We have created a custom Docker image that can route UDP traffic in a Kubernetes cluster (Amazon EKS). The Docker image includes a Helm chart that can be used to deploy a UDP application to a Kubernetes cluster.
The UDP listener service listens on the specified UDP port and outputs to the container log. The Helm chart packages and deploys the application to Elastic Kubernetes Service (EKS)
Git Repository with Docker Image and Helm chart
Link – https://github.com/dev-coderise/udp-listener
cd deploy/udp-listener
helm upgrade --install udp-listener .
helm uninstall udp-listener
By default, you can run it like this
docker run -p 0.0.0.0:5005:5005 -p 0.0.0.0:5005:5005/udp --name udp-listener coderiseio/udp-listener
Run UDP listener on a different port
You can make it listen on another port
docker run -p 0.0.0.0:4444:4444 -p 0.0.0.0:4444:4444/udp -e UDPPORT=4444 --name udp-listener coderiseio/udp-listener
Assign Static IP to Load Balancer
We provisioned a service with LoadBalancer type which allows to route UDP traffic in Kubernetes. Optionally, a static IP can be assigned to the Load Balancer. This way the DNS always maps to the same IP. You can create a Elastic IP in AWS and then assign it using service annotations in the values.yaml ( LINK ). If this is not required, you can comment out these lines in values.yaml.
service.beta.kubernetes.io/aws-load-balancer-eip-allocations: eipalloc-057553b2156ec2c74service.beta.kubernetes.io/aws-load-balancer-subnets: coderise_test_vpc_ca-Public1service.beta.kubernetes.io/aws-load-balancer-security-groups: sg-0913f81f52beb4f4a
Testing to ensure we can route UDP Traffic in Kubernetes
Use some tool like PacketSender or in another terminal:
#localhost
nc -u localhost 5005
And start sending data. You should see your text reflected in the docker run terminal
udp:
container_name: my-udp-listener
image: coderiseio/udp-listener
environment:
- UDPPORT=4001
ports:
- "0.0.0.0:4001:4001"
- "0.0.0.0:4001:4001/udp"
View UDP listener service logs
View its logs:
docker logs <udp-listener-pod>
Conclusion
In this blog, we discussed how to route UDP traffic in Kubernetes. We also covered how to use the Docker image and Helm charts to install the UDP listener service in a Kubernetes cluster. Finally, we looked at how to assign a static IP to the load balancer provisioned by the UDP listener service.
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