当涉及到EC2的连接性问题时，您几乎不需要检查什么即可找到根本原因。

• SSH进入应用程序正在运行的EC2实例，并确保您可以从EC2实例中访问它。如果可行，则需要解决与网络相关的问题。


• 如果第1步成功。现在，您已经确定要解决此问题是网络问题，您需要检查以下内容。
  
  
  
  
  • 检查是否已创建Internet网关并将其连接到您的VPC。
  
  
  • 接下来检查您的子网路由表是否具有指向互联网网关的默认路由。检查此链接即可完成此操作和
  
  
  • 检查您的子网网络ACL 规则，以查看端口是否未被阻塞
  
  
  • 最后，您希望检查显示的实例安全性组。
  
  

如果您需要通过EC2 dns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，或尝试设置新实例。

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 React\Socket\ConnectionException: 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): React\Socket\Server->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): Ratchet\Server\IoServer::factory(Object(Ratchet\Http\HttpServer), 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 Ratchet\Server\IoServer;
use Ratchet\Http\HttpServer;
use Ratchet\WebSocket\WsServer;
use MyApp\Chat;

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.