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node.jstypescriptparameterscronpm2

How to startup PM2 with multiple instances

I am running my nodejs code via PM2. For my project I need multiple instances of nodejs that running the same code. So I created a next script "myscript.sh":

cd ~/myproject    
PM2_HOME='.pm2_1' /usr/local/bin/node /usr/local/lib/node_modules/pm2/bin/pm2 start dist/app.js -- id=1 token=xxx isMaster=true
PM2_HOME='.pm2_2' /usr/local/bin/node /usr/local/lib/node_modules/pm2/bin/pm2 start dist/app.js -- id=1 token=yyy isMaster=false
. . .
PM2_HOME='.pm2_x' /usr/local/bin/node /usr/local/lib/node_modules/pm2/bin/pm2 start dist/app.js -- id=1 token=zzz isMaster=false

It works when I run it via CLI like bash myscript.sh, but it doesn't work via crontab:

@reboot bash /home/user/myproject/myscript.sh

or

* * * * * bash /home/user/myproject/myscript.sh

Also I tried to use pm2 startup but it doesn't work with the PM2_HOME='..' parameter, no matter what I set to PM2_HOME, like .pm2_1, it still creates environment like /home/user/myproject/.pm2. Seems like pm2 startup works for the single instances only.

So my question how can I run myscript.sh via crontab?

I don't know if it relevant my code is written in TS. On localhost I run it like this:

npm start -- id=1 token=zzz isMaster=false

where start is set in package.json:

"start": "npm run build && node dist/app"
"build": "rimraf dist && tsc"

Please notice that

  1. Every instance should get different parameters
  2. Solution should work for the startup case, like the app should startup with a machine start
Solution

  • To have PM2 run multiple instances of your node app you'll want to use clustered mode.

    See the docs here: https://pm2.keymetrics.io/docs/usage/cluster-mode/

    For example, you can use this command to start 4 instances of your app:

    pm2 start app.js -i 4

    --- EDIT ---

    For providing different input parameters per process I don't think there is any easy way to do that with PM2.

    An alternative is to create a new JavaScript/TypeScript file as your entry point. Have that entry point create multiple child processes, each of which is your application. Then you could pass in different parameters for each.