rtop is a simple, agent-less, remote server monitoring tool that works over plain SSH. It does not need any software to be installed on the server that you want to monitor. It works by establishing an SSH session, and running commands on the remote server to collect system metrics.
It keeps refreshing the information every few seconds, like the other *top utilities. This is how it looks like:
rtop 1.0 - (c) 2015 RapidLoop - MIT Licensed - http://rtop-monitor.org rtop monitors server statistics over an ssh connection Usage: rtop [-i private-key-file] [user@]host[:port] [interval] -i private-key-file PEM-encoded private key file to use (default: ~/.ssh/id_rsa if present) [user@]host[:port] the SSH server to connect to, with optional username and port interval refresh interval in seconds (default: 5)
go get github.com/rapidloop/rtop
rtop should be able to monitor any modern Linux distro, and should be able to run on all platforms that Go supports. It runs with some limitations on Windows too.
You might also like the related project rtop-bot, which has a Slack and HipChat bot frontend for rtop.