Restart Docker container on inner process crash

user_4418836 0
Viewed 9616

Update: Found secret cause - nodemon

The answer is just to set the container to restart on crash. In development, I'm using nodemon which prevents the process from exiting on a crash - so I assumed that the process crashing didn't cause the container to exit. My mistake. The process crashing does in fact cause the container to exit when using node and not nodemon.

{
  "scripts": {
    "development:service": "nodemon ./service/server.js",
    "production:service": "node ./service/server.js"
  }
}

Original Question

How do I restart a docker container when a process inside the container crashes?

Would the best way be to set --autorestart ON_FAILURE for the container and then make the container crash when the inner process crashes? If so, how do I force the container to crash when one of it's process crashes?

I'm using the image node:10.15.3.

Useful Link: how to make a container restart if the container, itself, crashes

Dockerfile

FROM node:10.15.3 

ENV NODE_ENV development

# Create application directory.
RUN mkdir -p /src
WORKDIR /src

# Install app dependencies and build.
ADD . /src
RUN yarn install --force

RUN ["chmod", "+x", "./run.sh"]
CMD [ "./run.sh" ]

Processes (simplified)

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
user        13  0.0  0.1  17952  2840 ?        S    15:09   0:00 bash ./install.sh
user        72  0.5  3.2 889668 66728 ?        Sl   15:09   0:00 /usr/local/bin/node /opt/yarn-v1.13.0/bin/yarn.js start 
user        97  2.4  3.2 919992 65748 ?        Sl   15:09   0:01 /usr/local/bin/node ./service/server.js
docker crash exit unix
2 Answers
user_53599530

When you run multiple services in a container, and you are very, very sure you want this (it's best practice to run a single process in a single container), you may want a process supervisor (for example systemd) which restart any crashed process inside, or crash if any of it's supervised processes crash.

There are also some other, more lightweight, ways to accomplish this, like a wrapper bash script.

It's all described here: https://docs.docker.com/config/containers/multi-service_container/

Edit after question was updated with Dockerfile:

The easiest way is probably to make sure run.sh crashes if any of it's subprocesses crash. Then the container will crash, and optionally restart if you use --restart=on-failure in docker run.

user_54734090
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