virt-inspector

virt-inspector is a command-line utility that is part of the libvirt suite, specifically designed to inspect virtual machine (VM) disk images. It allows administrators to view detailed information about the contents of virtual disk images, including filesystems, partitions, and other metadata without needing to boot the virtual machine.

This tool is particularly useful for system administrators and those working in virtualized environments, as it allows inspection of VM disk images offline. It can read disk image formats like qcow2, raw, and vmdk, among others.

Key Features of virt-inspector

• Inspect Virtual Machine Disk Images: Provides an easy way to inspect the contents of virtual machine disk images.

• View Partition Tables: Displays partition tables and information about individual partitions within the disk image.

• Filesystem Information: Shows detailed filesystem information including filesystem types and mount points.

• Metadata: Can provide metadata about virtual disks, including labels, UUIDs, and other useful attributes.

• Support for Multiple Disk Formats: Works with multiple virtual disk formats, including qcow2, raw, vmdk, and others.

• No Need for VM to Be Running: You can inspect the disk image offline, without requiring the virtual machine to be running.

Basic Syntax

virt-inspector [options] disk_image

• disk_image: The path to the virtual disk image you want to inspect.

Common Options

• -a, --add: Add one or more disk images to the inspection.

• -l, --long: Provides a long listing format with more detailed information (such as filesystem type and sizes).

• -m, --mount: Display the mount points for each filesystem in the image.

• -t, --type: Filter the output by a specific type of filesystem (e.g., ext4, xfs).

• -h, --help: Displays help information for the command.

Common Use Cases for virt-inspector

1. Inspect the Disk Image of a Virtual Machine

   To inspect a virtual machine disk image (e.g., /path/to/disk-image.qcow2), run:

   virt-inspector /path/to/disk-image.qcow2

   This will provide a summary of the disk image's contents, including partition table, filesystem types, and metadata.

2. Display Detailed Information about Filesystems

   To display detailed information about the filesystems in a virtual disk image, use the -l (long) option:

   virt-inspector -l /path/to/disk-image.qcow2

   This will show more detailed information, such as filesystem sizes and types.

3. Inspect Filesystem Types

   If you are interested in only certain types of filesystems (e.g., ext4), you can filter the output by filesystem type using the -t option:

   virt-inspector -t ext4 /path/to/disk-image.qcow2

   This will show only ext4 filesystems in the disk image.

4. View Partition Information

   If you want to see partition information (such as sizes and types of partitions), you can use the -l option:

   virt-inspector -l /path/to/disk-image.qcow2

   Output Example:

   /dev/sda1: ext4, size: 100G, mount point: /
   /dev/sda2: swap, size: 4G, mount point: none

5. Inspect a Running VM's Disk Image

   To inspect the disk image of a running virtual machine, you can specify the domain (VM) name:

   virt-inspector --domain vm_name

   This will show the disk image information for the specified running VM.

Example Output

• Example 1: Inspect a disk image (disk-image.qcow2):

  virt-inspector /path/to/disk-image.qcow2

  Output:

  Disk Image: /path/to/disk-image.qcow2
  Partition Table: GPT
  Filesystems:
  /dev/sda1: ext4, size: 100G, mount point: /
  /dev/sda2: swap, size: 4G, mount point: none

• Example 2: Detailed information about filesystems in a disk image:

  virt-inspector -l /path/to/disk-image.qcow2

  Output:

  Disk Image: /path/to/disk-image.qcow2
  Partition Table: GPT
  Filesystems:
  /dev/sda1: ext4, size: 100G, mount point: /
  /dev/sda2: swap, size: 4G, mount point: none

Why Use virt-inspector?

• Offline Inspection: It allows you to inspect a virtual disk image without having to run the virtual machine, making it useful for diagnostics or backups.

• Convenient Metadata: You can quickly obtain metadata, partition layouts, and filesystem types, which can be helpful when planning migrations or performing audits.

• Supports Multiple Formats: It can handle a variety of disk image formats (such as qcow2, raw, vmdk), which is useful in diverse virtualization environments.

• No Need for VM to Be Running: This tool doesn't require the VM to be running, which is helpful if the VM is down or if you need to inspect the disk image offline.

Conclusion

virt-inspector is an essential tool for inspecting virtual machine disk images, especially in virtualized environments managed with libvirt. It simplifies the process of querying detailed information about filesystems, partitions, and other metadata in a disk image without the need for the VM to be running. Whether you're performing backups, troubleshooting, or planning migrations, virt-inspector is a useful tool to quickly gather key details about virtual disks.