pm2 and Environments

On a plain Linux VM (GCP, AWS EC2, DigitalOcean), pm2 keeps the app running, restarts it on crash and can run one process per CPU core.

ecosystem.config.js

module.exports = {
  apps: [
    {
      name: 'shopease-api',
      script: 'dist/main.js',
      instances: 'max',            // one per CPU core
      exec_mode: 'cluster',
      max_memory_restart: '512M',
      env_production: { NODE_ENV: 'production', PORT: 3000 },
      env_staging: { NODE_ENV: 'production', PORT: 3100 },
    },
  ],
};

Example

npm ci && npm run build && npx prisma migrate deploy
pm2 start ecosystem.config.js --env production
pm2 status

Example output

[PM2] Starting /srv/shopease-api/dist/main.js in cluster_mode (4 instances)
[PM2] Done.
┌────┬────────────────┬─────────┬──────┬────────┬────────┬──────────┐
│ id │ name           │ mode    │ ↺    │ status │ cpu    │ memory   │
├────┼────────────────┼─────────┼──────┼────────┼────────┼──────────┤
│ 0  │ shopease-api   │ cluster │ 0    │ online │ 0%     │ 92.4mb   │
│ 1  │ shopease-api   │ cluster │ 0    │ online │ 0%     │ 90.1mb   │
│ 2  │ shopease-api   │ cluster │ 0    │ online │ 0%     │ 91.7mb   │
│ 3  │ shopease-api   │ cluster │ 0    │ online │ 0%     │ 89.8mb   │
└────┴────────────────┴─────────┴──────┴────────┴────────┴──────────┘

Tip: Use pm2 reload shopease-api for zero-downtime deploys (instances restart one by one), and put nginx in front for HTTPS and gzip.

Setting	Development	Staging	Production
Source of config	`.env.local`	CI secrets	Secret manager
Database	Docker on laptop	Small managed DB	Managed DB with backups and replicas
Logs	Pretty text, debug	JSON, debug	JSON, info
Swagger `/docs`	On	On	Off or behind auth
CORS origins	localhost	staging domain	shopease.in only

Running on a VM with pm2

Example

One Build, Many Environments