Specifying an external Load Balancing strategy in a YAML file

General Discussions
1

I’ve been reading about different strategies for the external load balancer in Kubernetes which include Round Robin, Kube-proxy L4 Round Robin Load Balancing, L7 Round Robin Load Balancing etc. but I cannot find anywhere where I would configure an externally exposed load balanced service to use a particular strategy type. I have created the following service description YAML file

apiVersion: v1
kind: Service
metadata:
name: epcluster-service
spec:
selector:
app: epcluster
ports:
- port: 8765
targetPort: 5000
type: LoadBalancer

This will create a service with a default Load Balancer. I cannot see how I would specify a strategy type e.g. Round Robin. I have extensively searched the web for this and although I can find many articles discussiong the strategies available, nowhere can I find how to acually choose one within a YAML file or via kurbctl.

Does anyone know how to do this, or am I misunderstanding how the Load Balancer is implemented?

Many thanks,

Damien

2

LoadBalancer services exist ‘outside’ of Kubernetes. They are part of the platform you’re on. GKE, AWS, or MetalLB are all different and have different sets of capabilities. There isn’t a way to really ‘normalize’ them from the Kubernetes perspective. They just have to satisfy the condition of directing external traffic to the hosts/pods.

For what you’re looking for, that either needs to be configured externally to Kubernetes OR some LB implementations can look at the annotations on a service for their provider specific configs.

Eg. LoadBalancer Service concepts  |  Google Kubernetes Engine (GKE)  |  Google Cloud

For your case, you should look at what LB specific configs your provider supports.

3

Thanks for your clear and detailed response. I had a feeling that this might be the case. I am currently using the limited Kubernetes instance that is available under Docker Desktop for testing. I suspect this also only offers a very limited range of LoadBalancing strategies. No probs, I’m just getting my head around how the system works and how to configure and depoy it in a production environment.

Thanks again,

Damien