I am using Express js and Node-cluster for taking the advantage of clustering I am also using PM2 for process and memory management. For a single machine, it is working fine, but my machine having 2 cores and I want to make available more cores. So I decided to join 3 more machines and now all 4 machines are connected using LAN. I am able to access the other machines using IP address in web browser also.
Now I want to connect all the machines and want to share their cores so that I will finally have 2 + 6 = 8 cores for my application. How can it possible? Is there any node module available to achieve this? Thanks.
A cluster module executes the same Node. js process multiple times. Therefore, the first thing you need to do is to identify what portion of the code is for the master process and what portion is for the workers.
Node. js runs single threaded programming, which is very memory efficient, but to take advantage of computers multi-core systems, the Cluster module allows you to easily create child processes that each runs on their own single thread, to handle the load.
Essentially, the nodes share resources with each other and act as a single powerful machine -- the cluster.
To address these issues, Node. JS uses a single thread with an event-loop. In this way, Node can handle 1000s of concurrent connections without any of the traditional detriments associated with threads.
Node-cluster is good for taking advantage of multi core processors, but when it comes to horizontal scaling(adding more machines), you'll need to use load balancers or reverse proxy. For reverse proxy you can use any web server like Apache or nginx. If you want to rely on node and npm, there is a module by nodejitsu: http-proxy. Here is an example for http proxy for 3 machines running your node app.
New version:
npm install --save http-proxy
If you prefer older version:
npm install --save [email protected]
For version 1.x.x (New)
server.js
var http = require('http'),
httpProxy = require('http-proxy');
var addresses = [
{
host: "localhost",
port: 8081
},
{
host: "localhost",
port: 8082
},
{
host: "localhost",
port: 8083
}
];
//Create a set of proxy servers
var proxyServers = addresses.map(function (target) {
return new httpProxy.createProxyServer({
target: target
});
});
var server = http.createServer(function (req, res) {
var proxy = proxyServers.shift();
proxy.web(req, res);
proxyServers.push(proxy);
});
server.listen(8080);
for version 0.x.x (Old)
server.js
var proxyServer = require('http-proxy');
var servers = [
{
host: "localhost",
port: 8081
},
{
host: "localhost",
port: 8082
},
{
host: "localhost",
port: 8083
}
];
proxyServer.createServer(function (req, res, proxy) {
var target = servers.shift();
proxy.proxyRequest(req, res, target);
servers.push(target);
}).listen(8080);
Clients making request to 8080 port are unaware of existence of servers at 8081, 8082 and 8083. They make requests to 8080 as if it is the only server and get response from it.
Now, one of the machines in your cluster will work as node balancer and application is hosted on other three machines. IP address of load balancer can be used as public IP.
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