无法连接到 kafka 代理 [英] Not able to connect to kafka brokers

问题描述

我已经部署了https://github.com/confluentinc/cp-helm-charts/tree/master/charts/cp-kafka 在我的本地 k8s 集群上.我正在尝试使用带有 nginx 的 TCP 控制器来公开它.

I've deployed https://github.com/confluentinc/cp-helm-charts/tree/master/charts/cp-kafka on my on prem k8s cluster. I'm trying to expose it my using a TCP controller with nginx.

我的 TCP nginx 配置映射看起来像

My TCP nginx configmap looks like

data:
  "<zookeper-tcp-port>": <namespace>/cp-zookeeper:2181
  "<kafka-tcp-port>": <namespace>/cp-kafka:9092

我已经在我的 nginx 入口控制器中做了相应的条目

And i've made the corresponding entry in my nginx ingress controller

  - name: <zookeper-tcp-port>-tcp
    port: <zookeper-tcp-port>
    protocol: TCP
    targetPort: <zookeper-tcp-port>-tcp
  - name: <kafka-tcp-port>-tcp
    port: <kafka-tcp-port>
    protocol: TCP
    targetPort: <kafka-tcp-port>-tcp

现在我正在尝试连接到我的 kafka 实例.当我尝试使用 kafka 工具连接到 IP 和端口时，我收到错误消息

Now I'm trying to connect to my kafka instance. When i just try to connect to the IP and port using kafka tools, I get the error message

Unable to determine broker endpoints from Zookeeper.
One or more brokers have multiple endpoints for protocol PLAIN...
Please proved bootstrap.servers value in advanced settings
[<cp-broker-address-0>.cp-kafka-headless.<namespace>:<port>][<ip>]

当我进入时，我假设正确的经纪人地址(我已经尝试了所有这些...)我超时了.没有来自 nginx 控制器的日志，例外

When I enter, what I assume are the correct broker addresses (I've tried them all...) I get a time out. There are no logs coming from the nginx controler excep

[08/Apr/2020:15:51:12 +0000]TCP200000.000
[08/Apr/2020:15:51:12 +0000]TCP200000.000
[08/Apr/2020:15:51:14 +0000]TCP200000.001

从 pod kafka-zookeeper-0 我得到了很多

From the pod kafka-zookeeper-0 I'm gettting loads of

[2020-04-08 15:52:02,415] INFO Accepted socket connection from /<ip:port> (org.apache.zookeeper.server.NIOServerCnxnFactory)
[2020-04-08 15:52:02,415] WARN Unable to read additional data from client sessionid 0x0, likely client has closed socket (org.apache.zookeeper.server.NIOServerCnxn)
[2020-04-08 15:52:02,415] INFO Closed socket connection for client /<ip:port>  (no session established for client) (org.apache.zookeeper.server.NIOServerCnxn)

虽然我不确定这些与它有什么关系?

Though I'm not sure these have anything to do with it?

对我做错了什么有什么想法吗?提前致谢.

Any ideas on what I'm doing wrong? Thanks in advance.

推荐答案

TL;DR:

• 在部署之前，将 cp-kafka/values.yaml 中的值 nodeport.enabled 更改为 true.
• 更改 TCP NGINX Configmap 和 Ingress 对象中的服务名称和端口.
• 将 kafka 工具上的 bootstrap-server 设置为 :31090

• Change the value nodeport.enabled to true inside cp-kafka/values.yaml before deploying.
• Change the service name and ports in you TCP NGINX Configmap and Ingress object.
• Set bootstrap-server on your kafka tools to <Cluster_External_IP>:31090

说明:

Headless Service 与 StatefulSet 一起创建.创建的服务将不获得clusterIP，而是简单地包含一个端点列表.然后使用这些 Endpoints 以以下形式生成特定于实例的 DNS 记录:-...svc.cluster.local

The Headless Service was created alongside the StatefulSet. The created service will not be given a clusterIP, but will instead simply include a list of Endpoints. These Endpoints are then used to generate instance-specific DNS records in the form of: <StatefulSet>-<Ordinal>.<Service>.<Namespace>.svc.cluster.local

它为每个 Pod 创建一个 DNS 名称，例如:

It creates a DNS name for each pod, e.g:

