Web server is an application which delivers web contents as they are requested. It uses a client-server model. Its main function is to provide web pages to clients using HTTP.
How does it work?
- When a web user requests a URL to be loaded, the web server fetches it then sends it to the user's browser.
Apache
Apache is an HTTP web server application that provides a full range of web server features. It is a free software distributed by Apache Software Foundation. It was originally designed for Unix environments, but has been eventually ported to Windows and other OS.
- Installation
In Linux, just type sudo apt-get install apache2 on your terminal. Wait for it to be downloaded and installed.
- Configuration
Once installed, look for httpd.conf (configuration file) in /etc/httpd/conf directory. Use a text editor to edit the file.
You may check if Apache is properly installed and configured by opening in a web browser the file index.html located at /var/www directory.
High Availability
It is a system or component that is continuously operational for a long period of time. This refers to the ability of system to be "100% operational" or "never-failing".
- For a 3-year old child: A girl broke or lost her favorite doll. She cried hard because it was really her favorite. To stop her from crying, her parents bought her another doll which looked like the same as the old one that the girl did not even mind.
Heartbeat
It is used to observe and manage the web servers. When the active server fails to deliver the web page a client has requested, another (passive) web server must take over.
- Installation
In Linux, just type sudo apt-get install heartbeat on your terminal. Wait for it to be downloaded and installed.
Cluster Resource Manager (Pacemaker)
It achieves maximum availability for your clusters services by detecting and recovering from node and resource-level failures by using the functions provided by a cluster infrastructure (example: Heartbeat).
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