Why Your Docker Containers Refuse to Die: The PID 1 Problem

You hit docker stop. Nothing happens. You wait ten seconds. Docker eventually sends SIGKILL. The container disappears, but only after a frustrating timeout. Your CI pipeline is slower than it should be, your Kubernetes pod terminations are sluggish, and you have a vague feeling something is wrong. I hit this exact issue last month while debugging a deployment that took 90 seconds to roll out a single replica. Turned out to be the same boring culprit I've seen on at least four other projects: th...