Infrastructure Monitoring

Sorry if this is the wrong forum
Searching for Saas Monitor service which monitor my servers which are sitting in different providers .
This monitor tool will take as less CPU as possible , and will send info about the server to main Dashboard.
The info I need is CPU / RAM / my servers status ( ps -ef ) .
When one of the rules is met I want to be notified by email/SMS
What do you recommend ?
Thanks

You can have a look at my Nagios plugins, also in this forum.
They are shell scripts; you can adapt their output for your needs.

The current output for Nagios consists of a text message and an exit status 0(OK), 1(WARNING), 2(CRITICAL), 3(UNKNOWN).
After the text message there can be a pipe symbol followed by a performance data sample.

Nagios runs the plugin scripts periodically, with arguments that are typically thresholds for WARNING and CRITICAL.
Nagios displays the output text and reacts on the output status (i.e. raises WARNING or CRITICAL alerts)..
And it records the performance data (in rrd tool). The Web GUI draws perfdata out of it.

For basic monitoring I recommend: check_load5.sh check_disks.sh check_vmem.sh