Hi there! I has a OPi zero board on armbian ubuntu os.  There is a python scrypt that ping server. Scrypt starts with my service.

service code:

[Unit]
Description=My Script Service
After=multi-user.target
[Service]
Type=simple
ExecStart=/usr/bin/sudo /usr/bin/python /root/test/qr2.py
RemainAfterExit=no
Restart=always
RestartSec=5
[Install]
WantedBy=multi-user.target

python ping server like:

try:
	os.system('ping ' + ip + ' -c 4')
    # or 
    # s.scall('ping ' + ip + ' -c 4 )
except:
	print 'ping error'

Sometimes If i start system after power supply scrypt is starting, but then hangs on ping function. In Htop (image) i can see ping process.  There are no python errors or exceptions. It just hangs. But if i use console command to ping  server ip while scrypt hans, it pings well.

If a starts scrypt manualy it works well, no hanging. Also if i execute reboot command in concole, then after restart scrypt do not hangs up. 

Tried to delay the execution?