feat(migration): complete WordPress migration and UX refinements

- Migrate historical posts, localized assets, and 103 comments - Colocate media into posts/<slug>/images/ and remove wp-content - Add native bilingual support for ai-can-change post (English default, /zh variant) - Support clean taxonomy routing (/category/:category and /tag/:tag) - Dynamically populate categories and tags in sitemap.xml - Fix header scroll padding/margin offsets for anchor and reference links - Constrain image and media widths to prevent content overflow - Redesign homepage recent posts to 4 compact editorial cards - Restore valid binary favicon.ico and high-res icon assets - Remove placeholder content and sample test comments
2026-09-16 23:09:09 -07:00
parent 8c0b04db0e
commit f52b3fe9e4
87 changed files with 3417 additions and 190 deletions
@@ -0,0 +1,32 @@
+---
+title: "Practical debugging methods for Kubelet"
+date: 2024-04-10
+author: "Pengzhan Hao"
+category: "Tech"
+tags: ["Debug","Kubelet","Kubernetes"]
+cover: "/posts-assets/debug-kubelet/images/cover.webp"
+excerpt: "Kubelet, a vital component in Kubernetes, runs on each node in your cluster. It acts as the field manager, receiving instructions from the Kubernetes API server and ensuring contai..."
+---
+Kubelet, a vital component in Kubernetes, runs on each node in your cluster. It acts as the field manager, receiving instructions from the Kubernetes API server and ensuring containerized applications run smoothly. Kubelet is responsible for downloading container images, pulling secrets, and launching pods – the basic units containing your application containers. It also monitors container health, restarts failed ones and reports their status back to the API server.
+
+Due to its central role, debugging Kubelet becomes crucial when troubleshooting your Kubernetes environment. In the post, we will continually expand methods on how to debug Kubelet, especially some practices on some real-world use cases.
+
+## Debug logs
+
+Like all others program's debugging, the most straightforward way for newbies and the easiest way for advanced developer is relying on logs. Similar to debugging Kubelet, bumping up verbosity to show more logs is the most intuitive approach when facing an issue. Like most components in Kubernetes, `kubelet` uses `klog` for logging and there are 10 verbosity levels(0-9).
+
+TL;DR: Bumping up to level 5 would satisfy most debugging needs.
+
+LevelMeaningExample0Always on (Warning, Error, Fatal)[Example](https://github.com/kubernetes/kubernetes/blob/d9c54f69d4bb7ae1bb655e1a2a50297d615025b5/pkg/kubelet/kubelet.go#L757-L757)1Default level logs when don't want any verbosity[Example](https://github.com/kubernetes/kubernetes/blob/d9c54f69d4bb7ae1bb655e1a2a50297d615025b5/pkg/kubelet/kubelet.go#L2527)2Most important logs when major operations happen, also the default verbosity level[Example](https://github.com/kubernetes/kubernetes/blob/d9c54f69d4bb7ae1bb655e1a2a50297d615025b5/pkg/kubelet/kubelet.go#L483-L483)3Extended information[Example](https://github.com/kubernetes/kubernetes/blob/d9c54f69d4bb7ae1bb655e1a2a50297d615025b5/pkg/kubelet/kubelet.go#L2176)4Debug level[Example](https://github.com/kubernetes/kubernetes/blob/d9c54f69d4bb7ae1bb655e1a2a50297d615025b5/pkg/kubelet/kubelet.go#L1731)5Trace level[Example](https://github.com/kubernetes/kubernetes/blob/d9c54f69d4bb7ae1bb655e1a2a50297d615025b5/pkg/kubelet/kubelet.go#L2821-L2821)6Display requested resources[Example](https://github.com/kubernetes/kubernetes/blob/d9c54f69d4bb7ae1bb655e1a2a50297d615025b5/pkg/kubelet/cm/cgroup_manager_linux.go#L401)7Display HTTP request headers[Example](https://github.com/kubernetes/kubernetes/blob/d9c54f69d4bb7ae1bb655e1a2a50297d615025b5/pkg/kubelet/logs/container_log_manager.go#L299)8Display HTTP request payload[Example](https://github.com/kubernetes/kubernetes/blob/d9c54f69d4bb7ae1bb655e1a2a50297d615025b5/pkg/kubelet/prober/prober_manager.go#L192)
+
+By the time, this note was written. In `kubelet` related code, level 8 was only used `pkg/kubelet/prober/prober_manager.go` and level 7 was only used in `pkg/kubelet/logs/container_log_manager.go`. 11 occurrences in level 6 were used, and all of them are not part of workload lifecycle related.
+
+## Add trace cide
+
+## Kubelet with Bpfcc-tools
+
+## Debugger
+
+## Further readings
+
+[Inotify watcher leaks in Kubelet](/posts/inotify-watcher-leaks-in-kubelet.html)