I'm running PiHole on an Ubuntu 20.04.4 LTS VMware VM and every so often it'll stop responding to DNS requests and DHCP DISCOVER messages, a reboot fixes it every time...For a bit, finally got around to doing something about it rather than rebooting. I kicked up a new VM last night to see if something was borked with my previous install and lo and behold it died again tonight. The logs show a ton of "DNSMASQ_WARN Ignoring duplicate dhcp-option 23" messages along with DHCPREBIND messages but I'm not sure if that's what's killing it or not.
Pi-hole version is v5.9 (Latest: v5.9)
AdminLTE version is v5.11 (Latest: v5.11)
FTL version is v5.14 (Latest: v5.14)
I do have an additional file in dnsmasq.d (99-pihole-dhcp.conf) to issue both my primary and secondary PiHole servers via DHCP.
dhcp-option=6,192.168.2.7,192.168.22.2
dhcp-option=option6:dns-server,[(sanitized):11e::7],[(sanitized):11e:5::2]
I also have LibreNMS monitoring this VM and Pi-Hole via SNMP but I also have it monitoring my "backup" PiHole server running on a Raspberry Pi without issue.
My MikroTik RB4011 is also issuing SLAAC for IPv6, other than that it's the only other "DHCP" thing on this broadcast domain so I'm not 100% sure where the duplicate DHCP option 23 is coming from.
Several "Ignoring duplicate dhcp-option 23" and "Error while trying to close database: database is locked" entries in pihole-FTL.log. The disk isn't out of disk space and the FTL DB doesn't seem overly big considering this is a new VM.
root@pi-hole-primary:~# df -h /
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/ubuntu--vg-ubuntu--lv 62G 7.3G 51G 13% /
root@pi-hole-primary:~# ls -lh /etc/pihole/*.db
-rw-rw-r-- 1 pihole pihole 23M Mar 6 09:55 /etc/pihole/gravity.db
-rw-rw-r-- 1 pihole pihole 5.7M Mar 6 09:55 /etc/pihole/gravity_old.db
-rw-r--r-- 1 pihole pihole 2.7M Mar 6 09:46 /etc/pihole/macvendor.db
-rw-rw-r-- 1 pihole pihole 24M Mar 8 02:48 /etc/pihole/pihole-FTL.db
Debug Token:
https://tricorder.pi-hole.net/HPobjV8K/