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What should be PID 1 in a container?

Submitted by Ranjith Rajaram (@rrajaram) on Mar 3, 2017

Section: Crisp talk of 15 mins duration Technical level: Intermediate Status: Confirmed & Scheduled


In a traditional unix systems, PID 1 is usually the init/systemd process. When a container is started, the application becomes PID 1 in its assigned namespace. So the question that arises is ” Does it really matter which process becomes PID 1 inside a container ?”. PID 1 usually has different roles to play. This talk “What should be PID 1 in a container ?” will discuss about the problem related to process reaping and signal handling. This talk would be beneficial for developers who are planning to containerize the application. Problem related to process reaping,signal handling will be explained with a simple example.


  1. Quick look at the CMD directive Dockerfile [1 minute]
  2. Demo to visualize the problem [4 minutes]
  3. Discussion on Process reaping [2 minutes]
  4. Demo to visualize signal handling [2 minutes]
  5. Minimal init/systemd [1 minute]
  6. New feature of Docker 1.13 [1 minute]
  7. Systemd in action [2 minutes]


Prior knowledge of Containers would be a plus

Speaker bio

Ranjith Rajaram works for Red Hat as a Sr. Principal Tech. Support Engineer. He has 13 years of experience in implementing Linux servers for complex workloads. Active member of Fudcon and was involved in the planning of container track for Fudcon 2015.


Preview video


  • Zainab Bawa (@zainabbawa) Crew 3 years ago

    Hi Ranjith, please share link to a preview video explaining your talk, why should the audience attend, and what are the key takeaways.

    • Ranjith Rajaram (@rrajaram) Proposer 3 years ago

      please find the video

  • saurabh hirani (@saurabh-hirani) 3 years ago

    Just thinking out aloud - do you think you’d need 40 mins for this talk or a tight 15 min slot to jump directly into a demo setup would work? Or do you want to cover the entire domain of container-gotchas in 40 mins (in which case you should change the title and broaden the scope of your material). If you think a 15 min slot is good - you can assume that the audience knows what docker is and how to start a container. Also as Zainab pointed out, preview video and slides would be really useful to know more.

  • Ranjith Rajaram (@rrajaram) Proposer 3 years ago (edited 3 years ago)

    30 minutes is what I need. I wont be touching the basics/container-gotchas but just enough for driving the point. I can re-look the presentation by straight away starting with the demo’s and skipping “point 1” mentioned in the outline. This would save 10 minutes.

  • Ranjith Rajaram (@rrajaram) Proposer 3 years ago

    From 30 minutes to 15 minutes. Uploaded new slides

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