The architecture of Apache is the organizational and operational model of the Apache web server. Here is a detailed description of the Apache architecture:
Main Process
The main process of Apache, also known as the parent process, is the first process created when Apache starts. This process is responsible for managing the child processes and coordinating requests from clients to the appropriate child processes.
Worker Processes
After being created by the main process, Apache's worker processes are responsible for handling requests from clients. The number of worker processes can be configured to meet performance and resource requirements. Each worker process operates independently and does not share memory with others, which enhances the stability of Apache.
Request Processing Model
Apache uses a standard request processing model, where each worker process waits for requests from clients, processes them, and sends back responses. This request processing model ensures sequential and reliable handling of requests.
Modules
Apache supports numerous modules, known as extensions, which allow adding additional features and functionalities to the server. These modules can work with protocols, handle requests, log events, manage access control, compress data, and perform various other functions.
Virtual Hosts
Apache supports multiple virtual hosts, allowing the hosting of multiple websites on the same physical server. Each virtual host can be configured individually with its own options and settings, enabling easy management of multiple websites independently.
The flexible and powerful architecture of Apache has made it one of the most popular web servers, widely used across the globe to run diverse websites and web applications.