VM Files and Live State || Hypervisors VM || Virtualization

Summary

This video explains the structure and functionality of virtual machines (VMs), focusing on the distinction between the live state and persistent files. It details how a VM uses the host's resources like memory, CPU, and storage via a hypervisor. The video also covers how virtual machines access storage devices, such as virtual disks, and how configuration files, snapshots, and BIOS settings are crucial for the VM's operation. The live state refers to real-time actions on the host, while persistent files ensure data continuity even after a VM is shut down or restarted.

Takeaways

• 😀 The host machine provides the physical resources (memory, CPU, network, and storage) for virtual machines to operate.
• 😀 Virtual machines rely on the hypervisor to interact with the host's physical hardware.
• 😀 The 'live state' of a virtual machine includes memory, CPU processes, network usage, and storage traffic, all handled on the host.
• 😀 Virtual machines do not have dedicated physical hardware, including storage devices, and rely on external storage for data management.
• 😀 Virtual machine disk operations, such as reading and writing to the C drive, are redirected to physical storage devices, either local or networked.
• 😀 The virtual machine's storage files, including the virtual disk file, are often stored on shared storage that multiple virtual machines can access.
• 😀 When a virtual machine is powered off, configuration information (like memory, CPU, and disk size) is needed for rebooting the system.
• 😀 In addition to the virtual disk, other files essential for a virtual machine include configuration files, BIOS contents, and snapshot files.
• 😀 Virtual machines are comprised of two key elements: the live state (active memory, processes, and hardware use) and persistent storage (files like configuration, virtual disk, etc.).
• 😀 If the host fails, the live state of the virtual machine is lost (similar to unplugging a computer), but the stored files on the storage solution remain intact and can be used to reboot the VM.

Q & A

What does the host represent in the context of virtual machines?

The host refers to the physical hardware or server that runs the virtual machine (VM). It provides the VM with resources such as memory, CPU, network, and storage hardware through the hypervisor.

What is meant by the 'live state' of a virtual machine?

The 'live state' refers to the real-time activities occurring on the virtual machine, such as the programs running, the memory usage, CPU processing, network activity, and storage traffic. These processes are happening directly on the host system.

How does a virtual machine read from or write to a disk if it doesn't have its own dedicated physical hardware?

The virtual machine doesn't have dedicated physical hardware. Instead, its disk operations are redirected to a physical storage device through a storage adapter. This can be on local storage, a network storage device, or a shared storage solution.

What kind of files make up a virtual machine?

A virtual machine is composed of several types of files, including its virtual disk file, configuration files, BIOS file, and potentially snapshot files. These files are stored persistently on a physical storage device.

What happens to the virtual machine's live state if the host fails?

If the host fails, the live state of the virtual machine is lost. This includes the contents of memory and any ongoing processes. It's similar to unplugging a physical computer.

Where are the persistent files of a virtual machine stored?

The persistent files of a virtual machine, such as the virtual disk, configuration files, BIOS, and snapshot files, are stored on a physical storage device, which could be a local disk or a shared storage solution.

What type of storage solutions can be used for a virtual machine's persistent files?

The virtual machine's persistent files can be stored on various types of storage solutions, such as a local disk within the hypervisor, a fiber channel network, an Ethernet network, or other shared storage systems.

Why is it important to store virtual machine files on shared storage?

Storing virtual machine files on shared storage allows for better resource management, ensuring that multiple virtual machines can access their required files in a centralized location. It also enhances backup, recovery, and migration processes.

What happens when a virtual machine is shut down?

When a virtual machine is shut down, its live state is lost, but its configuration and persistent files remain. These files are necessary for booting up the VM again, including details about memory, CPU allocation, disk size, and more.

What kind of configuration information is stored for a virtual machine?

The configuration information for a virtual machine typically includes memory allocation, CPU settings, disk size, and other parameters required to boot and operate the virtual machine.