I have prepared two services a.service and b.service. The a.service run using a.timer.
a.service
[Unit]
Description=service a
After=network-online.target
Wants=network-online.target
[Service]
Type=simple
#restart on failure and tries 5 times. If fail in all, then reboot the system
ExecStart=/usr/bin/python /home/pi/.clar/a.py
Restart=on-failure
RestartSec=15
StartLimitBurst=5
StartLimitInterval=2min
StartLimitAction=reboot
a.timer
[Unit]
Description=10minute timer
[Timer]
# start this 20 Sec after boot:
OnBootSec=20
# ... and then every 10 minute:
OnUnitActiveSec=10m
[Install]
WantedBy=multi-user.target
b.service
[Unit]
Description=b service
After=a.service
[Service]
Type=simple
#restart on failure and tries 5 times. If fail in all, then reboot the system
ExecStartPre=/usr/bin/python /home/pi/.clar/c.py
ExecStart=/usr/bin/python /home/pi/.clar/b.py
Restart=on-failure
RestartSec=15
StartLimitBurst=5
StartLimitInterval=2min
StartLimitAction=reboot
[Install]
WantedBy=multi-user.target
As my configuration a.service will start after 20sec from boot up and b.service should run after a.service.
But in reallity b.service is started before the a.service. I have searched google and I tried by adding both Recquires=aRequires=a.service and Wants=a.service in b.service unit section. But neither one helped me.
I didn't understand the After working. Is there anything else to add in the configuration?