I am trying to use Kafka.
All configurations are done properly but when I try to produce message from console I keep getting the following error
WARN Err
For anyone trying to run kafka on kubernetes and running into this error, this is what finally solved it for me:
You have to either:
hostname
to the pod spec, that way kafka can find itself.or
hostPort
, then you need hostNetwork: true
and dnsPolicy: ClusterFirstWithHostNet
The reason for this is because Kafka needs to talk to itself, and it decides to use the 'advertised' listener/hostname to find itself, rather than using localhost. Even if you have a Service that points the advertised host name at the pod, it is not visible from within the pod. I do not really know why that is the case, but at least there is a workaround.
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: zookeeper-cluster1
namespace: default
labels:
app: zookeeper-cluster1
spec:
replicas: 1
selector:
matchLabels:
app: zookeeper-cluster1
template:
metadata:
labels:
name: zookeeper-cluster1
app: zookeeper-cluster1
spec:
hostname: zookeeper-cluster1
containers:
- name: zookeeper-cluster1
image: wurstmeister/zookeeper:latest
imagePullPolicy: IfNotPresent
ports:
- containerPort: 2181
- containerPort: 2888
- containerPort: 3888
---
apiVersion: v1
kind: Service
metadata:
name: zookeeper-cluster1
namespace: default
labels:
app: zookeeper-cluster1
spec:
type: NodePort
selector:
app: zookeeper-cluster1
ports:
- name: zookeeper-cluster1
protocol: TCP
port: 2181
targetPort: 2181
- name: zookeeper-follower-cluster1
protocol: TCP
port: 2888
targetPort: 2888
- name: zookeeper-leader-cluster1
protocol: TCP
port: 3888
targetPort: 3888
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: kafka-cluster
namespace: default
labels:
app: kafka-cluster
spec:
replicas: 1
selector:
matchLabels:
app: kafka-cluster
template:
metadata:
labels:
name: kafka-cluster
app: kafka-cluster
spec:
hostname: kafka-cluster
containers:
- name: kafka-cluster
image: wurstmeister/kafka:latest
imagePullPolicy: IfNotPresent
env:
- name: KAFKA_ADVERTISED_LISTENERS
value: PLAINTEXT://kafka-cluster:9092
- name: KAFKA_ZOOKEEPER_CONNECT
value: zookeeper-cluster1:2181
ports:
- containerPort: 9092
---
apiVersion: v1
kind: Service
metadata:
name: kafka-cluster
namespace: default
labels:
app: kafka-cluster
spec:
type: NodePort
selector:
app: kafka-cluster
ports:
- name: kafka-cluster
protocol: TCP
port: 9092
targetPort: 9092