Razvan,
The secondary kea server is on a completely seperate computer. My home network
infrastructure consists of on decent (ish) server and several, old, second hand
computers I bought cheap. One of these runs the secondary server. It binds to
the standard ethernet port of that machine and then services the network via
the router. As I said the main server is connected to the router through br0.
It connects to the internet and to other computers on the network (e.g. it
shares files via samba). It even contacts the secondary dhcp server to ask it
to turn off when I restart kea-dhcp4-server. It then just doesn't offer leases.
The VMs connect to the router via the Bridged Network and then receive dhcp
DORA from the secondary server via the router, so long as the main server is
off and failover is complete.
There are no files at all in /var/log/kea. There is also no fles called
kea-dhcp4.log in /var/log, where the config file indicates it should be. I
think my logging parameters are screwed up, perhaps I need to change the debug
level or severity, perhaps there is a stupid typo.
Regards
Stuart MacGregor
On 21/2/26 20:10, Razvan Becheriu wrote:
Hi,
How is it that the vms acquire ip using secondary server? does the secondary
bind on the same interface at the same time?
Logs should be under /kea/install/path/var/log/kea
I think that only one of your servers successfully binds to the interface and
because the server uses reuse port/address the secondary if starts second will
receive traffic.
________________________________
From: Stuart<[email protected]>
To: kea-users<[email protected]>
Date: Saturday, 21 February 2026 3:31 AM EET
Subject: [Kea-users] Kea DHCP4 not working on newly configured bridged network
Good Morning,
I am running Ubuntu 24.04, Kea 2.4.1. I have been using Kea without major
issues for a year or two, isc-dhcp for a couple of years prior. During recent
kernel updates I decided I was sick of Virtualbox compatibility issues, so I
created a bridged network so that I could move my vms (Nextcloud, Stork) to
KVM. I am somewhat incompetent, but after about 100 attempts I have managed to
setup a bridged network that connects my server to the rest of the network and
to the internet. My new KVM VMs are joining the network as if they were real
devices. My problem is my kea DHCP4 server. I guess have done something stupid,
either with selecting the interface in kea-dhcp4.conf or with configuring my
bridged network (br0). At this stage, when I start kea-dhcp4-server, it
communicates to my HA standby to to take control of DHCP but then completely
fails to provide ip addresses itself. So, the network currently looks like this:
dad@macserver:~$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group
default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host noprefixroute
valid_lft forever preferred_lft forever
2: enp34s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master
br0 state UP group default qlen 1000
link/ether 2c:f0:5d:2d:88:35 brdff:ff:ff:ff:ff:ff
3: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group
default qlen 1000
link/ether 42:4c:23:6c:4d:7f brdff:ff:ff:ff:ff:ff
inet 192.168.1.104/23 brd 192.168.1.255 scope global noprefixroute br0
valid_lft forever preferred_lft forever
inet6fe80::e54c:73f4:f662:95fb/64 scope link noprefixroute
valid_lft forever preferred_lft forever
4: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state
DOWN group default qlen 1000
link/ether 52:54:00:5b:e6:4e brdff:ff:ff:ff:ff:ff
inet 192.168.100.1/24 brd 192.168.100.255 scope global virbr0
valid_lft forever preferred_lft forever
5: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br0
state UNKNOWN group default qlen 1000
link/etherfe:00:27:dc:06:7e brdff:ff:ff:ff:ff:ff
inet6fe80::fc00:27ff:fedc:67e/64 scope link
valid_lft forever preferred_lft forever
6: vnet1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br0
state UNKNOWN group default qlen 1000
link/etherfe:54:00:80:eb:73 brdff:ff:ff:ff:ff:ff
inet6fe80::fc54:ff:fe80:eb73/64 scope link
valid_lft forever preferred_lft forever
The key sections (eliminating all my lease reservations and such) of my
dhcp4.conf look like this:
{
"Dhcp4": {
"interfaces-config": {
"interfaces": [ "br0" ]
},
"control-socket": {
"socket-type": "unix",
"socket-name": "/run/kea/kea4-ctrl-socket"
},
"lease-database": {
"type": "memfile",
"lfc-interval": 3600
