In our Openshift ecosystem, we have a kafka instance sourced from wurstmeister/kafka. As of now I am able to have the kafka accessible withing the Openshift system using the below parameters,
KAFKA_LISTENERS=PLAINTEXT://:9092
KAFKA_ADVERTISED_HOST_NAME=kafka_service_name
And ofcourse, the params for port and zookeper is there.
I am able to access the kafka from the pods within the openshift system. But I am unable to access kafka service from the host machine. Eventhough I am able to access the kafka pod using its IP and able to telnet the pod using, telnet Pod_IP 9092
When I am trying to connect using the kafka producer from the host machine, I am getting the below error,
2017-08-07 07:45:13,925] WARN Error while fetching metadata with
correlation id 2 : {tls21=LEADER_NOT_AVAILABLE}
(org.apache.kafka.clients.NetworkClient)
And When I try to connect from Kafka consumer from the host machine using IP, it is blank.
Note: As of now, its a single openshift server. And the use case is for dev testing.
Maybe you want to take a look at this POC for having Kafka on OpenShift ?
https://github.com/EnMasseProject/barnabas
Related
I am building a SvelteKit application with Kafka Support. I have created a kafka.js file and tested the kafka support with a local kafka setup, which is successful. Now, When I replaced the topic name with a topic that is running in the kafka of our Kubernetes cluster, am not seeing any response.
How do I test this connection that is establishing between Kafka in Kubernetes cluster and the JS web application ? Any hints could be much helpful. Doing just console logs are not helpful so far because kafka itself not getting hit.
Any two pods deployed in the same namespace can communicate using local service names. So, do the brokers have a Service resource?
For example, assuming you are in namespace: default, and you have kafka-svc, then you'd setup bootstrap.servers: kafka-svc.svc.cluster.local.
You also need to configure Kafka's advertised.listeners. Related blog - https://strimzi.io/blog/2019/04/17/accessing-kafka-part-1/
But this requires NodeJS (or other language) backend, and not SvelteKit UI (which cannot connect to backend TCP server, only use some HTTP bridge). Your HTTP options would include some custom server, or Confluent REST Proxy, Strimzi Kafka Bridge, etc. But you were already told this.
I have used the Kafka cluster (with replication) click to deploy container from Google on kubernetes. How do I expose the brokers so I can consume from an external consumer? I'm very new to kunernetes.
I have tried exposing the broker nodes with a load balancer but the external ip given
I opened the port with a firewall rule
But when connecting from my consumer it throws an error about being disconnected
Any help would be great, I can provide more info if asked.
You cannot use a load balancer. Kafka clients must talk directly to the brokers.
Firewall is a good step, but you need to ensure each of the brokers are exposed properly via advertised.listeners within and outside of the VPC. Refer blog post.
Alternative, within GKE, you can run Strimzi Operator, which handles Kubernetes resources for you with regard to the Kafka cluster.
Able to connect successfully to local kafka broker/cluster running locally (dockerized) using Conduktor, but when trying to connect to Kafka cluster running on Unix VM, getting below error.
Error:
"The broker [...] is reachable but Kafka can't connect. Ensure you have access to the advertised listeners of the the brokers and the proper authorization"
Appreciate any assistance.
running locally (dockerized)
When running in docker, you need to ensure that the ports are accessible from outside of your container. To verify this, try doing a telnet <ip> <port> and check if you are able to connect.
Since the error message says, the broker is reachable, I suppose you would be able to successfully telnet to the broker.
Next, check your broker config called advertised.listeners. Here you need to mention your IP:Port combination where IP is what you will be giving in your client program i.e. Conduktor.
An example for that would be
advertised.listeners=PLAINTEXT://1.2.3.4:9092
and then restart your broker and reconnect. If you are using ssl then you need to provide some extra configuration. See Configuring Kafka brokers for more.
Try to add in /etc/hosts (Unix-like) or C:\Windows\System32\drivers\etc\hosts (windows-like) the Kafka server in such manner kafka_server_ip kafka_server_name_in_dns (e.g. 10.10.0.1 kafka).
I have a cluster inside a VPN which contains a server with private IP. I'm trying to set up a Kafka communication between an external server to my private server. My approach is to set an IP table where a public IP is pointing my private IP. Also, I opened the port 9092 and 9093 to make it reachable from outside. Now I am available to connect successfully to my server with the public IP from the external server.
telnet <public_ip> 9092
Connected to <public_ip>
My kafka broker is under a cloudera cluster and I created it with Cloudera Manager. The configuration is the following:
kafka.properties:
listeners=PLAINTEXT://<private_ip>:9092,SSL://<private_ip>:9093
advertised.listeners=PLAINTEXT://<private_ip>:9092,SSL://<private_ip>:9093
advertised.host.name:
<public_ip>
Using this broker configuration the comunication works perfectly inside the cluster either using the public_ip or private_ip of the kafka broker host.
What I see now is that I have a working broker that can be used with a public_ip and a external server that is able to reach the public_ip and it's required ports. But when I try to connect to the broker from a external server, I have the following error:
NO BROKERS AVAILABLE
There's no more information of the error. On my external server I have the kafka python package where I configure the producer as:
"bootstrap_servers": ["<publi_ip>:9092"]
on a existing TOPIC of my kafka broker.
Especifications:
private host
cloudera: CDH 5.12.0
kafka: kafka 2.2.0-1.2.2.0
zookeeper: Zookeeper 3.4.5
external host
kafka Python package: kafka-python==1.4.2
The problem is very similar to this post. But in this case he uses a forwarded port with public ip. Is any possibility to do it with ip tables? Anyone has managed to do it on a cloudera cluster?
Thank you in advance.
The question isn't specific to Cloudera or Python. And I don't think Cloudera Manager has some setting that'll set this up for you.
advertised.listeners will have to be a publicly resolvable address that can be used to access each broker individually by clients (e.g two brokers cannot have the same listener setting and be used from a port forward from the public address to the internal address)
Your setup is very similar to Kafka running in Docker or Cloud providers such as AWS, in that you're interacting over two networks, so refer to this blog for more information
Also, unless you setup some other firewall settings to prevent random access, don't expose brokers in the plaintext protocol
I'm not able to access kafka which is in remote server from my local server.
I tried to set parameter advertised.listeners=PLAINTEXT://ip:port in server.properties of kafka where ip is the public ip of my remote machine where kafka is. But still I'm not able to connect. What should I need to do next? I'm using confluent kafka of version 3.3.0.