pm2 with systemd and passing node argument

Question

I want to start node with pm2 and environment variables like --nouse-idle-notification or --max-old-space-size=2048.

However, whatever I do, it is not passing the node variables. I start my app with pm2 and a configuration file. The configuration file looks like:

{
  "apps" : [{
    "env": {
      "NODE_PATH": "/usr/bin/node",
      "interpreter_args": "--max-old-space-size=2048 --nouse-idle-notification"
    },
    "env_development": {
      "NODE_ENV": "development"
    },
    "env_production" : {
       "NODE_ENV": "production",
       "APP_TYPE": "web"
    },
    "exec_mode"   : "fork",
    "name"        : "MyApp",
    "script"      : "/opt/myapp/app.js",
    "watch"       : false,
    "out_file"    : "/var/log/app.log",
    "error_file"  : "/var/log/app.log",
    "combine_logs": true,
    "node_args": "--max-old-space-size=2048 --nouse-idle-notification",
    "args": "--max-old-space-size=2048 --nouse-idle-notification"
  }]
}

(as you can see I try to pass in the node variables in multiple ways)

I then start the app with:

pm2 restart pathtojsonfile --env production

Everything is starting up properly and I see variables like "MY_APP" in my code. However, now when I look at the process with "top" I only see:

node /opt/myapp/app.js

When I start the app with forever or manually I can see the process like:

node --max-old-space-size=2048 --nouse-idle-notification /opt/myapp/app.js

Is pm2 just not showing those node arguments or are they really not passed in? (The pm2 started process uses less memory)

Yogi

Include the contents of the systemd .service file you are using with pm2. – Bilodeau

Answer 1

By using "node_args": "--max-old-space-size=2048 --nouse-idle-notification" you did the right thing and these arguments are taken into account.

PM2 renames the process and drop the specified node argument in the process title.

Harpsichord

You can do also pm2 show <app_name>to display node.js argument – Harpsichord

Yes, I did. But was really confused because the params didn't show up in the process itself, i.e. "top". – Yogi

Answer 2

Below is extact command to start pm2 with node-args

pm2 start app.js --node-args="--max-old-space-size=4096"

Lastly

Answer 3

I could not get it to work with pm2 and node_args.

When I switched to setting the environment variable

     NODE_OPTIONS="--max-old-space-size=7200"

it started working.

Quitrent