---
title: Containerized zombie spawner
date: 2015-08-12 21:21:13
tags: [docker]
---

Recently I was playing with a fully Dockerized setup of Jenkins at work
and found a curious issue there. Whenever Jenkins was polling the git
server the side effect was that it created a zombie ssh process. The
issue is actually
[remediated](https://github.com/jenkinsci/docker/issues/54) by the
Jenkins team now by [explicitly using](https://github.com/jenkinsci/docker/commit/d5aea67dcae9d62fe4ca6ad961ffe66f65d9a591)
a tiny init system called ... [tini](https://github.com/krallin/tini) started as the main
container's process instead of just starting Jenkins there. This tiny
tini thing can properly adopt and reap the children. I was all like -
wow, what a great blog entry is coming at me. I was planning to describe
how zombies come to existence on Linux and why Docker should, in my
opinion, provide an adopter-reaper by default and other very interesting
things ! But then I found a really excellent article by the
[Phusion](http://www.phusion.nl/) team
[here](https://blog.phusion.nl/2015/01/20/docker-and-the-pid-1-zombie-reaping-problem/)
explaining all that and more. It is very good. You should read it. That
is it. The end. Happy reaping !