},
"multi-threading": {
"enable-multi-threading": true,
"thread-pool-size": 2,
"packet-queue-size": 14
},
"client-classes": [
{
"name": "homeauto"
},
{
"name": "normal",
"test": "not member('homeauto')"
}
],
"option-data": [
{
"space": "dhcp4",
"name": "domain-name",
"code": 15,
"data": "skfaf.servesarcasm.com"
},
{
"space": "dhcp4",
"name": "domain-name-servers",
"code": 6,
"data": "192.168.1.1"
},
{
"space": "dhcp4",
"name": "broadcast-address",
"code": 28,
"data": "192.168.1.255"
},
{
"space": "dhcp4",
"name": "routers",
"code": 3,
"data": "192.168.1.1"
},
{
"space": "dhcp4",
"name": "subnet-mask",
"code": 1,
"data": "255.255.254.0"
}
],
"valid-lifetime": 43200,
"renew-timer": 21600,
"rebind-timer": 32400,
"expired-leases-processing": {
"reclaim-timer-wait-time": 3600,
"hold-reclaimed-time": 172800,
"max-reclaim-leases": 0,
"max-reclaim-time": 0
},
"dhcp-ddns": {
"enable-updates": false
},
"authoritative": true,
"hooks-libraries": [
{
"library": "/usr/lib/x86_64-linux-gnu/kea/hooks/libdhcp_lease_cmds.so"
},
{
"library": "/usr/lib/x86_64-linux-gnu/kea/hooks/libdhcp_stat_cmds.so"
},
{
"library": "/usr/lib/x86_64-linux-gnu/kea/hooks/libdhcp_ha.so",
"parameters": {
"high-availability": [ {
"this-server-name": "macserver",
"mode": "hot-standby",
"heatbeat-delay": 10000,
"max-response-delay": 60000,
"max-ack-delay": 5000,
"max-unacked-clients": 5,
"sync-timeout": 60000,
"multi-threading": {
"enable-multi-threading": true,
"http-dedicated-listener": true,
"http-listener-threads": 0,
"http-client-threads": 0
},
"peers": [
{
"name": "macserver",
"url":"http://192.168.1.104:8003/";,
"role": "primary"
},
{
"name": "oldhp",
"url":"http://192.168.1.110:8003/";,
"role": "standby"
}
]
} ]
}
}
],
"shared-networks": [
{
"name": "macnet",
"subnet4": [
{
"id": 1,
"subnet": "192.168.1.0/24",
"pools": [
{
"pool": "192.168.1.124 - 192.168.1.198",
"client-class": "normal"
}
],
"option-data": [
{
"space": "dhcp4",
"name": "routers",
"code": 3,
"data": "192.168.1.1"
}
]
},
{
"id": 2,
"subnet": "192.168.0.0/23",
"pools": [
{
"pool": "192.168.0.150 - 192.168.0.175",
"client-class": "homeauto"
}
],
"option-data": [
{
"space": "dhcp4",
"name": "routers",
"code": 3,
"data": "192.168.1.1"
},
{
"space": "dhcp4",
"name": "domain-name-servers",
"code": 6,
"data": "192.168.1.1"
}
]
}
]
}
],
"loggers": [
{
"name": "kea-dhcp4",
"output_options": [
{
"output": "/var/log/kea-dhcp4.log",
"maxsize": 2048000,
"maxver": 4
}
],
"severity": "INFO",
"debuglevel": 0
}
]
}
}
I changed my "interface" to "br0" because my previous setup (exerp below)
stopped working when I started the br0 network.
{
"Dhcp4": {
"interfaces-config": {
"interfaces": [ "enp34s0" ]
Changing the interface to "br0" has had exactly no effect.
I realise that I have missed something fundamental and I am wasting your valuable
time. However I have been trying to sort this out for days (in whatever spare time
is available) and I have acheived nothing. Each time I start kea-dhcp-server on my
main server it appears in Stork with no errors, systemd says its running fine and
my HA standby stops providing dhcp. Unfortunately if I then turn on a device it
simply does not receive an ip lease. If I turn off DHCP on the main server then
eventually the standby starts takes over dhcp again and network functions return to
normal (though this takes a very long time & sometimes requires a restart of
kea-dhcp4-server on the stanby server, perhaps another error to fix later). Even my
new VMs receive ips seamlessly from the standby server.
If you need to see some logs, please tell me where I can retreive them because
I haven't been able to work that out either (I think I need to change my
logging parameters in kea-dhcp4.conf). I used Wireshark to capture network coms
before and after turning on the main dhcp server but I then realised that I was
too stupid/ignorant to work out what was going on from the output. I can
provided the Wireshark output, but it is a large file (ran it for too long and
filtered it poorly, I think) that I won't inflict on you unless you wish it.
Please give me some ideas of what I have to do to troubleshoot/fix this.
Regards
Stuart MacGregor
--
ISC funds the development of this software with paid support subscriptions.
Contact us athttps://www.isc.org/contact/ for more information.
To unsubscribe visithttps://lists.isc.org/mailman/listinfo/kea-users.
[email protected]
