Just looking at my DietPi based PiHole install and I noticed that the dnsmasq service is dead. I've read around this and the FTL service seems to incorporate dnsmasq.
This answer seems to reinforce this Dnsmasq failed to start.
My question is therefore, should the dnsmasq service be disabled so it never tries to start?
DietPi-PiHole:~# systemctl status dnsmasq
β dnsmasq.service - dnsmasq - A lightweight DHCP and caching DNS server
Loaded: loaded (/lib/systemd/system/dnsmasq.service; disabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Sun 2019-01-06 20:43:11 GMT; 12s ago
Process: 34511 ExecStart=/etc/init.d/dnsmasq systemd-exec (code=exited, status=2)
Process: 34508 ExecStartPre=/usr/sbin/dnsmasq --test (code=exited, status=0/SUCCESS)
Jan 06 20:43:11 DietPi-PiHole systemd[1]: Starting dnsmasq - A lightweight DHCP and caching DNS server...
Jan 06 20:43:11 DietPi-PiHole dnsmasq[34508]: dnsmasq: syntax check OK.
Jan 06 20:43:11 DietPi-PiHole dnsmasq[34511]: dnsmasq: failed to create listening socket for port 53: Address already in use
Jan 06 20:43:11 DietPi-PiHole systemd[1]: dnsmasq.service: Control process exited, code=exited status=2
Jan 06 20:43:11 DietPi-PiHole systemd[1]: Failed to start dnsmasq - A lightweight DHCP and caching DNS server.
Jan 06 20:43:11 DietPi-PiHole systemd[1]: dnsmasq.service: Unit entered failed state.
Jan 06 20:43:11 DietPi-PiHole systemd[1]: dnsmasq.service: Failed with result 'exit-code'.
DietPi-PiHole:~# systemctl status pihole-FTL.service
β pihole-FTL.service - LSB: pihole-FTL daemon
Loaded: loaded (/etc/init.d/pihole-FTL; generated; vendor preset: enabled)
Active: active (running) since Sun 2019-01-06 00:17:14 GMT; 20h ago
Docs: man:systemd-sysv-generator(8)
Process: 59209 ExecStop=/etc/init.d/pihole-FTL stop (code=exited, status=0/SUCCESS)
Process: 59295 ExecStart=/etc/init.d/pihole-FTL start (code=exited, status=0/SUCCESS)
Tasks: 7 (limit: 9830)
CGroup: /system.slice/pihole-FTL.service
ββ59384 /usr/bin/pihole-FTL