Add Keda Deployer #3386

creydr · 2026-01-22T13:22:40Z

Changes

🎁 Add the possibility to deploy a function with a Keda HTTP scaler

Currently only exposes the function cluster internally. Issue to make the externally available is #3391.

/kind enhancement

Flow

flowchart TD
    U(User/other service) -->|accesses| A
    A[Entrypoint - Bridge Service] -->|forwards request| B
    B[Keda HTTP add-on interceptor-proxy] -->|forwards request| C
    B -.->|reads| E
    B -.->|scales| D
    C[App service] -->|forwards request| D
    D[Deployment]
    E{HTTPScaledObject}

Test procedure:

Build the func-cli with those changes
make build
Clone a repo with a function
e.g. cd /tmp & git clone https://github.com/creydr/func-go-hello-world

Make sure you have Keda with the HTTP-add-on installed

kubectl apply --server-side -f https://github.com/kedacore/keda/releases/download/v2.17.0/keda-2.17.0.yaml
kubectl apply --server-side -f https://github.com/kedacore/keda/releases/download/v2.17.0/keda-2.17.0-core.yaml


kubectl apply --server-side -f https://github.com/kedacore/http-add-on/releases/download/v0.11.1/keda-add-ons-http-0.11.1-crds.yaml
kubectl apply --server-side -f https://github.com/kedacore/http-add-on/releases/download/v0.11.1/keda-add-ons-http-0.11.1.yaml

Deploy the function with the keda deployer:

<path to built-func-binary> deploy --registry <your registry> --deployer keda
Building function image
Still building
Still building
Yes, still building
🙌 Function built: quay.io/creydr/func-go-hello-world/func-go-hello-world:latest
Pushing function image to the registry "quay.io" using the "creydr" user credentials
✅ Function deployed in namespace "default" and exposed at URL: 
   http://func-go-hello-world-interceptor-bridge.default.svc:8080

Check for the created resources:

kubectl get httpscaledobject                            
NAME                  TARGETWORKLOAD                           TARGETSERVICE            MINREPLICAS   MAXREPLICAS   AGE     ACTIVE
func-go-hello-world   apps/v1/Deployment/func-go-hello-world   func-go-hello-world:80   0             10            2m48s   True

kubectl get svc
NAME                                    TYPE           CLUSTER-IP     EXTERNAL-IP                                                  PORT(S)    AGE
func-go-hello-world                     ClusterIP      10.96.245.62   <none>                                                       80/TCP     3m48s
func-go-hello-world-interceptor-bridge   ExternalName   <none>         keda-add-ons-http-interceptor-proxy.keda.svc.cluster.local   8080/TCP   3m41s

Start a load test and see the pods getting scaled by Keda:

cat <<-EOF | kubectl apply -f  -                                        
apiVersion: batch/v1              
kind: Job     
metadata:
  name: hey-load-test
spec:    
  template:                                                     
    spec:  
      containers:                           
      - name: hey 
        image: quay.io/creydr/hey:latest
        args:
          - "-n"     
          - "1000000"
          - "-c"
          - "100"
          - "http://func-go-hello-world-interceptor-bridge:8080"
      restartPolicy: Never
  backoffLimit: 1
EOF

kubectl get po
NAME                                   READY   STATUS    RESTARTS   AGE
func-go-hello-world-6b895b8b59-8x2wz   1/1     Running   0          58s
func-go-hello-world-6b895b8b59-bhgzd   1/1     Running   0          43s
func-go-hello-world-6b895b8b59-dg4q9   1/1     Running   0          58s
func-go-hello-world-6b895b8b59-dgp92   1/1     Running   0          43s
func-go-hello-world-6b895b8b59-h8pzh   1/1     Running   0          27s
func-go-hello-world-6b895b8b59-j6zwd   1/1     Running   0          43s
func-go-hello-world-6b895b8b59-k5rkd   1/1     Running   0          63s
func-go-hello-world-6b895b8b59-n4582   1/1     Running   0          43s
func-go-hello-world-6b895b8b59-rh56x   1/1     Running   0          27s
func-go-hello-world-6b895b8b59-vfxtj   1/1     Running   0          58s
hey-load-test-t4mwp                    1/1     Running   0          68s

Release Note

Add keda deployer

knative-prow · 2026-01-22T13:22:47Z

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: creydr
Once this PR has been reviewed and has the lgtm label, please assign dprotaso for approval. For more information see the Code Review Process.

