there is no interface. As this installer is not a console program, it returns immediately despite not having finished. You have to wait for a message telling you that all is finished. If you wnat to have an exit status, you can launch the installer in a powershell session and wait for the exit code. The exit code will be 0 if all is right.

flag	description
--install_cma	Set this flag if you want to install the Centreon Monitoring Agent
--install_plugins	Set this flag if you want to download and install the latest version of Centreon plugins
--install_embedded_plugins	Set this flag if you want to install Centreon plugins embedded in the installer (case of a host that cannot access the internet)
--hostname	The name of the host as defined in the Centreon interface.
--endpoint	IP address of DNS name of the poller the agent will connect to. In case of Poller-initiated connection mode, it is the interface and port on which the agent will accept connections from the poller. 0.0.0.0 means all interfaces. The format is (IP or DNS name):(port)
--reverse	Add this flag for Poller-initiated connection mode.
--log_type	event_log or file. In case of logging in a file, log_file param is mandatory
--log_level	can be off, critical, error, warning, debug or trace
--log_file	log files path.
--log_max_file_size	max file in Mo before rotate.
--log_max_files	max number of log files before delete. For the rotation of logs to be active, it is necessary that both parameters 'Max File Size' and 'Max number of files' are set.
--encryption	Add this flag for encrypt connection with poller.
--private_key	Private key file path. Mandatory if encryption and poller-initiated connection are active.
--public_cert	Public certificate file path. Mandatory if encryption and poller-initiated connection are active.
--ca	Trusted CA's certificate file path.
--ca_name	Expected TLS certificate common name (CN).
--reverse	Add this flag to make the agent accept connections from poller (agent in DMZ for example).

If you use --install_plugins option and plugins download fail, installer will install plugins embedded in the installer.

Allowed log levels are:

• off: no logs
• critical: critical errors
• error: all errors
• info: additional information
• debug: more information about connections
• trace: the most verbose trace level showing messages sent and received to the poller

As far as encryption is concerned, several cases are possible:

• reverse (Poller-initiated connection): the agent accepts connections from the poller. The agent needs a file containing the private key and a file containing the certificate (public key). Please note that the CN field in the certificate must match the name that will be used by the poller to connect to the host. For example, if you have entered myhostname in the CN, the poller must be able to connect to the host myhostname without using the IP address (a solution if myhostname is not in the DNS: add the IP myhostname mapping in the /etc/hosts file).
• not reverse: the agent connects to the poller You have two solutions for the certificate:
  • You have stored the poller's certificate in the Certificate Store, you have no file to fill in for the public key.
  • Otherwise, you need to provide the path to the file containing the public key of the poller's opentelemetry server. As with reverse mode, the DNS name that the agent will use to connect to the poller must be identical to the CN of the certificate. If this is not possible, you can add an IP collector_host_name mapping in the C:\Windows\System32\drivers\etc\hosts file.

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

dnf -y install dnf-plugins-core oracle-epel-release-el8
dnf config-manager --set-enabled ol8_codeready_builder

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

dnf install dnf-plugins-core
dnf install epel-release
dnf config-manager --set-enabled crb

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

apt update && apt install lsb-release ca-certificates apt-transport-https software-properties-common wget gnupg2 curl

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, plugins is yet installed by the centreon monitoring agent installer.

Step 3: Monitoring a host with the CMA

Create hosts using templates

Linux

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

Windows

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