Install and use collectd-ping under CentOS 8 to monitor latency

Tracking the network latency of the servers’ network is not an easy job. Most monitoring software is capable to monitor the state of the server, but how to monitor the state of the connectivity and the network latency and even the Internet connectivity with some respectful addresses like 1.1.1.1 or 8.8.8.8? It should be easy to do it with ICMP and ping command but using the collectd daemon and one of its plugins offers collectd-ping from https://collectd.org/wiki/index.php/Plugin:Ping to save all the history in a time series back-end and using grafanahttps://grafana.com/ (or other graphs/histograms and etc software) to make graphs.
Using the collectd-ping plugin in conjunction with grafana may reach the similar effect as using the old and gold smokeping.
CentOS 7 included the collectd-ping plugin in its official repository, but in CentOS 8 the plugin is missing! Under Cent OS 8 the CentOS SIG OpsTools https://wiki.centos.org/SpecialInterestGroup/OpsTools includes the collectd-ping plugin in their repository. More on SIG and OpsTools may be obtained in the later page. In general, it is safe to use this repository it would not break user’s system.
Here is how to install and configure it. Real grafana examples are also included at the end.

The example here assumes there is a grafana server installed with influxdb backend.

STEP 1) Add OpsTools repository and install the collectd and collectd-ping.

The OpsTools repository is installed with centos-release-opstools package.
Here is what is going to install:

dnf install -y centos-release-opstools
dnf install -y collectd collectd-ping

Keep on reading!

collectd nginx plugin: curl_easy_perform failed because of selinux

Enabling the Nginx plugin for collectd under CentOS (or any other system using SELinux) might be confusing for a newbie. Most sources on the Internet would just install collectd-nginx:

yum install -y collectd-nginx

and configure it in the nginx.conf and collectd.conf. Still, the statistics might not work as expected, the collectd may not be able to gather statistics from the Nginx.

SELinux may prevent collectd (plugin) daemon to connect to Nginx and gather statistics from the Nginx stats page.

Checking the collectd log and it reports a problem:
Keep on reading!