What are the tools for monitoring servers for a beginner?

Question

Monitoring

What I found on the topic:
Which monitoring tool to choose?
Web service monitoring?
What DevOps practices (tools) do you use to deploy infrastructure?
The goal is to monitor services live and receive reactive feedback on the status of the system and its components, critical errors, failed connections to the server, etc.
It is quite natural that my eyes fled where to start and what to choose? What actually to monitor except for services?
Guide for beginners?

Answer 1

If monitoring is not your main task (for example, now the task is to monitor in order to receive information from the system, and then you need to return to other tasks) - use saas
Personally, I would recommend NewRelic and Datadog, although there are other saas solutions.
The first is a leader in saas application monitoring, and the second is in saas infrastructure monitoring, but both have both apm and infrastructure monitoring and work with logs.
If project monitoring is your main task, start digging towards
monitoring systems:
zabbix, TICK stack, prometheus, graphite, etc...
logging:
ELK stack, graylog, loki, etc..
as my own experience has shown, it is absolutely useless to advise any system to others. Well, you will do APM of the NewRelic level on your own for 10 years (and during this time they will make it even cooler)
Therefore: study how and with what other people monitor your set of applications / infrastructure and choose what suits you specifically