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codecov · 2026-01-22T14:13:44Z

Codecov Report

❌ Patch coverage is 49.13043% with 234 lines in your changes missing coverage. Please review.
✅ Project coverage is 53.67%. Comparing base (f8dd264) to head (f3f5b87).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/keda/deployer.go	58.01%	73 Missing and 16 partials ⚠️
pkg/deployer/testing/integration_test_helper.go	0.00%	38 Missing ⚠️
pkg/keda/describer.go	50.00%	28 Missing and 8 partials ⚠️
pkg/keda/lister.go	56.89%	19 Missing and 6 partials ⚠️
pkg/keda/remover.go	32.43%	20 Missing and 5 partials ⚠️
cmd/client.go	30.00%	7 Missing ⚠️
pkg/keda/wait.go	63.63%	3 Missing and 1 partial ⚠️
cmd/deploy.go	66.66%	3 Missing ⚠️
pkg/k8s/deployer.go	50.00%	2 Missing and 1 partial ⚠️
pkg/keda/client.go	50.00%	2 Missing and 1 partial ⚠️
... and 1 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3386      +/-   ##
==========================================
- Coverage   54.74%   53.67%   -1.08%     
==========================================
  Files         173      179       +6     
  Lines       20112    20147      +35     
==========================================
- Hits        11011    10814     -197     
- Misses       7992     8210     +218     
- Partials     1109     1123      +14

Flag	Coverage Δ
e2e	`37.23% <8.13%> (+14.27%)`	⬆️
e2e go	`?`
e2e node	`?`
e2e python	`?`
e2e quarkus	`?`
e2e rust	`?`
e2e springboot	`?`
e2e typescript	`?`
integration	`17.58% <60.56%> (-1.07%)`	⬇️
unit macos-14	`42.35% <2.53%> (-2.34%)`	⬇️
unit macos-latest	`42.35% <2.53%> (-2.34%)`	⬇️
unit ubuntu-24.04-arm	`42.66% <1.95%> (-2.16%)`	⬇️
unit ubuntu-latest	`43.24% <2.53%> (-2.33%)`	⬇️
unit windows-latest	`42.37% <2.53%> (-2.34%)`	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

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gauron99 · 2026-01-22T15:13:56Z

/test all

creydr · 2026-01-23T11:28:48Z

pkg/keda/deployer.go

+			CooldownPeriod: ptr.To(int32(300)),
+			ScalingMetric: &httpv1alpha1.ScalingMetricSpec{
+				Rate: &httpv1alpha1.RateMetricSpec{
+					TargetValue: 100,
+					Window: metav1.Duration{
+						Duration: time.Minute,
+					},
+					Granularity: metav1.Duration{
+						Duration: time.Second,
+					},
+				},
+			},


@linkvt do you have any recommendations for those metrics? I mostly took them from the example 🙃

creydr · 2026-01-23T11:54:51Z

/cc @gauron99 @lkingland @matejvasek

knative-prow-robot · 2026-01-23T15:19:27Z

PR needs rebase.

Details

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linkvt · 2026-01-24T19:30:26Z

go.mod


+// Override invalid k8s.io/client-go v1.5.2 requirement from keda http-add-on
+// keda uses a replace directive internally, but those don't propagate to dependents
+replace k8s.io/client-go => k8s.io/client-go v0.34.3


PR to resolve this in the KHA is open and will probably be released next week, just need to fix CI, see kedacore/http-add-on#1424

knative-prow bot added do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. kind/enhancement labels Jan 22, 2026

knative-prow bot requested review from dsimansk and jrangelramos January 22, 2026 13:22

knative-prow bot added the size/XXL Denotes a PR that changes 1000+ lines, ignoring generated files. label Jan 22, 2026

creydr force-pushed the keda-deployer branch from 2d7459c to 989fbf8 Compare January 22, 2026 14:01

knative-prow-robot added the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Jan 22, 2026

creydr added 3 commits January 22, 2026 15:26

Add Keda Deployer

b3937bc

Run hack/update-codegen.sh

e0fcca9

Fix linter issues

a12ae90

creydr force-pushed the keda-deployer branch from 989fbf8 to a12ae90 Compare January 22, 2026 14:26

knative-prow-robot removed the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Jan 22, 2026

creydr added 7 commits January 22, 2026 17:41

Scale down keda-http-add-on to only one replica in CI to save resources

2896fff

Allow to specify the cluster-domain

8206b24

Remove outdated comment

5fceb4d

Update comment

9b8b61a

Remove port section in external name service

d4dc779

Rename interceptor-proxy service to interceptor-bridge service

d9a04ee

Fix: add owner reference in bridge service too

ea2966e

creydr force-pushed the keda-deployer branch from 15a82c0 to ea2966e Compare January 23, 2026 11:07

Run make schema-generate

f3f5b87

creydr changed the title ~~[WIP] Add Keda Deployer~~ Add Keda Deployer Jan 23, 2026

knative-prow bot removed the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label Jan 23, 2026

creydr commented Jan 23, 2026

View reviewed changes

knative-prow bot requested review from gauron99 and lkingland January 23, 2026 11:54

knative-prow bot requested a review from matejvasek January 23, 2026 11:54

knative-prow-robot added the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Jan 23, 2026

linkvt reviewed Jan 24, 2026

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Flow

Test procedure:

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