OpenNMS Horizon install failed with CentOS Stream 9

Hi all

Trying to install latest ONMS Horizon on CentOS 9 in a VM.
VMware thinks the OS is version 5 or earlier, the same, I suppose, of the ONMS installation script, infact the startup script is using the not more present /etc/init.d directory in order to start ONMS …
I started ONMS directly with sudo -u opennms /opt/opennms/bin/opennms start … there is a solution for this in order to use systemctl to start it ?


Hello and welcome to our community. Do you mean CentOS 8 stream? I’m not aware of a CentOS 9 version exists? What installation instructions have you followed? We highly recommend the ones from our official documentation you can find here: Installation and configuration

Thanks Indigo

Yes, version 9 exist

I have followed the installation instructions from here

I suppose that the cause of the problem init.d instead of systemctl is the version 9 that is confused with early version.

Was able to reproduce the problem. Our systemd unit calls the init.d start script. I’ve documented the bug here in [NMS-13783] Systemd startup uses legacy SysV init script - The OpenNMS Issue Tracker

I was able to get the systemd unit to work by changing the path.

Edit the systemd unit:

sudo vi /etc/systemd/system/

Set the path to

ExecStart=/opt/opennms/bin/opennms -s start
ExecStop=/opt/opennms/bin/opennms stop

Reload systemd

sudo systemctl daemon-reload

Should now be able to enable the service on system boot and start the service with

sudo systemctl enable --now opennms

Hope this helps.

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Many Thanks Indigo

I will try your Workaround and I will let you know asap.


Hi Indigo

Workaround OK



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Ciao Indigo

May be is important to know that SELINUX must be disabled (default enabled on CentOS 9) otherwise the Discovery Scan does not work …
May be in permissive mode is the same but I have not tried.


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As far as I am aware, we have no support for running with SELinux enabled.

We also have zero testing to date running on CentOS 9 Stream. :slight_smile:

Thanks Indigo

It was only to inform other people of this “strange behavior”.