The SD-WAN Gateway is a pipeline architecture which processes bursts of traffic and bursts of high CPU are expected. The Gateway should be monitored for CPU cores that are spinning at 100%.

The following is an example Python script for monitoring the CPU usage:

#! /usr/bin/env python
"""
Check for CPUs spinning at 100%
"""
import re
import collections
import time
import sys
import json
import os
import subprocess
re_cpu = re.compile(r"^cpu\d+\s")
CPUStat = collections.namedtuple('CPUStat', ['user', 'nice', 'sys', 'idle'])
def get_stats():
        stats = open("/proc/stat").readlines()
        ret = {}
        for s in stats:
                if not re_cpu.search(s): continue
                s = s.split()
                ret[s[0]] = CPUStat(*[ int(v) for v in s[1:5]])
        return ret
def verify_dpdk_support():
    if os.path.isfile('/opt/vc/etc/dpdk.json'):
       with open("/opt/vc/etc/dpdk.json") as data:
           d=json.loads((data.read()))
       if "status" in  d.keys():
           return True if d['status'] is "Supported" else False
    else:
       return False
def another_verify_dpdk_support():
    if os.path.isfile('/opt/vc/bin/debug.py'):
        f=subprocess.check_output(["/opt/vc/bin/debug.py","--dpdk_ports_dump"])
        x=[r.split() for r in f.split('\n')]
	if len(x) <= 1:
		return False
	else:
                return True
    else:
	return False
dpdk_status=verify_dpdk_support() or another_verify_dpdk_support()
if __name__ == "__main__":
        try:
                stat1 = get_stats()
                time.sleep(3)
                stat2 = get_stats()
        except:
                print "UKNOWN - failed to get CPU stat: %s" % str(sys.exc_info()[1])
                sys.exit(3)
        busy_cpu_set = [ cpu for cpu in stat1 if (stat2[cpu].idle - stat1[cpu].idle)==0 ]
        if not busy_cpu_set:
                        print "OK - no spinning CPUs"
                        sys.exit(0)
        if dpdk_status == True:
           if "cpu1" in busy_cpu_set and len(busy_cpu_set) == 1:
                        print "OK - no spinning CPUs"
                        sys.exit(0)
           elif "cpu1" in busy_cpu_set:
                        busy_cpu_set.remove('cpu1')
                        print "CRITICAL - %s is at 100%%" % (",".join(busy_cpu_set))
                        sys.exit(2)
           else:
                        print busy_cpu_set,1
                        print "CRITICAL - %s is at 100%%" % (",".join(busy_cpu_set))
                        sys.exit(2)
        else:
                        print "CRITICAL - %s is at 100%%" % (",".join(busy_cpu_set))
                        sys.exit(2)