How to organize monitoring of 3 servers?

Question

Monitoring

There are 3 VDS servers
. You need to monitor online CPU load, memory load and free disk space and record statistics for a certain period (at least 1 day).
That is, I need to be able to go to the web interface and at any time see the current situation.
If the allowed value is exceeded (disk space runs out, etc.) - sending a letter to the mail.
I tried munin, nagios, zabbix, cacti - they are all monstrous, large, with a bunch of extra features.
I want something as simple as possible. I will also consider some cloud services.

Answer 1

monit + munin

Answer 2

Zabbix.))))
I want something as simple as possible. I will also consider some cloud services.
There is an out of the box version. mount the image and work.