This example flow will let you monitor the Operating System process details for your Node-RED instance.
To make this work, you need to know the PID (Process Identifier) of your Node-RED instance. The easiest way to do that is to grab it on startup and add it to the global variables from settings.js. Add the following to your settings.js file & restart NR:
...
functionGlobalContext: {
'pid': process.pid
},
...
The data is taken from the /proc part of the Linux filing system for which you can find the specification in the Kernel docs. Specifically, it will tell you the details of the memory used by Node-RED. We are using /proc/<pid>/status here. However, there are plenty of other things you could also look up in a similar way as illustrated by this console command output:
$ ls /proc/28692/
autogroup cmdline cwd@ fdinfo/ maps mountstats oom_score root@ stack syscall
auxv comm environ io mem net/ oom_score_adj sched stat task/
cgroup coredump_filter exe@ limits mountinfo ns/ pagemap schedstat statm wchan
clear_refs cpuset fd/ map_files/ mounts oom_adj personality smaps status
$ cat /proc/28692/net/sockstat
sockets: used 172
TCP: inuse 18 orphan 0 tw 30 alloc 29 mem 3
UDP: inuse 9 mem 5
UDPLITE: inuse 0
RAW: inuse 0
FRAG: inuse 0 memory 0
$ cat /proc/28692/limits
Limit Soft Limit Hard Limit Units
Max cpu time unlimited unlimited seconds
Max file size unlimited unlimited bytes
Max data size unlimited unlimited bytes
Max stack size 8388608 unlimited bytes
Max core file size 0 unlimited bytes
Max resident set unlimited unlimited bytes
Max processes 7336 7336 processes
Max open files 4096 4096 files
Max locked memory 65536 65536 bytes
Max address space unlimited unlimited bytes
Max file locks unlimited unlimited locks
Max pending signals 7336 7336 signals
Max msgqueue size 819200 819200 bytes
Max nice priority 0 0
Max realtime priority 0 0
Max realtime timeout unlimited unlimited us