[ root@curl:/ ]$ nslookup my-confluent-cp-kafka-headless
Server:    10.0.0.10
Address 1: 10.0.0.10 kube-dns.kube-system.svc.cluster.local

Name:      my-confluent-cp-kafka-headless
Address 1: 10.8.0.23 my-confluent-cp-kafka-1.my-confluent-cp-kafka-headless.default.svc.cluster.local
Address 2: 10.8.1.21 my-confluent-cp-kafka-0.my-confluent-cp-kafka-headless.default.svc.cluster.local
Address 3: 10.8.3.7 my-confluent-cp-kafka-2.my-confluent-cp-kafka-headless.default.svc.cluster.local

• 这就是使这些服务在集群内相互连接的原因.

我经历了大量的反复试验，直到我意识到它应该如何工作.基于您的 TCP Nginx Configmap，我相信您遇到了同样的问题.

I've gone through a lot of trial and error, until I realized how it was supposed to be working. Based your TCP Nginx Configmap I believe you faced the same issue.

• Nginx ConfigMap 询问for: : "/:".
• 我意识到您不需要公开 Zookeeper，因为它是一项内部服务，由 kafka 代理处理.
• 我还意识到您正试图公开 cp-kafka:9092，它是无头服务，也仅在内部使用，正如我上面所解释的.
• 为了获得外部访问您必须将参数 nodeport.enabled 设置为 true，如下所述:外部访问参数.
• 它在图表部署期间为每个 kafka-N pod 添加一项服务.
• 然后您将配置映射更改为映射到其中之一:
• The Nginx ConfigMap asks for: <PortToExpose>: "<Namespace>/<Service>:<InternallyExposedPort>".
• I realized that you don't need to expose the Zookeeper, since it's a internal service and handled by kafka brokers.
• I also realized that you are trying to expose cp-kafka:9092 which is the headless service, also only used internally, as I explained above.
• In order to get outside access you have to set the parameters nodeport.enabled to true as stated here: External Access Parameters.
• It adds one service to each kafka-N pod during chart deployment.
• Then you change your configmap to map to one of them:

data:
"31090": default/demo-cp-kafka-0-nodeport:31090

请注意，创建的服务具有选择器 statefulset.kubernetes.io/pod-name: demo-cp-kafka-0 这是该服务识别它打算连接的 pod 的方式.

Note that the service created has the selector statefulset.kubernetes.io/pod-name: demo-cp-kafka-0 this is how the service identifies the pod it is intended to connect to.

• 编辑 nginx-ingress-controller:

- containerPort: 31090
  hostPort: 31090
  protocol: TCP

• 将您的 kafka 工具设置为 :31090

复制:- 在 cp-kafka/values.yaml 中编辑的片段:

Reproduction: - Snippet edited in cp-kafka/values.yaml:

nodeport:
  enabled: true
  servicePort: 19092
  firstListenerPort: 31090

• 部署图表:

$ helm install demo cp-helm-charts
$ kubectl get pods
NAME                                       READY   STATUS    RESTARTS   AGE
demo-cp-control-center-6d79ddd776-ktggw    1/1     Running   3          113s
demo-cp-kafka-0                            2/2     Running   1          113s
demo-cp-kafka-1                            2/2     Running   0          94s
demo-cp-kafka-2                            2/2     Running   0          84s
demo-cp-kafka-connect-79689c5c6c-947c4     2/2     Running   2          113s
demo-cp-kafka-rest-56dfdd8d94-79kpx        2/2     Running   1          113s
demo-cp-ksql-server-c498c9755-jc6bt        2/2     Running   2          113s
demo-cp-schema-registry-5f45c498c4-dh965   2/2     Running   3          113s
demo-cp-zookeeper-0                        2/2     Running   0          112s
demo-cp-zookeeper-1                        2/2     Running   0          93s
demo-cp-zookeeper-2                        2/2     Running   0          74s

