Zero-Downtime Deployment Strategies with PM2 and Docker Swarm for Kenyan Tech Startups

Graceful Process Termination: Handling SIGINT and SIGTERM

When deploying new versions, killing running processes abruptly drops active customer checkouts and database transactions. Applications must capture termination signals, stop accepting new connections, and finish active work before exiting:

process.on('SIGTERM', () => {
    console.log('Received SIGTERM, closing HTTP server...');
    server.close(() => {
        console.log('HTTP server closed, closing database pools...');
        db.end(() => {
            process.exit(0);
        });
    });
});