WIP: Application load balancer controller by fischerman · Pull Request #3 · stackitcloud/application-load-balancer-controller

fischerman · 2026-06-24T20:24:10Z

How to categorize this PR?

/kind enhancement

What this PR does / why we need it:

Implements the first alpha version of the STACKIT ALB controller.

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Breaking changes:

nschad · 2026-06-25T09:58:47Z

@fischerman either mark the PR as "Draft" or use "WIP" as the title. The PR will then automatically marked as WIP/Draft

ske-prow · 2026-06-25T14:33:32Z

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dergeberl

This is my first batch of review comments. Only had a look into the /cmd/*, /pkg/controller/* (except the tests) and the *.md files, yet. I will continue with my review for the rest.

Maybe some comments are already resolved as you also pushed during my review (I did not crosscheck again, before submitting the comments now).

dergeberl · 2026-06-26T12:04:57Z

+### Limits
+
+The following limitations are imposed directly by the STACKIT ALB API (not the controller itself):
+- Maximum targets per pool: An individual target pool can contain a maximum of 250 targets.


The limit should be 1000 or?

Limit is still 250. SKE will look into limiting the auto scaler to 250 for clusters the have the ALB extension enabled.

dergeberl

Comments for the stackit package and testutil

dergeberl · 2026-06-29T11:23:01Z

+					CertificateIds: []string{},
+				},
+			}
+			for fingerprint, cert := range t.certificates {


Map interactions are not deterministic. If I remember correctly the order in the ALB matters, as always the first match will be used. This could lead in a flapping which cert is used if multiple are fitting.

Fixed in 5c25864

The order is stable but cannot be influenced by the customer.

TODO: Document behavior when two certificates collide.

dergeberl · 2026-06-29T13:48:03Z

@@ -0,0 +1,302 @@
+package ingress


In the update.go are multiple functions which also should be tested, like getServicesForIngresses, getTLSSecretsFromIngresses, getCertificatesForIngressClass. But also the logic for duplicateCerts should get tested.

dergeberl · 2026-06-29T14:58:46Z

@@ -0,0 +1,658 @@
+package spec


We should also add tests for:

~~the AnnotationHTTPSOnly and that it not serves HTTP.~~

~~the sorting based on AnnotationPriority and creation timestamp.~~

AnnotationPlanID

the handling when setting not allowed values in annotation (like no valid int/port, not valid cidr in source range)

~~GetUnusedCertificates~~

Added tests for 1, 2 and 5 in c9d5229

Updated comment

dergeberl · 2026-06-30T05:48:57Z

@@ -0,0 +1,85 @@
+apiVersion: apps/v1


We should align this with the deploy of CSI and CCM in cloud-provider-stackit (which are also not perfect, see stackitcloud/cloud-provider-stackit#1162).
For example:

we can use also the kube-system namespace as this is also a system component like CSI and CCM

the cloud config don't need to be a secret

the mount path of the service account and cloud config

the apiEndpoints don't need to be in the example (this is only internally needed)

lets also create a /deploy folder instead if the /samples/deploy/

we need to find a image tag which is working and don't need to be updated like latest (not sure if this will be tagged on release)

With #6 we get a latest tag for tagged versions. Lets use that in the deployment.

Done in 5248047

I vote for latest tag here. We can leave it like it is for now and solve this directly before merging. After merge I will create a release which then also creates the latest tag

Will keep the thread unresolved as a reminder.

