What is a Web Cluster and what is it for?

A web cluster is a system made up of multiple servers that work in a coordinated way to offer a scalable and reliable web service. A web cluster is used to handle very high traffic peaks and ensure high availability of the website.

The advantages of a web cluster for a site with very high traffic peaks are:

• Speed: The servers in the cluster can distribute the workload among them, which means that each server can process requests faster and the site will respond faster to users.
• Responsiveness: if one of the servers in the cluster goes offline, the other servers in the cluster will take its place and the site will continue to operate without interruption.
• Improved Conversions and Sales: A website that is fast and responsive will be able to offer a better user experience, which can increase conversions and ecommerce sales.

Geographic cluster

A geographic web cluster is a set of servers that are located in different geographic locations and that work together to provide a web service. The advantages of using a geographic web cluster over a non-geographic web cluster are:

1. Redundancy: if one of the servers in the cluster should fail, the other servers in the cluster would be able to take its place and continue to provide the service, thus ensuring greater reliability and availability.
2. Better performance: Because the cluster servers are spread across different geographic locations, response times for users who are in close proximity to one of the cluster servers will be shorter than for users who are away from the servers.
3. Scalability: If the workload of the cluster increases, new servers can be easily added to the cluster to handle the extra load, without having to interrupt the service.
4. Security: Since the servers in the cluster are distributed in different geographical locations, it is less likely that a single event, such as an earthquake or a heat wave, could affect all the servers in the cluster at the same time, thus ensuring greater security of the service .

In relation to instability and natural disasters and connectivity problems, the advantages of using a geographical cluster are:

1. Improved reliability: Because the cluster servers are distributed in different geographical locations, it is less likely that a single event, such as an earthquake or heat wave, could affect all the servers in the cluster at the same time. This ensures greater reliability of the service.
2. Increased availability: If one of the servers in the cluster should fail due to a failure or natural disaster, the other servers in the cluster would be able to take over and continue to provide the service, thus ensuring higher availability.
3. Less dependency on connectivity: Should one of the servers in the cluster experience connectivity issues, the other servers in the cluster would be able to continue providing service, reducing the service's dependency on the connectivity of a single server.
4. Increased resiliency: Since the servers in the cluster are distributed in different geographical locations, it is less likely that connectivity problems or unexpected events could interrupt the service. This makes the service more resilient and better able to handle the unexpected.

Technologies used to build Web Clusters on Linux

Here are some web clustering technologies for Linux that can be used to create a web cluster:

1. Apache HTTP Server: Apache HTTP Server is a very popular open source web server software that supports clustering through the use of modules such as mod_proxy and mod_cluster. It can be found here: https://httpd.apache.org/
2. Nginx: Nginx is open source web server software that supports clustering through the use of modules such as ngx_http_upstream_module. It can be found here: https://www.nginx.com/
3. HAProxy: HAProxy is an open source load balancing software that supports clustering through the use of load balancing algorithms such as round robin and least connections. It can be found here: https://www.haproxy.org/
4. Linux Virtual Server (LVS): As mentioned earlier, Linux Virtual Server is an open source load balancer for Linux that allows you to create a server cluster to distribute the workload among the servers in the cluster. It can be found here: https://www.linuxvirtualserver.org/
5. Keepalived: As mentioned earlier, Keepalived is an open source failover and load balancing software for Linux that allows you to create a server cluster to ensure service availability. It can be found here: https://www.keepalived.org/

Technologies used to build Cluster Database on Linux

Here are some SQL clustering technologies for Linux that can be used to create a SQL cluster:

1. MySQL Cluster: MySQL Cluster is an open source distributed database system that allows you to create a database cluster to ensure database availability and scalability. It can be found here: https://www.mysql.com/products/cluster/
2. MariaDB Galera Cluster: MariaDB Galera Cluster is an open source distributed database system based on MySQL that allows you to create a database cluster to ensure database availability and scalability. It can be found here: https://mariadb.com/products/technologies/mariadb-galera-cluster
3. PostgreSQL Streaming Replication: PostgreSQL Streaming Replication is a real-time replication feature included in PostgreSQL that allows you to create a database cluster to ensure database availability and scalability. It can be found here: https://www.postgresql.org/docs/current/streaming-replication.html
4. Oracle Real Application Clusters (RAC): Oracle RAC is a commercial database clustering solution offered by Oracle that allows you to create a database cluster to ensure database availability and scalability. It can be found here: https://www.oracle.com/database/technologies/clustering/rac.html

Example standard operation scheme for Cluster Web.

An example of a web cluster might include a load balancer, three NGINX web servers and PHP application servers, as well as a MySQL jail cluster.

The load balancer is responsible for distributing incoming web traffic between NGINX web servers. This ensures that none of the web servers are overloaded and that all clients receive a fast and reliable response.

NGINX web servers handle incoming HTTP requests from clients and provide the appropriate responses. They also use the PHP application server to execute application code and generate the dynamic content of web pages.

The MySQL jail cluster, on the other hand, is responsible for maintaining application data. It consists of a group of MySQL servers that work together to provide a copy of data across multiple servers and ensure data availability should one of the servers fail.

In summary, the web cluster works in a coordinated way to deliver reliable and scalable web services to clients. The load balancer distributes traffic between NGINX web servers, which use the PHP application server to execute application code and generate dynamic web page content. The MySQL jail cluster, on the other hand, takes care of maintaining application data.