How to setup pm2-logrotate for docker with nodejs running pm2? - docker

Question

I have the docker image from keymetrics/pm2:8-jessie and running my nodejs application well with pm2. I tried to add pm2-logrotate for sizing the log with date. I added the following in my Dockerfile. The module pm2-logrotate can be started but the Target PID is null. Anyone can help please?
FROM keymetrics/pm2:8-jessie
RUN npm install
RUN pm2 install pm2-logrotate
RUN pm2 set pm2-logrotate:retain 90
RUN pm2 set pm2-logrotate:dateFormat YYYY-MM-DD_HH-mm-ss
RUN pm2 set pm2-logrotate:max_size 10M
RUN pm2 set pm2-logrotate:rotateInterval 0 0 * * *
RUN pm2 set pm2-logrotate:rotateModule true
RUN pm2 set pm2-logrotate:workerInterval 10
ENV NODE_ENV=$buildenv
ENV NPM_CONFIG_LOGLEVEL warn
CMD ["sh", "-c", "pm2-runtime start pm2.${NODE_ENV}.config.js"]
pm2 ls
┌──────────────┬────┬─────────┬─────────┬─────┬────────┬─────────┬────────┬─────┬────────────┬──────┬──────────┐
│ App name │ id │ version │ mode │ pid │ status │ restart │ uptime │ cpu │ mem │ user │ watching │
├──────────────┼────┼─────────┼─────────┼─────┼────────┼─────────┼────────┼─────┼────────────┼──────┼──────────┤
│ app_server │ 1 │ 1.0.0 │ cluster │ 150 │ online │ 1 │ 2h │ 0% │ 104.4 MB │ root │ disabled │
└──────────────┴────┴─────────┴─────────┴─────┴────────┴─────────┴────────┴─────┴────────────┴──────┴──────────┘
Module
┌───────────────┬────┬─────────┬─────┬────────┬─────────┬─────┬───────────┬──────┐
│ Module │ id │ version │ pid │ status │ restart │ cpu │ memory │ user │
├───────────────┼────┼─────────┼─────┼────────┼─────────┼─────┼───────────┼──────┤
│ pm2-logrotate │ 2 │ 2.7.0 │ 205 │ online │ 0 │ 0% │ 44.5 MB │ root │
└───────────────┴────┴─────────┴─────┴────────┴─────────┴─────┴───────────┴──────┘

Answer 1

One reason is as pm2 logrotate is not the primary process of the Docker container, but a managed process by pm2, so you can verify this behaviour by stopping main process that is defined pm2.${NODE_ENV}.config.js your container will die no matter if pm2-logrotate is running.
Also, I do not think it should be null, it should be something like
pm2 ls
┌─────┬──────────────────┬─────────────┬─────────┬─────────┬──────────┬────────┬──────┬───────────┬──────────┬──────────┬──────────┬──────────┐
│ id │ name │ namespace │ version │ mode │ pid │ uptime │ ↺ │ status │ cpu │ mem │ user │ watching │
├─────┼──────────────────┼─────────────┼─────────┼─────────┼──────────┼────────┼──────┼───────────┼──────────┼──────────┼──────────┼──────────┤
│ 1 │ www │ default │ 0.0.0 │ fork │ 26 │ 13s │ 0 │ online │ 0% │ 40.3mb │ root │ disabled │
└─────┴──────────────────┴─────────────┴─────────┴─────────┴──────────┴────────┴──────┴───────────┴──────────┴──────────┴──────────┴──────────┘
Module
┌────┬───────────────────────────────────────┬────────────────────┬───────┬──────────┬──────┬──────────┬──────────┬──────────┐
│ id │ module │ version │ pid │ status │ ↺ │ cpu │ mem │ user │
├────┼───────────────────────────────────────┼────────────────────┼───────┼──────────┼──────┼──────────┼──────────┼──────────┤
│ 0 │ pm2-logrotate │ 2.7.0 │ 17 │ online │ 0 │ 0.5% │ 43.1mb │ root │
└────┴───────────────────────────────────────┴────────────────────┴───────┴──────────┴──────┴──────────┴──────────┴──────────┘
Also will suggest to use the alpine base image as the above image seem very heavy, the below image is 150MB while the above image is arround 1GB.
FROM node:alpine
RUN npm install pm2 -g
RUN npm install
RUN pm2 install pm2-logrotate
RUN pm2 set pm2-logrotate:retain 90
RUN pm2 set pm2-logrotate:dateFormat YYYY-MM-DD_HH-mm-ss
RUN pm2 set pm2-logrotate:max_size 10M
RUN pm2 set pm2-logrotate:rotateInterval 0 0 * * *
RUN pm2 set pm2-logrotate:rotateModule true
RUN pm2 set pm2-logrotate:workerInterval 10
ENV NODE_ENV=$buildenv
ENV NPM_CONFIG_LOGLEVEL warn
WORKDIR /app
COPY . /app
CMD ["sh", "-c", "pm2-runtime start confi"]