Append ingress class name to ALB name

Log event when ALB cannot be reconciled due to invalid configuration (it will not be requeued) Use the already retrieved, created or updated LB to update the status of the ingresses. Don't update the status on invalid configurations.

ske-prow Bot added do-not-merge/needs-kind Indicates a PR lacks a `kind/foo` label and requires one. size/XXL Denotes a PR that changes 1000+ lines, ignoring generated files. labels Jun 24, 2026

nschad changed the title ~~Draft: Application load balancer controller~~ WIP: Application load balancer controller Jun 25, 2026

ske-prow Bot added the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label Jun 25, 2026

nschad force-pushed the main branch from e5c3fee to fba4e1b Compare June 25, 2026 14:11

dergeberl requested review from breuerfelix, dergeberl and hown3d June 25, 2026 14:29

ske-prow Bot added the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Jun 25, 2026

fischerman force-pushed the albc branch from d73714b to 209f335 Compare June 25, 2026 14:37

ske-prow Bot removed the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Jun 25, 2026

fischerman commented Jun 26, 2026

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Comment thread .golangci.yaml

Adi146 reviewed Jun 26, 2026

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Comment thread pkg/controller/ingress/setup.go Outdated

dergeberl reviewed Jun 26, 2026

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dergeberl reviewed Jun 29, 2026

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hown3d reviewed Jun 29, 2026

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fischerman mentioned this pull request Jun 29, 2026

WIP: Add Application Load Balancer Controller Manager stackitcloud/cloud-provider-stackit#879

Closed

dergeberl reviewed Jun 29, 2026

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Comment thread pkg/controller/ingress/update.go Outdated

Comment thread pkg/controller/ingress/update.go Outdated

Comment thread pkg/controller/ingress/update.go Outdated

Comment thread pkg/controller/ingress/ingressclass_controller.go

dergeberl reviewed Jun 29, 2026

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Comment thread pkg/controller/ingress/suite_test.go

dergeberl reviewed Jun 29, 2026

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dergeberl reviewed Jun 30, 2026

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Comment thread pkg/controller/ingress/ingressclass_controller.go Outdated

dergeberl reviewed Jun 30, 2026

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Comment thread pkg/controller/ingress/spec/worktree.go

dergeberl reviewed Jun 30, 2026

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Comment thread pkg/controller/ingress/spec/worktree.go

ftl reviewed Jun 30, 2026

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Comment thread cmd/application-load-balancer-controller/main.go

ftl reviewed Jun 30, 2026

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Comment thread cmd/application-load-balancer-controller/main.go

dergeberl reviewed Jun 30, 2026

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Comment thread hack/tools.mk Outdated

fischerman added 13 commits July 7, 2026 16:20

Fix linter issues

4e64691

Remove unused methods from ALB API

b610728

Support paging for list endpoint

80483a4

Move values into constants

5db59af

Added tests for the status of ingresses

5468f37

Extend change detection and tests

7bea972

Fix linter issues

630ddf4

Refactor update.go

81d358c

Updated ALB SDK to latest

a90ab33

Add tests for out of range HTTP/S ports

9008b15

Paraphrase limits

d4ea623

Remove sanitize label function

60459aa

Added controller tests for node changes

a578e28

fischerman commented Jul 10, 2026

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Comment thread docs/user.md

dergeberl reviewed Jul 10, 2026

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Comment thread pkg/stackit/applicationloadbalancercertificates.go

dergeberl reviewed Jul 10, 2026

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Comment thread pkg/controller/ingress/diff/diff.go Outdated

dergeberl reviewed Jul 10, 2026

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Comment thread pkg/controller/ingress/spec/worktree.go

fischerman added 9 commits July 10, 2026 15:49

Log event while waiting for load balancer to become ready

0e9f09a

Append ingress class name to ALB name

Refactor tests for certificate changes

b5a40a3

Fix linter issues

74aa536

Add page limit for listing certificates

cfe62b2

Refactor HTTPS option diff

076a909

Refactor isNodeTerminating with helper functions

be55146

Add troubleshooting section

a508db2

Run go mod tidy

eb25ad3

dergeberl mentioned this pull request Jul 13, 2026

Add application load balancer controller with ingress support stackitcloud/gardener-extension-provider-stackit#54

Open

fischerman added 3 commits July 13, 2026 16:20

Parse service plan IDs

bd45919

Fixed linter issues

3ef46b1

Add validation for source ranges

4667166

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fischerman commented Jun 24, 2026 •

edited by nschad

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dergeberl Jun 29, 2026 •

edited

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