KVM Lab Setup

Qemu stuff I did before settingup KVM

sudo apt install qemu sudo apt install qemu-utils sudo apt install qemu-system-x86

qemu-img create ubuntu.img 20G

qemu-system-x86_64 -hda ubuntu.img -boot d -cdrom /home/user1/Downloads/rhel-8.4-x86_64-dvd.iso -m 1000 qemu-system-x86_64 -hda ubuntu.img -boot d -cdrom /home/user1/Downloads/rhel-8.4-x86_64-dvd.iso -m 1000

sudo apt install libvirt-clients virsh

KVM

0 # cpu doesn’t support hardware virtualization 1 or more # cpu does support hardware virtualization ( still needs to be enabled in bios )

Check if it is actually enabled ( Xen kernel only ):

cat /sys/hypervisor/properties/capabilities

Also check if it is enabled with this: sudo apt update sudo apt install cpu-checker # probably already there kvm-ok

sudo apt-get install qemu-kvm libvirt-daemon-system libvirt-clients bridge-utils virtinst sudo apt-get install virt-manager

sudo systemctl is-active libvirtd

sudo usermod -aG libvirt $USER sudo usermod -aG kvm $USER

virsh list –all

brctl show

“Virtual Machine Manager” - this is virt-manager

Serial Console:

virsh ttyconsole my_vm more info: https://help.ubuntu.com/community/KVM/Access

Networking: https://help.ubuntu.com/community/KVM/Networking#Bridged_Networking

https://levelup.gitconnected.com/how-to-setup-bridge-networking-with-kvm-on-ubuntu-20-04-9c560b3e3991 <======================

sudo brctl addbr br0

If you have any issues:

if any error - log out and back in ( from terminal or also from desktop especially if launching virt-manager from a menu )

- check if you can write to this
   sudo ls -la /var/run/libvirt/libvirt-sock

If you have problems creating a VM:

sudo chown root:libvirtd /dev/kvm

relogin or restart kernel modules

rmmod kvm modprobe -a kvm

virsh –connect qemu:///system create alice.xml # might be needed if you have another hypervisor like VirtualBox

https://www.xmodulo.com/use-kvm-command-line-debian-ubuntu.html

qemu-img create -f qcow2 alice.img 10G ls -l Downloads/ubuntu-20.04.3-live-server-amd64.iso vi alice.xml virsh create alice.xml virsh start alice virsh list sudo brctl addbr br0 sudo brctl show

sudo netstat -nap | egrep ‘(kvm|qemu)’ # find vnc port virsh destroy alice virsh shutdown alice virsh suspend alice virsh resume alice virsh console alice virsh autostart alice virsh dominfo alice virsh edit alice virsh undefine alice # actually delete vm ( shutdown before or after )

virsh domrename vm1 template # rename a VM

virsh # basically run a virsh shell

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disable netfilter on bridges

/etc/sysctl.d/bridge.conf

net.bridge.bridge-nf-call-ip6tables=0 net.bridge.bridge-nf-call-iptables=0 net.bridge.bridge-nf-call-arptables=0

/etc/udev/rules.d/99-bridge.rules

ACTION==”add”, SUBSYSTEM==”module”, KERNEL==”br_netfilter”, \ RUN+=”/sbin/sysctl -p /etc/sysctl.d/bridge.conf”

remove default kvm interfaces:

virsh net-destroy default virsh net-undefine default

remove with these commands if the interfaces haven’t been removed:

ip link delete virbr0 type brigde ip link delete virbr0-nic.

/etc/netplan/00-installer-config.yaml

network: ethernets: enp0s7: dhcp4: false dhcp6: false bridges: br0: interfaces: [ enp0s7 ] addresses: [192.168.0.104/24] gateway4: 192.168.0.1 mtu: 1500 nameservers: addresses: [8.8.8.8,8.8.4.4] parameters: stp: true forward-delay: 4 dhcp4: no dhcp6: no version: 2

network: ethernets: eno2: dhcp4: false dhcp6: false bridges: br0: interfaces: [ eno2 ] addresses: [192.168.3.22/24] gateway4: 192.168.3.1 mtu: 1500 nameservers: addresses: [8.8.8.8,8.8.4.4] parameters: stp: true forward-delay: 4 dhcp4: no dhcp6: no version: 2

Above, static config from enp0s7 is moved to br0

sudo netplan apply

host-bridge.xml

virsh net-define host-bridge.xml virsh net-start host-bridge virsh net-autostart host-bridge

virsh net-list –all

Change interface for dhcp server:

sudo vi /etc/default/isc-dhcp-server

INTERFACESv4=”br0”

example: virt-install –name vm1 –ram=8192 –disk size=10 –vcpus 1 –os-type linux –os-variant ubuntu20.04 –graphics none –location ‘http://archive.ubuntu.com/ubuntu/dists/focal/main/installer-amd64/’ –extra-args “console=tty0 console=ttyS0,115200n8” working: virt-install –name vm1 –ram=8192 –disk size=10 –vcpus 1 –os-type linux –os-variant ubuntu20.04 –cdrom /home/user1/Downloads/ubuntu-20.04.3-live-server-amd64.iso

• or just create VM from GUI

virsh domifaddr vm1 # get ip address ssh-copy-id rkamradt@192.168.122.95 # use ip address from previous step

virsh domifaddr node1

make sure your guest VM requests a DHCP lease by MAC and not hostid

/etc/netplan/00-installer-config.yaml

This is the network config written by ‘subiquity’

network: ethernets: enp1s0: dhcp4: true dhcp-identifier: mac version: 2

Cloning VMs

virt-clone –original vm1 –name vm2 –auto-clone virt-clone –original vm1 –name vm3 –auto-clone

Create 10 clones:

for i in 0 1 2 3 4 5 6 7 8 9; do virt-clone –original template –name vm$i –auto-clone; done

Get MAC address:

virsh domiflist vm1 virsh domiflist vm5|grep -i bridge| awk ‘{ print $5 }’ for i in virsh list --all| tail -n +3| head -n -1 | awk '{print $2}'; do virsh domiflist $i|grep -i bridge| awk ‘{ print $5 }’; done ## list all MACs

Start all VMs:

for i in virsh list --all| tail -n +3| head -n -1 | awk '{print $2}'; do virsh start $i; done

Stop all VMs:

for i in virsh list --all| tail -n +3| head -n -1 | awk '{print $2}'; do virsh stop $i; done

host test1 { hardware ethernet 08:00:27:85:AE:C9; fixed-address 192.168.3.150; }

Map IPs to MACs in DHCP:

Almost except that 10 is wrong, need better counting. Use IP pools in Python: ( also maybe exclude the template and create a pool for names )

Don’t really need this once it is added to the template:

OR

ssh-copy-id -i ~/.ssh/id_rsa.pub user1@host

for i in 51 52 53 54 55 56 57 58 59 60; do ssh-copy-id -i ~/.ssh/id_rsa.pub user1@192.168.3.1$i; done