fix(kubelet): remove streamingConnectionIdleTimeout for k8s >= 1.34

[abigailliang-aks-sig-node]

Summary

Remove streamingConnectionIdleTimeout from both the kubelet command line and the kubelet config file for Kubernetes >= 1.34, where this field was removed from KubeletConfiguration.

Context: RP-side flow (scriptless path)

Step 1: defaults_kubelet.go — removeKubeletFlags()
        └── k8s >= 1.34: delete(kubeletConfig, "--streaming-connection-idle-timeout")
                ↓
        kubeletConfig map (flag is already gone)
                ↓
Step 2: scriptless_direct.go — processKubeletConfigFileContent()
        └── cfg.StreamingConnectionIdleTimeout = kubeletFlags["--streaming-connection-idle-timeout"]
            → empty string (key was deleted in step 1)
                ↓
Step 3: scriptless_direct.go — processKubeletFlags()
        └── filterKubeletFlags() strips translated flags when enableKCF=true
            → flag not on command line either way
                ↓
Step 4: Proto sent to aks-node-controller
        └── KubeletConfigFileConfig.StreamingConnectionIdleTimeout = "" (omitted by protojson)

RP already handles this in removeKubeletFlags(). However, the field may still arrive in KubeletConfigFileConfig from:

• Older RP versions that haven't rolled out yet
• The GetAKSNodeConfig (NBC conversion) path where the removal may not be applied

Changes (defense-in-depth)

File	Change
aks-node-controller/helpers/utils.go	ValidateAndSetLinuxKubeletFlags(): delete --streaming-connection-idle-timeout for >= 1.34
aks-node-controller/parser/parser.go	getCSEEnv(): clear KubeletConfigFileConfig.StreamingConnectionIdleTimeout for >= 1.34 before marshaling
pkg/agent/baker.go	ValidateAndSetLinuxNodeBootstrappingConfiguration(): same flag deletion for the old NBC path

Why both flag deletion AND config file clearing?

• Flag deletion (helpers/utils.go, baker.go): covers enableKCF=false case where translated flags stay on the command line
• Config file clearing (parser.go): covers enableKCF=true case where the field would appear in kubeletconfig.json if RP sets it

Test plan

• unit tests
• local e2e tests

[Copilot]

Pull request overview

This PR aims to prevent streamingConnectionIdleTimeout from being propagated to kubelet for Kubernetes >= 1.34, where the corresponding KubeletConfiguration field/flag has been removed, by stripping it from kubelet CLI flags and clearing it from the kubelet config-file content.

Changes:

• Delete --streaming-connection-idle-timeout from kubelet flags for Kubernetes >= 1.34 in both the legacy NodeBootstrappingConfiguration path and the aks-node-controller helper path.
• Clear KubeletConfigFileConfig.StreamingConnectionIdleTimeout for Kubernetes >= 1.34 before marshaling kubelet config-file JSON in aks-node-controller.
• Add version gating comments explaining why the field must not appear for 1.34+.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
pkg/agent/baker.go	Removes --streaming-connection-idle-timeout from kubelet flags for k8s >= 1.34 in the NodeBootstrappingConfiguration validation path.
aks-node-controller/parser/parser.go	Clears StreamingConnectionIdleTimeout before kubelet config-file JSON marshaling for k8s >= 1.34.
aks-node-controller/helpers/utils.go	Removes --streaming-connection-idle-timeout from kubelet flags for k8s >= 1.34 in helper validation.

[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

[abigailliang-aks-sig-node]

this change block due to gofmt/goimports column alignment.

When a struct literal contains multiple fields, gofmt attempts to align the values ​​following the colons into the same column. The width of the aligned column is determined by the longest field name in the group:

[abigailliang-aks-sig-node]

same gofmt behave

[github-actions]

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Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Jul 3, 2026, 12:14 AM