Deploying a dhcpd server - kubernetes

Question

I'm trying to deploy a DHCP server in a pod on my Kubernetes cluster.
I've created the following resources:
$ cat dhcpd-deployment.yaml
kind: Deployment
metadata:
name: dhcpd
namespace: kube-mngt
spec:
selector:
matchLabels:
app: dhcpd
replicas: 1
template:
metadata:
labels:
app: dhcpd
spec:
nodeSelector:
kubernetes.io/hostname: neo1
containers:
- name: dhcpd
image: 10.0.100.1:5000/dhcpd:latest
volumeMounts:
- name: dhcpd-config
mountPath: /etc/dhcp
volumes:
- name: dhcpd-config
persistentVolumeClaim:
claimName: dhcpd-config-volume-claim
$ kubectl create -f dhcpd-deployment.yaml
$ cat dhcpd-service.yaml
apiVersion: v1
kind: Service
metadata:
name: dhcpd
namespace: kube-mngt
spec:
selector:
app: dhcpd
ports:
- name: dhcp
protocol: UDP
port: 67
targetPort: 67
$ kubectl create -f dhcpd-service.yaml
Everything is created successfully, pod and service but unfortunately, the DHCPD pod does not receive any packet on UDP port 67.
Did I miss something?

Answer 1

I've found the solution to make the dhcpd pod working well.
The example below is to server a external network outside of the k8s service network (clusterIPs).
The dhcp configuration is like following:
include "/etc/dhcp/dhcpd-options.conf";
subnet 192.168.0.0 netmask 255.255.0.0 {}
# management network
subnet 10.0.0.0 netmask 255.255.0.0 {
option routers 10.0.255.254;
option broadcast-address 10.0.255.255;
next-server 10.0.100.6;
include "/etc/dhcp/lease-bmc.conf";
include "/etc/dhcp/lease-node.conf";
}
The k8s service is as following:
$ cat dhcpd-service.yaml
apiVersion: v1
kind: Service
metadata:
name: dhcpd
namespace: kube-mngt
spec:
selector:
app: dhcpd
ports:
- protocol: UDP
port: 67
targetPort: 67
externalIPs:
- 10.0.100.5
Then, configure the switch (interface vlan X) to specify an helper-address that point the the dhcp server (in our case, 10.0.100.5)
interface Vlan1
ip address 10.0.255.254 255.255.0.0 secondary
ip address 10.0.0.1 255.255.0.0
ip helper-address 10.0.100.5
!