dmidecode -s system-product-name

Virtualization technology

VMware Workstation

root@router:~# dmidecode -s system-product-name
VMware Virtual Platform

VirtualBox

root@router:~# dmidecode -s system-product-name
VirtualBox

QEMU and KVM

root@router:~# dmidecode -s system-product-name
KVM

QEMU (emulation)

root@router:~# dmidecode -s system-product-name
Bochs

Microsoft Virtual PC

root@router:~# dmidecode | egrep -i 'manufacturer|product'
Manufacturer: Microsoft Corporation
Product Name: Virtual Machine

Virtuozzo

root@router:~# dmidecode
/dev/mem: Permission denied

en

root@router:~# dmidecode | grep -i domU
Product Name: HVM domU

/dev/disk/by-id

If you do not have permission to run dmidecode, you can use: ls -1 /dev/disk/by-id/

Virtualization technology: QEMU

[root@host-7-129 ~]# ls -1 /dev/disk/by-id/
ata-QEMU_DVD-ROM_QM00003
ata-QEMU_HARDDISK_QM00001
ata-QEMU_HARDDISK_QM00001-part1
ata-QEMU_HARDDISK_QM00002
ata-QEMU_HARDDISK_QM00002-part1
scsi-SATA_QEMU_HARDDISK_QM00001
scsi-SATA_QEMU_HARDDISK_QM00001-part1
scsi-SATA_QEMU_HARDDISK_QM00002
scsi-SATA_QEMU_HARDDISK_QM00002-part1