How to set the ring-balancer to use latency algorithm?

[stricklandye]

I want to set ring-balancer to use latency algorithm , following the docs here I create a KongIngress resource but I go error message likes:

Unsupported value: "latency": supported values: "round-robin", "consistent-hashing", "least-connection

The deploy file seems that latency algorithm is not added in to CRD. So how should I use latency algorithm? Here are the algorithms available by default,quoted from previous mentioned deploy file.

    algorithm:
      description: Algorithm is the load balancing algorithm to use.
      enum:
      - round-robin
      - consistent-hashing
      - least-connections

[pmalek]

Hi @stricklandye 👋

It seems that the latency option was only added in Gateway 3.2: https://github.com/Kong/kong/blob/master/CHANGELOG.md#320

• Add a new load-balancing algorithm option latency to the Upstream entity. This algorithm will choose a target based on the response latency of each target from prior requests. feat(balancer): add latency balancer algorithm kong#9787

I suppose you're running an older version then 3.2 hence the reason for this.

[stricklandye]

Thanks for your response. I use kong 3.3 with kic 2.11 actually. Steps to reproduce:
KongIngress:

# kong_lb_latency.yaml 
apiVersion: configuration.konghq.com/v1
kind: KongIngress
metadata:
  name: kong-lb-latency
upstream:
  algorithm: latency

$kubectl describe pod kong-1691733995-kong-759f4484d-562zx -n kong  | grep Image
    Image:         kong:3.3
    Image ID:      docker-pullable://kong@sha256:88aad0fa3c603af1b2ced86f33f0c28f664bf7b53c92aec1256746136b8832ca
    Image:          kong/kubernetes-ingress-controller:2.11
    Image ID:       docker-pullable://kong/kubernetes-ingress-controller@sha256:ea24cfa6d2251aaaf050a245420259dc4e58314cf6fbeedb463cff2fe65becb7
    Image:          kong:3.3
    Image ID:       docker-pullable://kong@sha256:88aad0fa3c603af1b2ced86f33f0c28f664bf7b53c92aec1256746136b8832ca
$ k apply -f kong_lb_latency.yaml
The KongIngress "kong-lb-latency" is invalid: upstream.algorithm: Unsupported value: "latency": supported values: "round-robin", "consistent-hashing", "least-connections"

And, I think it's irrelevant to kong version, because the follwing properties in deploy file does not include the latency algorithm. So the right way is to append latency alogrithm to the manifest?

    properties:
      algorithm:
        description: Algorithm is the load balancing algorithm to use.
        enum:
        - round-robin
        - consistent-hashing
        - least-connections
        type: string

[pmalek]

Oh yes, that's correct we don't allow it via the enum

kubernetes-ingress-controller/pkg/apis/configuration/v1/kongingress_types.go

Line 165 in 57daa5d

// +kubebuilder:validation:Enum=round-robin;consistent-hashing;least-connections

.

I've created #4616 to track the inclusion of this algorithm.

[stricklandye]

Glad to see it. At first I thought it was because latency algorithm had some bugs so it couldn't be used in KIC :D.

[pmalek]

@stricklandye this was merged in #4703 and should land in 2.12.

[stricklandye]

Nice. Thanks for your cooperation. :D