Question

我在node.js中练习集群我有两个核心CPU。我创建了两个worker，每个worker都运行一个简单的http服务器。服务器响应回调将阻塞5秒，以便向其他工作人员发出下一个请求。为了验证工作者是否并行工作，我在Firefox中打开了多个选项卡并刷新了每个选项卡。问题始终是（99％）只有一个工作人员正在响应刷新标签所做的请求。一名工作人员只提供一个请求，并且在该工作人员完成之前阻止所有其他请求。我的代码在这里代码：

var cluster = require('cluster');
var http = require('http');



if (cluster.isMaster) {
    var cpus = require('os').cpus().length;
    console.log('No of cpus:' + cpus);
    console.log(require('os').cpus());

    for (var i = 0; i < cpus; i++) {
        cluster.fork();
    }

    cluster.on('fork', function(worker) {
        console.log('worker:' + worker.id + " is forked");
    });
    cluster.on('online', function(worker) {
        console.log('worker:' + worker.id + " is online");
    });
    cluster.on('listening', function(worker) {
        console.log('worker:' + worker.id + " is listening");
    });
    cluster.on('disconnect', function(worker) {
        console.log('worker:' + worker.id + " is disconnected");
    });
    cluster.on('exit', function(worker) {
        console.log('worker:' + worker.id + " is dead");
    });

} else {
    http.createServer(function(req, res) {

        console.log('worker:' + cluster.worker.id + " going to send response ");
        res.writeHead(200);
        res.end("hello world. worker: " + cluster.worker.id);
        var stop = new Date().getTime();
        while (new Date().getTime() < stop + 5000) {;
        }
    }).listen(8000);
}

输出：

20 Aug 00:36:11 - [nodemon] restarting due to changes...
20 Aug 00:36:12 - [nodemon] starting `node cluster.js`
No of cpus:2
[ { model: 'Intel(R) Core(TM)2 Duo CPU     E4500  @ 2.20GHz',
    speed: 2200,
    times: { user: 2264671, nice: 0, sys: 698343, idle: 5965109, irq: 98812 } },
  { model: 'Intel(R) Core(TM)2 Duo CPU     E4500  @ 2.20GHz',
    speed: 2200,
    times: { user: 2466000, nice: 0, sys: 502562, idle: 5959203, irq: 4609 } } ]
worker:1 is forked
worker:2 is forked
worker:2 is online
worker:1 is online
worker:2 is listening
worker:1 is listening
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response
worker:1 going to send response

我注意到了一件事。如果我强制重新加载（ctrl + f5）选项卡，那么两个工作人员都会一个接一个地响应。输出：

worker:1 going to send response
worker:2 going to send response
worker:1 going to send response
worker:2 going to send response
worker:1 going to send response
worker:2 going to send response
worker:1 going to send response
worker:2 going to send response
worker:1 going to send response
worker:2 going to send response
worker:1 going to send response
worker:2 going to send response
worker:1 going to send response
worker:2 going to send response
worker:1 going to send response
worker:2 going to send response
worker:1 going to send response
worker:2 going to send response
worker:1 going to send response
worker:2 going to send response
worker:1 going to send response
worker:2 going to send response
worker:2 going to send response
worker:1 going to send response
worker:2 going to send response
worker:1 going to send response
worker:2 going to send response
worker:1 going to send response
worker:2 going to send response

我很困惑这里发生的正常刷新（f5）和强制重装（ctrl + f5）。帮我解决一下......！

Answer 1

表面节点群集上的TIL似乎没有像它所说的那样做（至少对我而言）。

我遇到了同样的情况，当我从浏览器同步生成请求时，观察同一个工作进程总是被请求。我的一位同事用提琴手一次重播约20个请求。当所有这些请求以非常快的速度到达服务器时，比集群管理器更快地将它们传递给工作人员（我猜），那么您将看到通过请求调用其他工作程序。

似乎一旦经理将请求移交给工人，它就不知道/关心工人阻塞。它只知道管道中只有一个请求，并且没有必要将该请求提供给第一个工作人员以外的任何人，因为就经理所知，他是可用的。

Answer 2

您的响应代码中的while循环可能会导致一些严重问题。如果要模拟长时间运行的请求，则应该在那里使用setTimeout。

请为您的员工尝试此操作：

http.createServer(function(req, res) {
    console.log('worker:' + cluster.worker.id + " going to send response ");
    setTimeout(function() {
       res.writeHead(200);
       res.end("hello world. worker: " + cluster.worker.id);
    }, 5000);
}).listen(8000);

话虽如此，@ dandavis在评论中说的是真的：cluster不进行循环负载平衡，因此，只要Worker 1可用于请求，它就会处理它们。像我建议的那样使用setTimeout实际上会让您的工作人员更多可以处理请求，因此您可能只会看到Worker 1处理请求＃39;只是从浏览器手动点击服务器。您可能需要某种负载测试脚本来查看两个工作人员处理请求。

至于你在 F5 和 CTRL-F5 之间看到的差异，我最好的猜测是你的浏览器保持与服务器的连接，所以，当您只使用 F5 时，它使用相同的连接，该连接将始终发送给同一个工作人员。当您使用 CTRL-F5 时，它实际上关闭了之前的连接，因此可以在下次请求时连接到任一工作人员。

node.js中的群集无法正常工作。只有一名工人总是在回应

2 个答案: