使用 PM2 管理进程
学习使用 PM2 管理、监控和扩展生产环境中的 Node.js 应用程序。
使用 PM2 管理进程 是 CoddyKit 上的免费 Node.js Backend Development Bootcamp 课时。 这是第 3 节课，共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 Node.js Backend Development Bootcamp 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Node.js Backend Development Bootcamp 课程共包含 4 节课。
本课时的部分内容尚未翻译，以英文显示。
What is PM2?
Welcome to process management with PM2! PM2 stands for Process Manager 2, and it's a powerful tool for Node.js applications.
In production, you need your application to run reliably, restart if it crashes, and utilize server resources efficiently. PM2 handles all of this.
- Keep Alive: Automatically restarts your app if it crashes.
- Monitoring: Provides insights into your app's performance.
- Scaling: Easily run multiple instances of your app for better performance.
Installing PM2 Globally
Getting started with PM2 is straightforward. You install it globally using npm, so it's available as a command-line tool on your system.
Open your terminal and run the following command:
npm install -g pm2
This command installs the PM2 CLI (Command Line Interface) globally, allowing you to use pm2 commands from any directory.
Starting Your First App
Once installed, you can start any Node.js application with a simple command. PM2 will keep it running in the background, even if your terminal closes!
First, here's a basic Node.js server:
const http = require('http');
const server = http.createServer((req, res) => {
res.writeHead(200, { 'Content-Type': 'text/plain' });
res.end('Hello from PM2!\n');
});
const PORT = 3000;
server.listen(PORT, () => {
console.log(`Server running on port ${PORT}`);
});Launching with PM2
To start the server from the previous scene (let's say it's saved as app.js) with PM2, you'd run:
pm2 start app.js --name my-first-app
The --name flag gives your process a friendly identifier. PM2 will then list your running application, showing its status, uptime, and other details.
If your app crashes, PM2 will automatically restart it, ensuring high availability!
Monitoring Your Processes
PM2 offers excellent tools to monitor your running applications. You can quickly see a list of all managed processes and their statuses.
pm2 list: Shows a table of all your PM2-managed processes, including their ID, name, status, CPU usage, memory usage, and uptime.pm2 monit: Provides a dashboard-like view in your terminal, displaying real-time CPU, memory, and log data for all your applications. It's great for quick health checks.
Stopping & Restarting Apps
Managing the lifecycle of your applications is simple with PM2. You can stop, restart, or delete processes using their name or ID.
pm2 stop my-first-app: Stops the application named 'my-first-app'.pm2 restart my-first-app: Restarts the application. Useful after code changes.pm2 delete my-first-app: Stops the application and removes it from PM2's process list.pm2 stop all: Stops all running applications managed by PM2.
These commands give you full control over your deployed Node.js services.
Using a Configuration File
For more complex setups or managing multiple applications, PM2 allows you to use a configuration file (e.g., ecosystem.config.js). This file defines your applications, environment variables, and other settings.
Here's a simple app for demonstration:
const http = require('http');
const port = process.env.PORT || 3001;
http.createServer((req, res) => {
res.writeHead(200, { 'Content-Type': 'text/plain' });
res.end(`Hello from config app on port ${port} (PID: ${process.pid})!\n`);
}).listen(port, () => {
console.log(`Config demo server running on port ${port}`);
});Ecosystem Config Example
Now, let's define an ecosystem.config.js to manage this app:
module.exports = {
apps : [{
name: "my-config-app",
script: "app-config-demo.js",
instances: 1,
exec_mode: "fork",
env: {
NODE_ENV: "development",
PORT: 3001
},
env_production: {
NODE_ENV: "production",
PORT: 80
}
}]
};
To start this app using the config file, you'd run: pm2 start ecosystem.config.js. This is great for version control and consistent deployments.
Scaling with Clustering Mode
Node.js is single-threaded, but modern servers have multiple CPU cores. PM2's clustering mode allows you to run multiple instances of your app, distributing the load across all available cores.
Here's a simple app that shows its process ID:
const http = require('http');
const process = require('process');
const server = http.createServer((req, res) => {
res.writeHead(200, { 'Content-Type': 'text/plain' });
res.end(`Hello from instance ${process.pid}!\n`);
});
const PORT = 3002;
server.listen(PORT, () => {
console.log(`Cluster server ${process.pid} running on port ${PORT}`);
});Running in Cluster Mode
To start the app from the previous scene (e.g., app-cluster.js) in cluster mode, you can use:
pm2 start app-cluster.js -i max
The -i max flag tells PM2 to launch as many instances as your CPU has cores. PM2 will then act as a load balancer, distributing incoming requests among these instances. This significantly improves performance and resilience.
PM2 Quick Check
You've learned how to manage, monitor, and scale your Node.js applications with PM2. Let's test your understanding!
Recap & Next Steps
Great job! You've successfully learned the fundamentals of process management with PM2.
PM2 is an essential tool for deploying and maintaining Node.js applications in production, offering features like automatic restarts, monitoring, and easy scaling through clustering.
Keep exploring PM2's documentation for more advanced features, such as log management, startup scripts, and custom metrics. Happy deploying!
常见问题解答
「使用 PM2 管理进程」课时是免费的吗？
是的 — 「使用 PM2 管理进程」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Node.js Backend Development Bootcamp 课程的其余内容，请升级到 CoddyKit PRO。 Node.js Backend Development Bootcamp 课程共包含 4 节课。
「使用 PM2 管理进程」这节课中我会学到什么？
学习使用 PM2 管理、监控和扩展生产环境中的 Node.js 应用程序。 你通过在浏览器中直接运行的动手代码来练习 Node.js Backend Development Bootcamp，全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 Node.js Backend Development Bootcamp 需要有经验吗？
无需任何先前经验。CoddyKit 上的 Node.js Backend Development Bootcamp 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。 这是第 3 节课，共 4 节。
「使用 PM2 管理进程」课时需要多长时间？
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。
我能在这节 Node.js Backend Development Bootcamp 课中编写并运行代码吗？
能。每节 Node.js Backend Development Bootcamp 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。