Nagios Support Forum

Figure out what packages contain python3-rrdtool and rrdtool-devel and make them available to your software install utility.

Can you ping the hosts?

Have a look here: https://exchange.nagios.org/directory/addons/notifications-addons/ I'm sure there's a better doc somewhere but you could use this to set up to use ntfy.sh. https://assets.nagios.com/downloads/nagiosxi/docs/Integrating-Slack-With-Nagios-XI.pdf Start at the installing the script step...

RHEL 10 has mysql 8.4 so you can expect it's fine with Nagios.

Yes

It looks like this is the first error:
Base class package "Class::Accessor::Fast" is empty.

The following should in theory install it:
sudo dnf install perl-class-accessor

If that installs, you may need other modules as well if the install fails again. Install them in the same way.

The OP might try investigating the difference between the old hosts and the new ones created from the unconfigured objects.

Its probably best to not use unix reserved characters.

Have a look here: https://exchange.nagios.org/directory/p ... tions/sms/

Dumb question but did you apply the changes in ccm?