当涉及到 EC2 的连接问题时，您只需检查几件事即可找到根本原因.

• 通过 SSH 连接到应用程序正在运行的 EC2 实例，并确保您可以从 EC2 实例内访问它.如果它有效，那么它是我们需要解决的与网络相关的问题.
• 如果第 1 步成功.您现在已经确定这是一个网络问题来解决这个问题，您需要检查以下内容.
  • 检查互联网网关是否已创建并附加到您的 VPC.
  • 接下来检查您的子网路由表是否有指向 Internet 网关的默认路由.检查此链接以完成此操作和以上步骤.
  • 检查您的子网 网络 ACL查看端口是否未被阻塞的规则
  • 最后，您需要检查您显示的实例安全组.

如果您需要通过 EC2 dns 进行访问，则需要在 公共子网 并分配一个弹性IP

如果问题仍然存在，请检查 EC2 状态检查通过，或尝试配置新实例.

As I tried to run the chat app from localhost connected to MySQL database which had been coded with PHP via WebSocket it was successful.

Also when I tried to run from the PuTTY terminal logged into SSH credentials, it was displaying as Server Started with the port# 8080

ubuntu@ec3-193-123-96:/home/admin/web/ec3-193-123-96.eu-central-1.compute.amazonaws.com/public_html/application/libraries/server$ php websocket_server.php
PHP Fatal error: Uncaught ReactSocketConnectionException: Could not bind to tcp://0.0.0.0:8080: Address already in use in /home/admin/web/ec3-193-123-96.eu-central-1.compute.amazonaws.com/public_html/application/libraries/vendor/react/socket/src/Server.php:29
Stack trace:
#0 /home/admin/web/ec3-193-123-96.eu-central-1.compute.amazonaws.com/public_html/application/libraries/vendor/cboden/ratchet/src/Ratchet/Server/IoServer.php(70): ReactSocketServer->listen(8080, '0.0.0.0')
#1 /home/admin/web/ec3-193-123-96.eu-central-1.compute.amazonaws.com/public_html/application/libraries/server/websocket_server.php(121): RatchetServerIoServer::factory(Object(RatchetHttpHttpServer), 8080)
#2 {main}
thrown in /home/admin/web/ec3-193-123-96.eu-central-1.compute.amazonaws.com/public_html/application/libraries/vendor/react/socket/src/Server.php on line 29
ubuntu@ec3-193-123-96:/home/admin/web/ec3-193-123-96.eu-central-1.compute.amazonaws.com/public_html/application/libraries/server$

So I tried to change the port#8080 to port# 8282, it was successful

ubuntu@ec3-193-123-96:/home/admin/web/ec3-193-123-96.eu-central-1.compute.amazonaws.com/public_html/application/libraries/server$ php websocket_server.php

Keeping the shell script running, open a couple of web browser windows, and open a Javascript console or a page with the following Javascript:

var conn = new WebSocket('ws://0.0.0.0:8282');
conn.onopen = function(e) {
    console.log("Connection established!");
};

conn.onmessage = function(e) {
    console.log(e.data);
};

From the browser console results:

WebSocket connection to 'ws://5.160.195.94:8282/' failed: Error in connection establishment: net::ERR_CONNECTION_TIMED_OUT

websocket_server.php

<?php
use RatchetServerIoServer;
use RatchetHttpHttpServer;
use RatchetWebSocketWsServer;
use MyAppChat;

require dirname(__DIR__) . '/vendor/autoload.php';

$server = IoServer::factory(
   new HttpServer(
     new WsServer(
          new Chat()
    )
   ),
   8282
);
$server->run();

I even tried to assign Public IP and Private IP, but with no good it resulted in the same old result?

This was the composer files generated after executing and adding src folder $composer require cboden/ratchet

composer.json(On AmazonWebServer)

{
    "autoload": {
        "psr-4": {
            "MyApp\": "src"
        }
    },
    "require": {
        "cboden/ratchet": "^0.4.1"
    }
}

composer.json(On localhost)

{
    "autoload": {
        "psr-4": {
            "MyApp\": "src"
        }
    },
    "require": {
        "cboden/ratchet": "^0.4.3"
    }
}

How am I suppose to resolve/overcome while connecting it from the WebSocket especially from the hosted server with the domain name such as http://ec3-193-123-96.eu-central-1.compute.amazonaws.com/

var conn = new WebSocket('ws://localhost:8282');

From the Security Group

• Under Inbound tab

• Under Outbound tab

When it comes to a connectivity issue with an EC2 there are few things you need to check to find the root cause.

• SSH into the EC2 instance that the application is running and make sure you can access it from within the EC2 instance. If it works then its a network related issue that we need to solve.
• If step 1 was successful. You have now identified it is a network issue to solve this you need to check the following.
  • Check if an Internet Gateway is created and attached to your VPC.
  • Next check if your subnets routing table has its default route pointing to the internet gateway. check this link to complete this and the above step.
  • Check your subnets Network ACLs rules to see if ports are not blocked
  • finally, you would want to check your Instances Security group as you have shown.

If you need access via a EC2 dns you will need to provision your ec2 instance in a public subnet and assign an elastic IP

If an issue still exists check if the EC2 status checks pass, or try provisioning a new instance.