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Monitoring with Checkmk CE

Checkmk is seamlessly integrated into the openITCOCKPIT interface. Hosts running the Checkmk agent or an SNMP exporter can thus be scanned using the openITCOCKPIT interface. For the purposes of this tutorial, we will be monitoring an Ubuntu Linux system.

Installing the Checkmk module for openITCOCKPIT

The Checkmk extension for openITCOCKPIT is provided as a module. Making such tools available in this way has the advantage of keeping the openITCOCKPIT core small and flexible.

openITCOCKPIT Community Licence is required

To get access to the community modules, you need to register your openITCOCKPIT instance using the free community licence.

Navigate to Management -> System Tools -> Package Manager and install the CheckmkModule

packagemanager install checkmk

Follow the instructions provided

packagemanager install instructions

The installation will be complete when you see the following message: Installation done. Please reload your openITCOCKPIT web interface.

Navigate back in your web browser and press Strg + R or Cmd + R to refresh the page.

The CheckmkModule should now be displayed as installed.

installed successful

Each module provides the ability to extend openITCOCKPIT's available permissions. By default, all permissions are granted to the Administrator user role.

If your current user is mapped to another user role, make sure you grant that role the appropriate permissions.

Navigate to Administration -> User Management -> Manage User Roles and select your user role.

checkmk userrole permissions grant

New permissions are not automatically granted (except for users who hold the Administrator user role). This is because not every user is allowed to use modules that, for example, were only installed for test or evaluation purposes.

Installing Checkmk Agent on the target system

As already mentioned, we use the Checkmk agent for monitoring remote systems.

To begin using this tool, you must first copy the Checkmk agent from your openITCOCKPIT server to the target system:

scp /opt/openitc/check_mk/agents/check_mk_agent.linux root@172.16.166.103:/usr/local/bin/check_mk_agent

All Checkmk agents for the various operating systems can be found here

/opt/openitc/check_mk/agents/

Now connect to the remote host via SSH

The Checkmk agent is not run as a daemon but rather by xinetd.

apt-get install xinetd
chmod +x /usr/local/bin/check_mk_agent

Security Notice

By default, Checkmk uses unencrypted plain text communication!

Next you need to copy the following configuration to /etc/xinetd.d/check_mk:

service check_mk
{
    type           = UNLISTED
    port           = 6556
    socket_type    = stream
    protocol       = tcp
    wait           = no
    user           = root
    server         = /usr/local/bin/check_mk_agent

    # configure the IP address(es) of your openITCOCKPIT server here:
    #only_from      = 127.0.0.1 10.0.20.1 10.0.20.2

    # Don't be too verbose. Don't log every check. This might be
    # commented out for debugging. If this option is commented out
    # the default options will be used for this service.
    log_on_success =

    disable        = no
}

To enable the new configuration, you must restart xinetd:

systemctl restart xinetd.service

That's everything that needs to be done on the remote host.

Scanning target host to create checks automatically

In the host systems’ context menu, select the Checkmk detection option.

checkmk discovery

Now select "Use the Checkmk agent for detection". Select Checkmk Agent as the data source.

checkmk remote discovery

Once the discovery process has completed, you can select any services you wish to monitor. Click Save to continue.

select checkmk services

To enable the new configuration, you must update the monitoring configuration.

Once this has been done, the system will begin monitoring the selected services a few seconds later. It will also generate graphs whenever this is possible.

checkmk services openitcockpit

Monitoring via SNMP with Checkmk

Many devices such as routers, switches, sensors or operating systems can be monitored via SNMP (Simple Network Management Protocol). Before continuing with this guide, make sure you have read the section entitled Monitoring with Checkmk.

Get SNMP data for the target device

Before you get started, please check whether your monitoring server is able to query SNMP data from the target device. The program snmpwalk can be used for this.

In this example we will query an Ubuntu Linux machine running snmpd version 2c and the community public.

snmpwalk -v2c -c public 172.16.166.103

You should then see output similar to this:

snmp walk example

If your system is not able to connect to the target system, check your firewall settings to see whether you are using the wrong SNMP version.

