OOM Killer

Definitions

1. Out-of-Memory Killer — a Linux kernel mechanism that selects and terminates processes when the system runs critically low on memory, preventing a complete system hang. Scores processes based on memory usage, nice value, and whether they're root-owned. Notorious for killing important processes seemingly at random. In Kubernetes, OOM-killed containers are restarted automatically.

   In plain English: Linux's emergency mechanism that kills processes when the system runs out of memory, often the most surprising 3am alert.

   Example: "The Java process got OOM-killed at 3am — it was using 14GB on a 16GB host. Set -Xmx or increase the container memory limit."

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