The Power Management feature in an instance allows you to control its power state. It provides several options for managing the instance, similar to what you would find in physical servers or computers. Let's break down each option:
Power Off
This option will gracefully shut down the instance. When you choose to power off, the operating system inside the instance will go through a proper shutdown process, saving any necessary data, closing applications, and then shutting down completely.
- Use Case: Use this when you want to safely turn off the instance without losing any unsaved work, or before performing certain maintenance activities (like modifying instance settings).
Note: Once powered off, the instance is no longer consuming CPU resources, though you might still be charged for storage (disk space).
Power Reset
This option resets or restarts the instance, similar to pressing the "reset" button on a physical machine. The instance shuts down abruptly and immediately restarts. It does not go through a graceful shutdown process. Any unsaved work will be lost.
- Use Case: Use this when the instance becomes unresponsive or needs a quick restart, and you don't need to worry about data loss (for example, if it's a testing environment or a non-production machine).
Warning: Since it's an abrupt reset, there’s a risk of data corruption if any critical tasks were in progress.
Power Cycle
This performs a full power cycle by turning off the instance and then powering it back on. This is like manually turning off a physical server and turning it back on again after a few seconds. It ensures that all resources are completely cleared and reinitialized upon reboot.
- Use Case: Power cycling is often used for instances experiencing persistent performance issues or in cases where a complete reboot of the environment is required (e.g., for applying certain system updates).
While both 'Power Cycle' and 'Power Reset' restart the system, power cycling ensures the system is fully powered down before restarting, making it a "hard reboot."
IMPORTANT: The power management feature is not available while your virtual machine is in rescue mode. To utilize power management, please exit rescue mode.