$ kubectl get svc
NAME                         TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)             AGE
demo-cp-control-center       ClusterIP   10.0.13.134   <none>        9021/TCP            50m
demo-cp-kafka                ClusterIP   10.0.15.71    <none>        9092/TCP            50m
demo-cp-kafka-0-nodeport     NodePort    10.0.7.101    <none>        19092:31090/TCP     50m
demo-cp-kafka-1-nodeport     NodePort    10.0.4.234    <none>        19092:31091/TCP     50m
demo-cp-kafka-2-nodeport     NodePort    10.0.3.194    <none>        19092:31092/TCP     50m
demo-cp-kafka-connect        ClusterIP   10.0.3.217    <none>        8083/TCP            50m
demo-cp-kafka-headless       ClusterIP   None          <none>        9092/TCP            50m
demo-cp-kafka-rest           ClusterIP   10.0.14.27    <none>        8082/TCP            50m
demo-cp-ksql-server          ClusterIP   10.0.7.150    <none>        8088/TCP            50m
demo-cp-schema-registry      ClusterIP   10.0.7.84     <none>        8081/TCP            50m
demo-cp-zookeeper            ClusterIP   10.0.9.119    <none>        2181/TCP            50m
demo-cp-zookeeper-headless   ClusterIP   None          <none>        2888/TCP,3888/TCP   50m

• 创建 TCP 配置映射:

$ cat nginx-tcp-configmap.yaml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: tcp-services
  namespace: kube-system
data:
  31090: "default/demo-cp-kafka-0-nodeport:31090"

$ kubectl apply -f nginx-tcp.configmap.yaml
configmap/tcp-services created

• 编辑 Nginx 入口控制器:

$ kubectl edit deploy nginx-ingress-controller -n kube-system

$kubectl get deploy nginx-ingress-controller -n kube-system -o yaml
{{{suppressed output}}}
        ports:
        - containerPort: 31090
          hostPort: 31090
          protocol: TCP
        - containerPort: 80
          name: http
          protocol: TCP
        - containerPort: 443
          name: https
          protocol: TCP

• 我的入口在 IP 35.226.189.123 上，现在让我们尝试从集群外部连接.为此，我将连接到另一个具有 minikube 的 VM，以便我可以使用 kafka-client pod 进行测试:
• My ingress is on IP 35.226.189.123, now let's try to connect from outside the cluster. For that I'll connect to another VM where I have a minikube, so I can use kafka-client pod to test:

user@minikube:~$ kubectl get pods
NAME           READY   STATUS    RESTARTS   AGE
kafka-client   1/1     Running   0          17h

user@minikube:~$ kubectl exec kafka-client -it -- bin/bash

root@kafka-client:/# kafka-console-consumer --bootstrap-server 35.226.189.123:31090 --topic demo-topic --from-beginning --timeout-ms 8000 --max-messages 1
Wed Apr 15 18:19:48 UTC 2020
Processed a total of 1 messages
root@kafka-client:/# 

如您所见，我能够从外部访问 kafka.

As you can see, I was able to access the kafka from outside.

• 如果您还需要对 Zookeeper 进行外部访问，我会为您留下一个服务模型:

zookeeper-external-0.yaml

apiVersion: v1
kind: Service
metadata:
  labels:
    app: cp-zookeeper
    pod: demo-cp-zookeeper-0
  name: demo-cp-zookeeper-0-nodeport
  namespace: default
spec:
  externalTrafficPolicy: Cluster
  ports:
  - name: external-broker
    nodePort: 31181
    port: 12181
    protocol: TCP
    targetPort: 31181
  selector:
    app: cp-zookeeper
    statefulset.kubernetes.io/pod-name: demo-cp-zookeeper-0
  sessionAffinity: None
  type: NodePort

• 它将为其创建一个服务:

NAME                           TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)             AGE
demo-cp-zookeeper-0-nodeport   NodePort    10.0.5.67     <none>        12181:31181/TCP     2s

• 修补您的配置映射:

data:
  "31090": default/demo-cp-kafka-0-nodeport:31090
  "31181": default/demo-cp-zookeeper-0-nodeport:31181

• 添加入口规则:

        ports:
        - containerPort: 31181
          hostPort: 31181
          protocol: TCP

• 使用您的外部 IP 对其进行测试:

pod/zookeeper-client created
user@minikube:~$ kubectl exec -it zookeeper-client -- /bin/bash
root@zookeeper-client:/# zookeeper-shell 35.226.189.123:31181
Connecting to 35.226.189.123:31181
Welcome to ZooKeeper!
JLine support is disabled

如果您有任何疑问，请在评论中告诉我！

If you have any doubts, let me know in the comments!

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