Node.js app on Kubenetes crashing with error SyntaxError: Unexpected token import for PM2

I have a Node.js application deployed in Kubernetes and my docker file looks like the following:

FROM node:8.9.4
RUN mkdir -p /opt/amy-app-folder
RUN chown -R node:node /opt
WORKDIR /opt/my-app-folder
COPY dist /opt/my-app-folder
RUN npm install pm2 -g
EXPOSE 8000
USER node
CMD ["pm2-docker", "bin/www.js"]

This was working fine until I recently did a deployment for the application. I have configured the CI/CD job in such a way that it will build and deploy the application once I merge the PR to the development branch. When I checked the pods, it is showing CrashLoopBackOff as the status of the pod in which my app is running.

I checked the logs using the command

$kubectl logs -f my-app-name-qa-d8744bf4f-sh6ks -n wea-qa --tail 1000

It is showing the pm2 has been crashed with the following error message

2022-03-21T11:50:46: PM2 log: App [www:0] starting in -fork mode-
2022-03-21T11:50:46: PM2 log: App [www:0] online
/usr/local/lib/node_modules/pm2/lib/ProcessContainerFork.js:30
    import(url.pathToFileURL(process.env.pm_exec_path));
    ^^^^^^
SyntaxError: Unexpected token import
    at createScript (vm.js:80:10)
    at Object.runInThisContext (vm.js:139:10)
    at Module._compile (module.js:607:28)
    at Object.Module._extensions..js (module.js:654:10)
    at Module.load (module.js:556:32)
    at tryModuleLoad (module.js:499:12)
    at Function.Module._load (module.js:491:3)
    at Function.Module.runMain (module.js:684:10)
    at startup (bootstrap_node.js:187:16)
    at bootstrap_node.js:608:3
2022-03-21T11:50:46: PM2 log: App [www:0] exited with code [1] via signal [SIGINT]
2022-03-21T11:50:46: PM2 log: Script /opt/my-appl/bin/www.js had too many unstable restarts (16). Stopped. "errored"
2022-03-21T11:50:50: PM2 log: 0 application online, retry = 3
2022-03-21T11:50:52: PM2 log: 0 application online, retry = 2
2022-03-21T11:50:54: PM2 log: 0 application online, retry = 1
2022-03-21T11:50:56: PM2 log: 0 application online, retry = 0
2022-03-21T11:50:56: PM2 log: Stopping app:www id:0
2022-03-21T11:50:56: PM2 error: app=www id=0 does not have a pid
2022-03-21T11:50:57: PM2 log: PM2 successfully stopped

The only change I have made in the code is to add a console.log and it is removed later. Now, this is the staging version of my application and I checked the code with the master branch, which is running fine in production. There is no change in the code and so I am stuck here and don't know what to do next. As the pod is stopped, I can't go inside the pod and run commands. I redeployed the code again, but still, the pod is starting, and then it is crashed.

I am able to run the code in my local machine and there I am not using Kubernetes or Docker. My node version in local is 12.0.0

Can someone help me to fix this issue? Thanks in advance.

Solution

Here's what I think it's happening with your app:

The problem is not with your app's code

...but with Nodejs not recognizing import when trying to run pm2. The nodejs version v8.x probably does not support importing modules this way.

Now, why this is failing now?

Well, Docker is installing the latest version of pm2 to run your app here:

RUN npm install pm2 -g

Therefore, when you added something to your code, the new build must have downloaded a new version of pm2, one not compatible with that nodejs version. This seems to be similar to this answer: https://stackoverflow.com/a/59840576/1971120

What can you do with this?

From this answer (another question), I would suggest you to upgrade nodejs to +v13 (using a LTS version would be ideal), but in case you can not do that, stick with a compatible pm2 version in the docker descriptor like this:

RUN npm install pm2@x.y.z -g

Where x.y.z is a compatible version.