We have a stand-alone application which has modules(API's) integrated within. Created JMeter tests to valid peak load and stress etc. Can we validate metrics such as availability, CPU Utilization? Bottom line would be targetting APM (Application Performance Management).
You can monitor your application resources utilization (CPU, RAM, Network, Disk, etc.) using JMeter PerfMon Plugin. It is capable of collecting 70+ metrics which can be plotted and visualized using Perfmon Metrics Collector listener.
You will need to install PerfMon Server Agent onto machine(s) you would like to monitor.
Another option is using SSHMon Listener (it is applicable only for SSH-enabled systems), in this case you will not need to install anything, however you will have to come up with the commands which will be run periodically and fetch the performance counters from the remote machine(s)