virt-utils

Installation (Ubuntu 24.04)

• Install packaage

sudo apt install -y qemu-kvm libvirt-daemon-system libvirt-clients bridge-utils virtinst libguestfs-tools libosinfo-bin

• Add user into libvirt and kvm group.

sudo usermod -aG kvm,libvirt $USER
newgrp libvirt

netplan

• Edit /etc/netplan# cat 50-cloud-init.yaml

network:
    ethernets:
        eno1:
          dhcp4: no
    bridges:
        br0:
            interfaces: [eno1]
            addresses:
            - 172.17.4.253/23
            nameservers:
                addresses:
                - 8.8.8.8
                search: []
            routes:
            -   to: default
                via: 172.17.5.254
    version: 2

net-start

• create kvm-hostbridge.xml

<network>
  <name>hostbridge</name>
  <forward mode="bridge"/>
  <bridge name="br0"/>
</network>

• enable the network

virsh net-define kvm-hostbridge.xml
virsh net-start hostbridge
virsh net-autostart hostbridge

• enable ipforward

sudo iptables -A FORWARD -p all -i br0 -j ACCEPT

Reference

https://www.cherryservers.com/blog/install-kvm-ubuntu
https://www.dzombak.com/blog/2024/02/Setting-up-KVM-virtual-machines-using-a-bridged-network.html

Libvirt

Scripts to launch VM by using virsh

QEMU

Scripts to launch VM by using qemu-system-*

Customized VM Images

• change root password to 'root' (OS=ubuntu img-reset-password.sh image password)
• added Garfield and Orchimaru into hosts
• added user 'ubuntu'
• added 'ubuntu' into sudo
• support authorized_keys upload (OS=ubuntu img-upload-authorized-keys.sh image user_id)
• change disk size to 8GB (img-resize.sh image 8G)
• shrik file size
• install JDK
• added "net.ifnames=0" to /etc/default/grub and line GRUB_CMDLINE_LINUX and update-grub

Grub Setting

/etc/default/grub

--- GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
+++ GRUB_CMDLINE_LINUX_DEFAULT="console=tty1 console=ttyS0"

/boot/grub/grub.cfg

root@worker-1:/boot/grub# blkid
/dev/vda1: LABEL="cloudimg-rootfs" UUID="cc3a13c5-c36c-4021-af14-6ff186f0b4bd" TYPE="ext4" 

root@worker-1:/boot/grub# vi grub.cfg
if [ x$feature_platform_search_hint = xy ]; then
  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt1 --hint-effi=hd0,gpt1 --hint-baremetal=ahci0,gpt1 cc3a13c5-c36c-4021-af14-6ff186f0b4bd
else
  search --no-floppy --fs-uuid --set=root cc3a13c5-c36c-4021-af14-6ff1866f0b4bd  
fi
linux   /boot/vmlinuz-4.15.0-65-generic root=UUID=cc3a13c5-c36c-4021-af14-6ff186f0b4bd ro  console=tty1 console=ttyS0

Useful Commands

List inactive VM

virsh list --inactive

Reference

• extlinux for Debian OpenStack Image. http://shallowsky.com/linux/extlinux.html
• virt-rescue for MBR or Image broken. http://libguestfs.org/virt-rescue.1.html Use root account for virt-rescue

Git Access by using SSH

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/github_rsa
git clone [email protected]:cplus66/virt-utils.git

or

ssh-agent bash
ssh-add ~/.ssh/github_rsa

VM Network Configuration

Yocto Systemd Networkd

cat << EOF > 20-wired.network
# enp0s3.network
[Match]
Name=enp0s3

[Network]
#DHCP=ipv4
VLAN=vlan1001
EOF
cat << EOF > vlan1001.netdev
[NetDev]
Name=vlan1001
Kind=vlan

[VLAN]
Id=1001
EOF
cat << EOF > vlan1001.network
[Match]
Name=vlan1001

[Network]
DHCP=no
Address=192.168.10.42/24
Gateway=192.168.10.1
DNS=8.8.8.8

LinkLocalAddressing=no
EOF

Create a New VM Host

• hostnamectl set-hostname $HOSTNAME
• edit /etc/hosts
• edit /etc/network/interfaces

Resize VM Disk Size

Ubuntu 20.04

• blkid
• parted
• fdisk
• resize2fs
• edit /etc/default/grub.d/40-force-partuuid.cfg
• update-grub

Ubuntu 18.04

• parted
• fdisk
• resize2fs