Introduction
QEMU (Quick Emulator) is a powerful open-source virtualization tool that allows you to run virtual machines on your computer.
What we will do
- setup Ubuntu desktop VM, test it with SSH access and netcat
- setup Ubuntu live-server VM, test it with SSH access as well
I am using macOS (Intel-based) but the procoess is same for all linux with minor variations
Step 1: Installation (Desktop)
i. install QEMU
brew install qemu
cd /usr/local/opt/qemu/bin
ls
brew install qemu
cd /usr/local/opt/qemu/bin
ls
we navigate to the QEMU binaries directory and see various qemu-system-* binaries. Since we’re on an x86_64 architecture (Intel Mac), we’ll use qemu-system-x86_64.
ii. Download Ubuntu ISO images
wget https://releases.ubuntu.com/focal/ubuntu-20.04.6-desktop-amd64.iso
wget https://releases.ubuntu.com/focal/ubuntu-20.04.6-live-server-amd64.iso
wget https://releases.ubuntu.com/focal/ubuntu-20.04.6-desktop-amd64.iso
wget https://releases.ubuntu.com/focal/ubuntu-20.04.6-live-server-amd64.iso
Personally, I prefer to use live-server b/c it is lightweight and fast but gui has it’s own benefits so I just keep it around just in case !
iii. Create a Virtual Disk Image
Create a 60GB virtual disk that will serve as your VM’s hard drive:
qemu-img create -f qcow2 ubuntu2004.qcow2 60G
qemu-img create -f qcow2 ubuntu2004.qcow2 60G
qemu-img create: QEMU’s disk image creation tool-f qcow2: Specifies the qcow2 format (QEMU Copy-On-Write version 2)ubuntu2004.qcow2: The filename for your virtual disk60G: The maximum size of the disk (it starts small and grows as needed)
The qcow2 format is space-efficient because it only uses disk space for data actually written to it, not the entire 60GB upfront.
iv. Install Ubuntu Desktop
qemu-system-x86_64 \
-accel tcg \
-smp 2 \
-m 4G \
-boot d \
-vga std \
-cdrom ubuntu-20.04.6-desktop-amd64.iso \
-drive file=ubuntu2004.qcow2,if=virtioqemu-system-x86_64 \
-accel tcg \
-smp 2 \
-m 4G \
-boot d \
-vga std \
-cdrom ubuntu-20.04.6-desktop-amd64.iso \
-drive file=ubuntu2004.qcow2,if=virtio-accel tcg: Use TCG (Tiny Code Generator) for software-based CPU emulation-smp 2: Allocate 2 CPU cores to the VM-m 4G: Allocate 4GB of RAM-boot d: Boot from CD-ROM (the ‘d’ stands for CD-ROM drive)-vga std: Use standard VGA graphics (most compatible)-cdrom ubuntu-20.04.6-desktop-amd64.iso: Mount the Ubuntu ISO as a CD-ROM-drive file=ubuntu2004.qcow2,if=virtio: Attach our virtual disk with VirtIO interface for better performance
Why Not Use host machine Hardware Acceleration?
using
-accel hvf(Apple’s Hypervisor Framework) or-cpu hostgives better performance. but it don’t work for ubuntu desktop. This passthrough used to work but now it is not working anymore.I was able to make hvf work work for ubuntu live-server, we will see later in article.
Now go through with the normal setup instructions
Step 2: Testing
i. Boot Your Installed Ubuntu VM
Now that Ubuntu is installed, we can boot from the virtual disk without the ISO.
We’ll also add networking and port forwarding in order to test it using netcat and ssh
qemu-system-x86_64 \
-accel tcg \
-smp 2 \
-m 4G \
-vga std \
-usb \
-device usb-tablet \
-device virtio-net,netdev=vmnic \
-netdev user,id=vmnic,hostfwd=tcp::2222-:22,hostfwd=tcp::9999-:9999 \
-audiodev coreaudio,id=coreaudio \
-device ich9-intel-hda -device hda-output,audiodev=coreaudio \
-drive file=ubuntu2004.qcow2,if=virtioqemu-system-x86_64 \
-accel tcg \
-smp 2 \
-m 4G \
-vga std \
-usb \
-device usb-tablet \
-device virtio-net,netdev=vmnic \
-netdev user,id=vmnic,hostfwd=tcp::2222-:22,hostfwd=tcp::9999-:9999 \
-audiodev coreaudio,id=coreaudio \
-device ich9-intel-hda -device hda-output,audiodev=coreaudio \
-drive file=ubuntu2004.qcow2,if=virtio-usband-device usb-tablet: Enable USB and add a tablet device for better mouse integration-device virtio-net,netdev=vmnic: Add a virtual network card-netdev user,id=vmnic,hostfwd=tcp::2222-:22,hostfwd=tcp::9999-:9999: Configure user-mode networking with port forwardinghostfwd=tcp::2222-:22: Forward Mac’s port 2222 to VM’s port 22 (SSH)hostfwd=tcp::9999-:9999: Forward Mac’s port 9999 to VM’s port 9999 (for testing)
-audiodev coreaudio,id=coreaudio: Enable audio using macOS’s Core Audio-device ich9-intel-hda -device hda-output,audiodev=coreaudio: Add Intel HDA audio device
ii. Connection with Netcat
In your Ubuntu VM terminal:
sudo apt update
sudo apt install netcat -y
nc -l -p 9999 # starts netcat listening on port 9999.sudo apt update
sudo apt install netcat -y
nc -l -p 9999 # starts netcat listening on port 9999.On your host terminal:
nc localhost 9999
nc localhost 9999Now type a message in either terminal and press Enter. The message should appear in the other terminal! This confirms that port forwarding is working.
