This guide walks through checking the current kernel, adding the ELRepo repository, listing available kernels, installing the latest long‑term 5.4 kernel on CentOS 7, setting it as default, removing old kernels, and verifying the upgrade after reboot.
The article analyzes write latency caused by a slab lock in the monitoring agent, evaluates kernel upgrades and BIOS power‑saving settings, and explains CPU power‑state mechanisms (P‑States, C‑States, T‑States) with performance testing scripts to guide server performance tuning.
The article recounts a half‑year investigation of a high‑performance proxy cluster whose Docker hosts repeatedly crashed due to kernel null‑pointer dereferences, detailing log analysis, three faulty hypotheses, extensive web research, kernel and Docker upgrades, and the final operational lessons learned.
After a painful P1 incident caused by a kernel upgrade, this article outlines how to properly reboot a Linux server by documenting pre‑restart state, verifying post‑restart consistency with process and port snapshots, and using simple commands such as ps, netstat, diff, and last to ensure service continuity.
