Hello everyone! I have encountered a complex task of implementing fault tolerance to ensure that if one of the channels or servers fails, the domain will still resolve to a live IP. It is important to note that using AA records to randomly alternate between IPs in the zone for the domain is not a viable solution since it can result in packets going nowhere in the event of communication loss with one of the servers.

Does anyone have any solutions to this problem with minimal labor and technological costs? Load balancing or duplication of two interchangeable machines in case of failure may be an option.
I have heard that it can be implemented on a cluster with OBSD or pFSense, but I am open to other suggestions as well.

When a webserver reaches 100% load, it usually cannot serve all user requests and results in less "effective uptime" than 100%, leading to dissatisfied users. However, starting a project with uncertain attendance and requirements can result in wasted resources on scalability.

Competitors who quickly adapt their projects may have already taken over the market, leaving little room for those who spent time and money on scalability. Furthermore, providing scalability may still result in new requirements that require further changes. Overall, despite efforts to prepare for scalability, adaptation is still necessary to succeed.

There are several approaches you can consider to implement fault tolerance and ensure high availability for your domain. Here are a few suggestions:

1. Load Balancing: Implementing a load balancing solution can distribute the traffic across multiple servers, providing redundancy and fault tolerance. You can use hardware load balancers or software-based solutions like HAProxy or Nginx.

2. Redundancy and Failover: Set up redundant servers that can takeover if the primary server fails. This can be achieved through active-passive clustering or using technologies like Pacemaker and Corosync.

3. DNS Failover: Utilize a DNS failover service that monitors the health of your servers and automatically routes traffic to a backup IP address in case of failure. These services periodically ping your servers to ensure they are live and functioning properly.

4. Cloud Provider Solutions: Consider leveraging cloud provider services like Amazon Route 53 or Azure Traffic Manager that provide built-in solutions for load balancing and failover.

5. Network-level Redundancy: Implement network-level redundancy by using technologies like VRRP (Virtual Router Redundancy Protocol) or HSRP (Hot Standby Router Protocol) to ensure continuous connectivity even if one of the routers or gateways fails.