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Haowei Cai

PROFILE

Haowei Cai

Haowei Chen developed and stabilized Pressure Stall Information (PSI) observability features across the Kubernetes stack, focusing on resource contention visibility and proactive capacity planning. Working in the kubernetes/kubernetes and kubernetes/enhancements repositories, Haowei designed and implemented API surfaces, feature gates, and end-to-end monitoring for PSI metrics using Go, Kubernetes, and Protobuf. He advanced PSI-based node conditions through phased rollouts and robust documentation, aligning with Kubernetes release cycles. Haowei also improved test reliability by refining CPU stress tests and enhancing test infrastructure, reducing CI flakiness. His work demonstrated depth in backend development, system monitoring, and technical writing within large-scale cloud environments.

Overall Statistics

Feature vs Bugs

80%Features

Repository Contributions

19Total
Bugs
1
Commits
19
Features
4
Lines of code
4,048
Activity Months4

Work History

August 2025

1 Commits

Aug 1, 2025

In August 2025, focused on stabilizing the Kubernetes test suite by delivering a CPU stress test reliability improvement. Implemented a 500m CPU limit for the cpu-stress-pod, ensuring deterministic CPU pressure during tests, reducing flaky CI failures, and accelerating feedback loops. Change was committed to kubernetes/kubernetes (ea9d7ff8656db94393d16645fdc10402b969e99c).

July 2025

3 Commits • 2 Features

Jul 1, 2025

July 2025 monthly summary: Delivered PSI-related features in the kubernetes/kubernetes repo focused on observability and reliability of node resource pressure metrics. Major bugs fixed: none reported this month. Overall impact: promoted Kubelet PSI metrics exposure to beta in Kubernetes 1.34, expanded end-to-end testing for CPU/Memory/I/O pressure, and strengthened test infrastructure with feature flags and cgroup v2 compatibility checks. Technologies/skills demonstrated include Go, Kubernetes feature gates, end-to-end testing, and handling of cgroup v2 awareness.

June 2025

8 Commits • 1 Features

Jun 1, 2025

June 2025 monthly summary focusing on delivering the PSI-based Node Conditions and Metrics rollout (KEP-4205) in kubernetes/enhancements. Central achievements included advancing Phase 2 readiness, establishing governance for PSI-based node conditions, and aligning KEP updates with Beta requirements and 1.34 timelines. The work created a clear phased rollout path with phase separation and robust documentation to reduce rollout risk and enable cross-team coordination. Minor documentation fixes and clarifications improved maintainability and reviewer efficiency, while monitoring and version-skew details were refined to support safe upgrades and observability.

March 2025

7 Commits • 1 Features

Mar 1, 2025

March 2025: Delivered cross-stack PSI observability across Kubernetes (Kubelet, CRI, and monitoring) to improve resource contention visibility. Implemented alpha Kubelet PSI feature gate, API surface for PSI metrics, exposure of PSI metrics from cadvisor to the summary API and Prometheus, CRI API extension for PSI, and CRI stats provider integration, reinforced by unit and end-to-end tests. This enables end-to-end PSI monitoring for nodes, pods, containers, and sandboxes, driving proactive capacity planning, faster troubleshooting, and data-driven scheduling decisions.

Activity

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Quality Metrics

Correctness89.4%
Maintainability85.4%
Architecture89.4%
Performance79.0%
AI Usage21.0%

Skills & Technologies

Programming Languages

GoMarkdownYAMLgomarkdownprotobufyaml

Technical Skills

API DevelopmentAPI designAPI developmentCloud ComputingContainerizationDocumentationFeature Gate ImplementationFeature Gate ManagementGoGo programmingKEPKEP ManagementKubernetesMetricsMonitoring

Repositories Contributed To

2 repos

Overview of all repositories you've contributed to across your timeline

kubernetes/kubernetes

Mar 2025 Aug 2025
3 Months active

Languages Used

Goprotobuf

Technical Skills

API DevelopmentAPI designAPI developmentCloud ComputingContainerizationFeature Gate Implementation

kubernetes/enhancements

Jun 2025 Jun 2025
1 Month active

Languages Used

MarkdownYAMLgomarkdownyaml

Technical Skills

DocumentationKEPKEP ManagementKubernetesMetricsSystem Design

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