Monitoring a Linux host using SNMP via Checkmk

Select the Checkmk detection option in the context menu for the host system.

checkmk discovery snmp

Select the Enable SNMP option. The system will ask you for the required SNMP parameters. The SNMP configuration is saved on a per host basis, so you won't have to enter this data again. Then click Run detection to continue.

checkmk remote discovery

Once the discovery process has completed, you can select any services you would like to monitor. Click Next to continue.

checkmk snmp result

To enable the new configuration, you must update the monitoring configuration.

Once this has been done, the monitoring system will begin monitoring the selected services a few seconds later. It will also generate graphs whenever this is possible.

checkmk snmp services

Using description for SNMP interfaces

Depending on the device being monitored, it is advisable to use the SNMP description or alias instead of the index as the identifier for network interfaces.

By default, the index is used for monitoring interfaces. This can be easily recognised by the interface name.

Checkmk network interfaces monitored by index

If you would prefer to use the interface description instead of the index, a new Checkmk rule must be created.

To do this, create the file /opt/openitc/check_mk/etc/check_mk/conf.d/wato/interface_description_rule.mk with the following content:

globals().setdefault('inventory_if_rules', [])

inventory_if_rules = [
{'id': '35a60268-6aa0-4fb8-8fed-ba51e6b1d1e3', 'value': {'discovery_single': (True, {'item_appearance': 'descr', 'pad_portnumbers': True}), 'matching_conditions': (True, {})}, 'condition': {}},
] + inventory_if_rules

Any new interface checks you create will now use the description.

Checkmk network interfaces monitored by description

If you choose to use the alias instead of the (description) , you must use the following: 'item_appearance': 'alias' .

Create missing service templates for Checkmk.

Depending on the device on which you want to perform a discovery, you may find that the Options selection box is empty and the following text Before you can monitor the following services, a corresponding service template must be created. appears, followed by a table. If this is the case, you will have to create the missing service templates.

check mk snmp missing servicetemplates

Creating missing service templates

Open a new browser window and navigate to Monitoring -> Templates -> Service Templates and click + New.

Create a service template for hp_procurve_cpu

It is recommended you use the same name for a service template as Checkmk uses (MK Check). In this case, the MK Check is hp_procurve_cpu so we use CHECK_MK_HP_PROCURVE_CPU as the service template name. Set Checkmk templates as the template type. Disable Enable active checks, use check_none as the check command and set the Parameter from the table as ARG1.

Confirm with Create service templates

create missing checkmk snmp servicetemplate

Servicevorlagen Parameter Übersicht:

Parameter Value
Template name CHECK_MK_HP_PROCURVE_CPU
Service name CPU load on HP Procurve
Template type Checkmk templates
Enable active checks No
Check command check_none
ARG1 (80.0, 90.0)
Check period 24x7
Max. number of check attempts 1
Check interval 60
Retry interval 60

Repeat these steps for any service templates that may be missing.

Go to Check MK -> Mk Checks and click the + New button.

Set hp_procurve_cpu as Check name and select the corresponding service template CHECK_MK_HP_PROCURVE_CPU.

link servicetemplate to mk check

Now repeat this for all service templates.

check_mk_mkchecks_to_servicetemplates

Creating services

You are now able to create the services you want to monitor. Restart SNMP Discovery and select all desired services from the list that appears.

checkmk create new snmp services

To enable the new configuration, you must update the monitoring configuration.

checkmk snmp hp switch

Mixing surveillance methods

You can use both SNMP and the Checkmk agent at the same time without issue. To do this, select Enable Checkmk agent, select Checkmk Agent as the data soucre and Enable Enable SNMP as well as the SNMP version and your desired community.

checkmk remote discovery

Creating the Checkmk agent

To create a Checkmk agent, go to Monitoring -> Checkmk -> Checkmk Agents in the main menu.

Then click on the "New" button in the overview section.

Now select a container, give it a name and then enter the appropriate command line command. The command you use will refer to a Checkmk script on the openITCOCKPIT server.

Field Required Description
Container The container in which the Checkmk Agent is to be installed
Name Name of the Checkmk agent
Description Description of the Checkmk agent
Command line Command line command for the Checkmk agent script

Downloading Checkmk agents

You can easily download Checkmk agents via openITCOCKPIT by going to Monitoring -> Checkmk -> Checkmk Agents and then to the Agent downloads tab.

checkmk downloads