PM2
Process Management
Manage Node.js applications with PM2
PM2 Process Management
PM2 is an advanced Node.js process manager for production applications. SkyPort provides a seamless CLI interface for PM2 management.
Starting Applications
Basic Start
# Start a Node.js application
skyport pm2 start app.js --name "my-app"
# Start with custom interpreter
skyport pm2 start app.py --interpreter python --name "python-app"
# Start with npm start
skyport pm2 start "npm start" --name "my-app"
Ecosystem File
For more complex configurations, use an ecosystem.config.js:
module.exports = {
apps: [
{
name: "my-app",
script: "server.js",
instances: 2,
exec_mode: "cluster",
env: {
NODE_ENV: "development",
PORT: 3000,
},
env_production: {
NODE_ENV: "production",
},
error_file: "./logs/error.log",
out_file: "./logs/out.log",
log_date_format: "YYYY-MM-DD HH:mm:ss Z",
merge_logs: true,
},
{
name: "worker",
script: "worker.js",
instances: 1,
exec_mode: "fork",
watch: ["worker.js"],
},
],
};
Start with ecosystem file:
skyport pm2 start ecosystem.config.js
skyport pm2 start ecosystem.config.js --env production
Process Management
List Processes
# View all processes
skyport pm2 list
# View detailed process info
skyport pm2 describe app-name
# View in JSON format
skyport pm2 list --format json
Control Processes
# Start process
skyport pm2 start app.js --name "app"
# Stop process
skyport pm2 stop app-name
# Restart process
skyport pm2 restart app-name
# Delete process
skyport pm2 delete app-name
# Restart all processes
skyport pm2 restart all
# Stop all processes
skyport pm2 stop all
# Delete all processes
skyport pm2 delete all
Logs
View Logs
# View logs
skyport pm2 logs app-name
# Follow logs (tail -f style)
skyport pm2 logs app-name -f
# View last 100 lines
skyport pm2 logs app-name --lines 100
# View error logs
skyport pm2 logs app-name --err
# View all logs
skyport pm2 logs
# Clear logs
skyport pm2 flush
Log Rotation
Configure in ecosystem.config.js:
module.exports = {
apps: [
{
name: "app",
script: "server.js",
instances: 1,
error_file: "./logs/error.log",
out_file: "./logs/out.log",
log_file: "./logs/combined.log",
log_date_format: "YYYY-MM-DD HH:mm:ss Z",
log_size: "10M",
compress: true,
rotate_module: true,
},
],
};
Clustering & Scaling
Cluster Mode
# Start in cluster mode (multiple instances)
skyport pm2 start app.js -i max --name "app"
# Start with specific number of instances
skyport pm2 start app.js -i 4 --name "app"
# View cluster status
skyport pm2 list
Scaling
# Scale up
skyport pm2 scale app-name 4
# Scale down
skyport pm2 scale app-name 2
# View current instances
skyport pm2 describe app-name
Monitoring
View Statistics
# View process statistics
skyport pm2 describe app-name
# Monit dashboard (if available)
skyport pm2 monit
Memory and CPU
# Monitor all processes
skyport pm2 monit
# View in table format
skyport pm2 list
# Get detailed metrics
skyport pm2 describe app-name | grep -E "memory|cpu"
Auto-Restart & Persistence
Auto-Start on System Boot
# Generate startup script
skyport pm2 startup
# Save current process list
skyport pm2 save
# Resurrect processes after system reboot
skyport pm2 resurrect
# Disable auto-start
skyport pm2 unstartup
Watch Files
Watch for file changes and automatically restart:
In ecosystem.config.js:
module.exports = {
apps: [
{
name: "app",
script: "server.js",
watch: ["src"],
ignore_watch: ["node_modules", "logs", ".git"],
watch_delay: 1000,
},
],
};
Or via CLI:
skyport pm2 start app.js --watch
Environment Variables
Per-Environment Configuration
module.exports = {
apps: [
{
name: "app",
script: "server.js",
env: {
NODE_ENV: "development",
PORT: 3000,
DEBUG: "true",
},
env_production: {
NODE_ENV: "production",
PORT: 8080,
DEBUG: "false",
},
},
],
};
Start with environment:
skyport pm2 start ecosystem.config.js --env production
Runtime Environment Variables
# Set environment variable
skyport pm2 start app.js --name "app" --env NODE_ENV=production
# Or use environment file
export NODE_ENV=production
skyport pm2 start app.js --name "app"
Advanced Features
Graceful Reload (Zero-Downtime)
# Reload without stopping service
skyport pm2 reload app-name
# Reload all
skyport pm2 reload all
Handle Signals
// In your application
process.on('SIGTERM', () => {
console.log('SIGTERM received, shutting down gracefully...');
server.close(() => {
process.exit(0);
});
});
Max Memory Restart
In ecosystem.config.js:
module.exports = {
apps: [
{
name: "app",
script: "server.js",
max_memory_restart: "500M", // Restart if exceeds 500MB
},
],
};
Troubleshooting
Process Won't Start
# Check error logs
skyport pm2 logs app-name --err
# Try running directly
node app.js
# Check dependencies
npm install
High Memory Usage
# View memory statistics
skyport pm2 describe app-name
# Enable memory restart
skyport pm2 start app.js --max-memory-restart 512M --name "app"
# Profile memory usage
node --inspect app.js
CPU Usage at 100%
# Check what's running
skyport pm2 list
# View detailed stats
skyport pm2 monit
# Look for infinite loops or bugs
skyport pm2 logs app-name -f
Next: Zero-Downtime Deployments | Logs