Blog · topic

JVM

Heap, GC, threads and container limits: the JVM as an SRE needs to understand it.

Exit code 137, OOMKilled, and the JVM that fits its heap but not its container

137 = 128 + SIGKILL. How to tell a cgroup OOM kill from a host OOM, why -Xmx equal to the memory limit gets your Java pod killed, and how to size it.

3 Oct 2026 · 2 min read

Observability JVM SRE

p99 latency is 25 seconds and the error rate is zero: histograms, histogram_quantile and timeouts

Slow requests that end in 200 are successes, and abandoned ones are never counted. How to read p99 from Prometheus buckets and find the wait behind it.

3 Oct 2026 · 5 min read