多EC2实例部署网站：是否需在各实例配置Apache、PHP及MySQLi？

Hey there! Great question as you're getting started with building a scalable web setup on AWS. Let's break down exactly what you need to do for each component:

Web & Application Components (Apache + PHP) #

Yes, every EC2 instance behind your load balancer will need to have Apache (or your preferred web server) and PHP installed. Here's why:

• The load balancer only handles routing incoming traffic to your EC2 instances—it doesn't process the web content or run your PHP code. Each instance needs to be able to receive HTTP requests, serve static assets, and execute your PHP applications independently.
• To make this easier (especially if you plan to add more instances later with Auto Scaling), I recommend creating a custom Amazon Machine Image (AMI) that already has Apache, PHP, and your application code pre-configured. Alternatively, use tools like Ansible or AWS CloudFormation to automate the setup when instances launch.

Database Component (MySQLi) #

This part needs a bit more clarification:

• MySQLi is a PHP extension—so you do need to have this extension installed on every EC2 instance that runs PHP code (since it's how your PHP app connects to a MySQL database).
• However, you should NOT install a full MySQL server on each EC2 instance. Here's the problem with that approach:
  • Data inconsistency: User data (like form submissions, user accounts) would only live on the instance where it was created, so other instances wouldn't see it.
  • Maintenance overhead: You'd have to handle data syncing, backups, and scaling across multiple MySQL servers, which gets complicated fast.
• The better approach for AWS is to use Amazon RDS (Relational Database Service) to host your MySQL database. RDS is a managed service that handles backups, high availability, scaling, and security for you. All your EC2 instances will connect to this single RDS instance using MySQLi, ensuring all instances access the same consistent data.

Quick Additional Tip #

Make sure your load balancer is configured with health checks—this way, it will only send traffic to EC2 instances that are healthy (i.e., Apache/PHP are running properly).

内容的提问来源于stack exchange，提问作者Ahmed