iii. Connection with SSH
Install OpenSSH Server in Ubuntu VM:
sudo apt update
sudo apt install openssh-server -y
sudo systemctl start ssh
sudo systemctl enable ssh
sudo systemctl status ssh # verify its started and workingsudo apt update
sudo apt install openssh-server -y
sudo systemctl start ssh
sudo systemctl enable ssh
sudo systemctl status ssh # verify its started and workingOn your host terminal:
ssh -p 2222 taimourz@localhost # use your own username
ssh -p 2222 taimourz@localhost # use your own username
iv. Demo (SSh and netcat)
Step 3: Installation (Server)
i. why we need it
First of all it’s really fast. mac does not give you the control you need.
The whole process is same as desktop with a few changes
ii. create virtual image
qemu-img create -f qcow2 ubuntu-server.qcow2 60Gqemu-img create -f qcow2 ubuntu-server.qcow2 60Giii install into virtual disc
qemu-system-x86_64 \
-accel tcg \
-smp 2 \
-m 4G \
-boot d \
-cdrom ubuntu-22.04.5-live-server-amd64.iso \
-drive file=ubuntu-server.qcow,if=virtio,format=qcow2qemu-system-x86_64 \
-accel tcg \
-smp 2 \
-m 4G \
-boot d \
-cdrom ubuntu-22.04.5-live-server-amd64.iso \
-drive file=ubuntu-server.qcow,if=virtio,format=qcow2iv. update grub
first boot in normal gui mode otherwise so we can make changes in the grub file so next time we can run it from the terminal
qemu-system-x86_64 \
-accel tcg \
-smp 2 \
-m 4G \
-drive file=ubuntu-server.qcow2,if=virtio,format=qcow2 \
-device virtio-net,netdev=vmnic \
-netdev user,id=vmnic,hostfwd=tcp::2222-:22
qemu-system-x86_64 \
-accel tcg \
-smp 2 \
-m 4G \
-drive file=ubuntu-server.qcow2,if=virtio,format=qcow2 \
-device virtio-net,netdev=vmnic \
-netdev user,id=vmnic,hostfwd=tcp::2222-:22
Once you have logged in, then you would need to update the grub file /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,115200n8"
GRUB_CMDLINE_LINUX="console=tty0 console=ttyS0,115200n8"
GRUB_TERMINAL="serial console"
GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,115200n8"
GRUB_CMDLINE_LINUX="console=tty0 console=ttyS0,115200n8"
GRUB_TERMINAL="serial console"
GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"then we run these commands
sudo update-grub
sudo systemctl enable serial-getty@ttyS0.service
sudo systemctl start serial-getty@ttyS0.service
sudo shutdown -h now
sudo update-grub
sudo systemctl enable serial-getty@ttyS0.service
sudo systemctl start serial-getty@ttyS0.service
sudo shutdown -h now
v. boot directly from terminal
I was able to get the hvf running in the server. This will run blazingly fast.
qemu-system-x86_64 -m 4G -hda ubuntu-server.qcow2 -accel hvf \
-net nic -net user,hostfwd=tcp::2222-:22,hostfwd=tcp::9999-:9999 \
-serial mon:stdio \
-nographicqemu-system-x86_64 -m 4G -hda ubuntu-server.qcow2 -accel hvf \
-net nic -net user,hostfwd=tcp::2222-:22,hostfwd=tcp::9999-:9999 \
-serial mon:stdio \
-nographicvi. Testing with SSH
Create a new user from guest VM:
sudo adduser taimour
id taimour # verify
uid=1001(taimour) gid=1001(taimour) groups=1001(taimour)
sudo adduser taimour
id taimour # verify
uid=1001(taimour) gid=1001(taimour) groups=1001(taimour)The do ssh from host machine
ssh -p 2222 taimour@localhost
ssh -p 2222 taimour@localhost