Installation⚓
- Install required packages
apt-get install qemu-kvm libvirt-bin bridge-utils virtinst
- Setup /etc/network/interfaces
iface eth0 inet manual auto br0 iface br0 inet static bridge_interfaces eth0 bridge_stp off bridge_maxwait 5 .. address, netmask, etc.
Try to put br0 interface up or reboot
brctl addbr br0
Deploy instance⚓
Now you have more options
- deploy from custom image
- deploy clean Ubuntu using ubuntu-vm-builder
Ubuntu VM builder⚓
Attention!
Untested
apt-get install ubuntu-vm-builder
ubuntu-vm-builder kvm trusty --rootsize=10000 --domain cfg01 --dest cfg01
--hostname cfg01 --arch amd64 --mem 4096 --ip 172.19.5.30 --mask 255.255.255.0
--net 172.19.0.0 --gw 172.19.5.0 --dns 172.19.0.1 --libvirt qemu:///system
--addpkg openssh-server --addpkg acpid --addpkg vim-nox --components
"main,universe"
Boot from image⚓
apt-get install virtinst
- Get image and prepare image for guest (you can use overlay image instead)
cd /var/lib/libvirt/images wget http://apt.cloudlab.cz/images/ubuntu-14-04-x64-1437659147.qcow2 cp ubuntu-14-04-x64-1437659147.qcow2 cfg01.qcow2- Install guest
virt-install --name cfg01 \ --ram 4096 --vcpus=2 \ --accelerate --network bridge:br0 \ --disk path=/var/lib/libvirt/images/cfg01.qcow2,bus=virtio,cache=none \ --boot hd --vnc --noreboot --autostart
Using overlay image⚓
To save disk space, you can use overlay image instead of copying original image for each instance.
qemu-img create -f qcow2 -b ubuntu-14-04-x64-1437659147.qcow2 cfg01.ovl
Then simply use *.ovl for --disk parameter of virt-install command.
Attention!
Don’t ever touch original image
Cloud-init configuration⚓
To use cloud-init with libvirt, you need to provide meta-data and user-data somehow. There are multiple data sources that cloud-init expects, the simplest way is probably to generate configuration iso and attach it to instance cdrom.
- Install dependencies
apt-get install genisoimage curl -q https://raw.githubusercontent.com/larsks/virt-utils/master/create-config-drive | sed s,/bin/sh,/bin/bash,g > create-config-drive chmod +x create-config-drive- Prepare userdata file, eg. userdata.sh
#!/bin/bash sed -i '/iface\ eth0\ inet\ dhcp/d' /etc/network/interfaces cat << EOF >> /etc/network/interfaces iface eth0 inet static address 172.19.5.101 netmask 255.255.255.0 gateway 172.19.5.254 dns-nameservers 172.19.0.1 EOF ifdown eth0; ifup eth0 echo "id: test1.int.cloudlab.cz" >> /etc/salt/minion.d/minion.conf echo "master: 172.19.5.30" >> /etc/salt/minion.d/minion.conf service salt-minion restart salt-call state.highstate
- Generate configuration iso image
./create-config-drive -k ~/.ssh/id_rsa.pub -u userdata.sh -h test1 test1-config.iso
- Finally you can create domain
virt-install --name test1 \ --ram 4096 --vcpus=2 \ --accelerate --network bridge:br0 \ --disk path=/var/lib/libvirt/images/test1.qcow2,bus=virtio,cache=none --disk path=test1-config.iso,device=cdrom \ --boot hd --vnc --noreboot --autostart \
Manage instance⚓
- List instances
virsh list --all
- Stop instance gracefuly
virsh shutdown cfg01
- Stop instance by force in case it’s hanged
virsh destroy cfg01
- Delete instance
virsh undefine cfg01
Resize disk⚓
Attention!
Shut down instance first, this is important
You can resize both overlay image or normal image. But don’t ever resize image that is source for overlay images.
qemu-img resize cfg01.ovl +10G
On reboot, cloud-init should automatically grow root filesystem.
Extend memory⚓
First you need to redefine max memory for guest:
virsh setmaxmem cfg01 16G --config
After that you need to destroy domain and start it again.
Finally you can set memory onlin with following command:
virsh setmem cfg01 16G --config --live
Parameter --config will update domain XML so changes will preserve boot.