Why is a rolling update beneficial in maintaining service availability?

A rolling update is beneficial in maintaining service availability because it allows for upgrading servers one at a time without incurring downtime. This approach ensures that while one server is being updated, the others can continue to handle requests and serve users. This helps in maintaining a seamless user experience and avoids the disruption that could occur if all servers were taken offline simultaneously.

In contrast, restarting all servers at once could lead to complete service interruption, which would not be ideal for maintaining availability. Changing network settings is unrelated to the update process itself and could introduce complications. Providing a backup of all service data is important for data protection but does not directly contribute to maintaining service availability during an update. Thus, the method of performing updates in a rolling fashion effectively strikes a balance between keeping the system current and ensuring continuous service access.