How to Backup a Virtual Machine on KVM?

In this article, we will show some options for backing up virtual machines on a KVM hypervisor, as well as recovery scenarios. I would like to note that there are no convenient backup tools for KVM, and every administrator uses their own methods and scripts.  There are two backup scenarios in KVM: when a VM is stopped (the easiest one, but rarely used) and without stopping the virtual machine.

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VirtualBox: Cannot Register the Hard Disk Already Exists

When trying to connect a copied or moved disk image file (*.VHD/*.VDI) of an Oracle VirtualBox virtual machine, you will receive an error:

VirtualBox - Error
Failed to open the hard disk image file FilePath.vhd.
Cannot register the hard disk FilePath.vhd <GUID> because a hard disk DifferentFilePath.vhd with UUID <GUID> already exists.
Result Code: E_INVALIDARG (0x80070057)
Component: VirtualBoxWrap
Interface:IVirtualBox {GUID}
Callee RC: VBOX_E_OBJECT_NOT_FOUND (0x80BB0001)

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Postfix: Using Microsoft 365 as SMTP Relay

Postfix mail server is available in almost all Linux distributions. You can use it as a simple relay (smart host) to send email messages from your local network to user mailboxes and forward email queues to SMTP servers outside your organization. In this article, we’ll show you how to set up an SMTP relay for Microsoft 365 (Office 365, Exchange Online) with postfix on Linux (using Ubuntu/Debian as an example).

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Using Google Chrome Remote Desktop to Access Your Computers

Recently I have been favorably impressed with Chrome Remote Desktop features which allow to support remote users/friends/family members and access work computers remotely. I have easily configured access to my home computer from my office network. All you need is to install the Google Chrome browser on both devices, a Google account, and the chromoting service. Most popular are supported for remote connection: Windows, Linux, macOS, Android, and iOS.

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Domain Controller Crashes on Boot with Stop Code 0xc00002e2

After an emergency shutdown of a physical server with an Active Directory domain controller role, the BSOD with an error stop code 0x00002e2 appears on boot. The error points out that the Active Directory database (NTDS.DIT) is damaged. In this article, we will figure out how to fix the ntds.dit file and start a domain controller (in our case, it is a server running Windows Server 2019).

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Windows: Monitoring Logs and Text File Changes in Real Time

If a Windows service or application writes logs not to the Event Viewer (.evt and .evtx files), but to plain text log files, you sometimes need to display and monitor new events in real-time.

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Backing Up Docker Volumes

To automate docker partition backups, I recommend using Docker-volume-backup image (https://github.com/offen/docker-volume-backup). This lightweight image (about 15 MB) allows you to connect to any volume in docker and backup files to a local directory, S3-compatible storage (AWS S3, MimIO, Ceph, etc.), or send save it to a remote device via WebDAV or SSH.

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