Terminal command to find out if a server is virtual or physical

command linevirtual machine

I am looking for a terminal command which doesn't require the executing user to be in the sudoers group and also to be universal and not requiring to install additional packages. So far I have found that if the system has systemd installed then I can use:

$ hostnamectl status
   Static hostname: mint
         Icon name: computer-laptop
           Chassis: laptop
        Machine ID: bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
           Boot ID: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
  Operating System: Linux Mint LMDE
            Kernel: Linux 3.16.0-6-amd64

and under Icon name and Chassis I can see if it is VM or physical machine. But I was wondering if I can use lscpu, especially since it is more universal method than hostnamectl and it doesn't require systemd. My theory is that if the CPU has only one thread per core and also not listed minimum and maximum CPU frequency this should be an indication that the server is indeed virtualized.

$ lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                8
On-line CPU(s) list:   0-7
Thread(s) per core:    2
Core(s) per socket:    4
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 60
Model name:            Intel(R) Core(TM) i7-4710HQ CPU @ 2.50GHz
Stepping:              3
CPU MHz:               2500.488
CPU max MHz:           3500.0000
CPU min MHz:           800.0000
BogoMIPS:              4988.18
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              6144K
NUMA node0 CPU(s):     0-7

I know that the if a CPU has only one thread per core doesn't necessarily means that it is VM for sure, but then all modern CPUs should have 2 threads per core and in addition I can also take into account the lack/presence of minimum and maximum CPU frequency in the lscpu output.

Best Answer

Under given conditions:

terminal command which doesn't require the executing user to be in the sudoers group and also to be universal and not requiring to install additional packages.

the obvious simplest method for unmodified VMs, which owners intentionally haven't tried to hide fact the OS is VM, is

cat /sys/class/dmi/id/product_name

More possibilities:

Outside of the given by OP author conditions there are more complicated approaches like this one: Where am I? Operating System and Virtualization Identification Without System Calls

Related Solutions

Terminal-based (non GUI) virtual-computer program

In qemu/kvm, you only get a GUI if you attach a video card to your VM and if you don't expose it as SPICE/VNC.

For instance, you can do (zsh syntax, with grub2):

grub-mkimage -O i386-pc -c =(print -l serial 'terminal_input serial' \
 'terminal_output serial' 
 ) -o grub.img configfile biosdisk part_msdos part_gpt ext2 \
   linux test serial halt minicmd cat

And start your VM with:

kvm -kernel grub.img -hda yourdisk.img -nographic

From the grub prompt, load the kernel from the disk passing console=ttyS0... option or equivalent on the system you're booting to have the console on serial. Remember to add a getty on the serial line as well.

Assuming you're running Linux in the VM, you can then update its grub config to display on serial and boot a kernel with serial console, and then you can boot your image disk directly without that grub.img.

To access the qemu "monitor", type Ctrl-Ac (where you can add/remove devices...).

You can have the serial port as a unix domain or TCP socket, instead of stdio if you like as well. Same for the qemu "monitor" interface.

Now, provided you have the sgabios.bin firmware, and that your VM doesn't use graphics (just VGA BIOS text output), you can also just use the -curses option:

kvm -hda yourdisk -curses

The VGA console is then shown in your terminal. If you need to access the qemu monitor, press Alt-2.

Linux – Does two “virtual serial ports” exist in the virtual terminal implementation

The line discipline controls handling of special characters (like software flow control, or characters generating signals) over the "line" (i.e., electrical wire in early unix systems). There are several possible line disciplines, and the tty driver calls the line discipline responsible for that tty.

So it makes absolutely no sense to have a "virtual serial port" in front of the line discipline. Not in the first picture, and not in the second picture.

The line discipline in turn just calls other parts of the kernel (the serial port driver (USB, UART, whatever), or the emulator for a virtual console, etc.), and also gets called by the corresponding driver if characters arrive. So in some sense this is a "virtual switch" where you can hook in different components.

But there's no pair of serial port drivers that somehow simulate sending a byte as bits over the line with a certain speed, and then reassembling it from bits as a byte. Because that would be unnecessary slow, and doesn't give a functionality.

Nevertheless, you can set the baud rate, amount of stop bits etc. for all tty's. These parameters are just ignored by drivers that don't need them, like the virtual console.

Best Answer

Related Solutions

Terminal-based (non GUI) virtual-computer program

Linux – Does two “virtual serial ports” exist in the virtual terminal implementation

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