What feature is strongly recommended to enable by default on every Azure virtual machine server to help resolve common issues?

Enabling boot diagnostics by default on every Azure virtual machine server is strongly recommended as it provides critical insights into the state of the virtual machine during the boot process. This feature allows administrators to capture and view the console output and screenshots of the VM, which can be invaluable for troubleshooting issues that occur during boot-up or initialization.

When a virtual machine fails to start, boot diagnostics can help identify the specific problem by providing a detailed log of the boot sequence and error messages. By having this feature enabled, it becomes easier to troubleshoot configurations, identify hardware issues, and ensure that the VM is properly configured. This proactive measure can significantly reduce downtime and streamline the troubleshooting process.

Other features like Resource Manager, instance metadata, and Azure Security Center have their own importance, but they do not provide the same direct insight into boot issues as boot diagnostics. Resource Manager is focused on resource management and organization, instance metadata offers information about the VM instance itself, and Azure Security Center is designed to enhance the security posture rather than directly address boot problems. Thus, boot diagnostics stands out as a critical feature in diagnosing and resolving common issues right from the start of a VM's lifecycle.