A temporary test server on Tianyi Cloud was compromised by a malicious XMRig miner masquerading as fail2ban, causing CPU usage to skyrocket; the article details how the intrusion was discovered, the forensic steps taken, and a comprehensive remediation and hardening guide to prevent similar attacks.
After receiving an alarm that a production container’s CPU usage surged past 90%, I investigated the JVM metrics, discovered excessive young and full GCs in a single pod, and walked through the detailed troubleshooting steps—including top, thread analysis, jstack, and code fixes—that resolved the issue.
When a production container suddenly hit 90% CPU, the author traced the issue to abnormal JVM garbage‑collection activity, captured the problematic GC graphs, and used Linux tools, jstack, and code inspection to pinpoint a faulty Excel export loop that caused excessive GC and full‑GC cycles.
This article explains how a JDK bug in ScheduledExecutorService can cause a thread pool with coreSize 0 to enter a tight loop, driving CPU usage to 100 %, and shows the fixes introduced in JDK 9 as well as a related bug in scheduleWithFixedDelay.
The article investigates a CPU load spike caused by a red‑black tree cycle inside Java's HashMap after JDK 8, detailing monitoring steps, stack‑trace analysis, heap dump inspection, and concluding with a recommendation to replace HashMap with ConcurrentHashMap in concurrent scenarios.
