Docker exits with code 0 when using pm2 start

Question

My Dockerfile contains the pm2 start command as follows:

FROM node:10

WORKDIR /usr/src/app

COPY . .

# ...

EXPOSE 8080

CMD [ "pm2", "start", "npm", "--", "start" ]

However the container exits straightaway after pm2 logs successfully starting:

[PM2] Spawning PM2 daemon with pm2_home=/root/.pm2
[PM2] PM2 Successfully daemonized
[PM2] Starting /usr/local/bin/npm in fork_mode (1 instance)
[PM2] Done.

How can I get the container to stay running with pm2?

Answer 1

The problem is that pm2 start runs pm2 as a daemon ("in the background"), which Docker isn't aware of.

You need to use pm2-runtime to make it run in the foreground:

CMD [ "pm2-runtime", "start", "npm", "--", "start" ]

See pm2 "Container integration" docs.