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workshop:libvirt_kvm [2010-06-23 16:06] mika mikas workshop notes |
workshop:libvirt_kvm [2015-09-16 12:41] |
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| - | ====== Workshop libVirt & KVM ====== | ||
| - | * by Christian Pointner | ||
| - | * workshop notes by Michael Prokop | ||
| - | |||
| - | ===== Ressources ===== | ||
| - | |||
| - | * [[http://www.libvirt.org/]] | ||
| - | * man kvm | ||
| - | |||
| - | ===== Software ===== | ||
| - | |||
| - | Required software packages: | ||
| - | |||
| - | <file> | ||
| - | apt-get install libvirt-bin qemu-kvm qemu-utils | ||
| - | </file> | ||
| - | |||
| - | Graphical user interface: | ||
| - | |||
| - | <file> | ||
| - | apt-get install virt-manager | ||
| - | </file> | ||
| - | |||
| - | Kernel 2.6.32 and according libvirt highly recommended, e.g. Debian/squeeze and Debian/lenny with backports works fine. | ||
| - | |||
| - | ===== ifaces example ===== | ||
| - | <file> | ||
| - | # This file describes the network interfaces available on your system | ||
| - | # and how to activate them. For more information, see interfaces(5). | ||
| - | |||
| - | # The loopback network interface | ||
| - | auto lo | ||
| - | iface lo inet loopback | ||
| - | |||
| - | # bridge for kvm | ||
| - | auto eth0 | ||
| - | iface eth0 inet manual | ||
| - | |||
| - | auto vnet | ||
| - | iface vnet inet dhcp | ||
| - | bridge_ports eth0 | ||
| - | </file> | ||
| - | |||
| - | ===== Simple demo setup with Grml ISO ===== | ||
| - | |||
| - | <file> | ||
| - | cd /dev/shm | ||
| - | wget http://download.grml.org/grml-small_2010.04.iso | ||
| - | ISO=/dev/shm/grml-small_2010.04.iso | ||
| - | cat > grml.xml << EOF | ||
| - | <domain type='kvm'> | ||
| - | <name>grml-kvm</name> | ||
| - | <memory>262144</memory> | ||
| - | <currentMemory>262144</currentMemory> | ||
| - | <vcpu>1</vcpu> | ||
| - | <os> | ||
| - | <type arch='x86_64' machine='pc'>hvm</type> | ||
| - | <boot dev='cdrom'/> | ||
| - | </os> | ||
| - | <features> | ||
| - | <acpi/> | ||
| - | <apic/> | ||
| - | <pae/> | ||
| - | </features> | ||
| - | <clock offset='utc'/> | ||
| - | <on_poweroff>destroy</on_poweroff> | ||
| - | <on_reboot>restart</on_reboot> | ||
| - | <on_crash>restart</on_crash> | ||
| - | <devices> | ||
| - | <emulator>/usr/bin/kvm</emulator> | ||
| - | <disk type='file' device='cdrom'> | ||
| - | <driver name='qemu'/> | ||
| - | <source file='/grml/isos/grml-small_2010.04.iso'/> | ||
| - | <target dev='hdc' bus='ide'/> | ||
| - | <readonly/> | ||
| - | <alias name='ide0-1-0'/> | ||
| - | <address type='drive' controller='0' bus='1' unit='0'/> | ||
| - | </disk> | ||
| - | <controller type='ide' index='0'> | ||
| - | <alias name='ide0'/> | ||
| - | </controller> | ||
| - | <interface type='bridge'> | ||
| - | <source bridge='vnet'/> | ||
| - | <model type='virtio'/> | ||
| - | <alias name='net0'/> | ||
| - | </interface> | ||
| - | <serial type='pty'> | ||
| - | <source path='/dev/pts/9'/> | ||
| - | <target port='0'/> | ||
| - | <alias name='serial0'/>` | ||
| - | </serial> | ||
| - | <console type='pty'> | ||
| - | </console> | ||
| - | <input type='mouse' bus='ps2'/> | ||
| - | <graphics type='vnc' autoport='yes'/> | ||
| - | </devices> | ||
| - | </domain> | ||
| - | EOF | ||
| - | </file> | ||
| - | |||
| - | <file> | ||
| - | sudo virsh [--connect qemu:///system] | ||
| - | </file> | ||
| - | |||
| - | Inside virsh then define and start grml instance: | ||
| - | |||
| - | <file> | ||
| - | virsh # define grml.xml | ||
| - | virsh # start grml-kvm | ||
| - | </file> | ||
| - | |||
| - | List VNC port: | ||
| - | |||
| - | <file> | ||
| - | virsh # vncdisplay grml-kvm | ||
| - | :0 | ||
| - | </file> | ||
| - | |||
| - | List all defined instances: | ||
| - | |||
| - | <file> | ||
| - | virsh # list --all | ||
| - | Id Name State | ||
| - | ---------------------------------- | ||
| - | 14 grml-kvm running | ||
| - | </file> | ||
| - | |||
| - | List assigned serial console: | ||
| - | |||
| - | <file> | ||
| - | virsh # ttyconsole grml-kvm | ||
| - | /dev/pts/8 | ||
| - | </file> | ||
| - | |||
| - | Connect via serial console (choose the "Serial" boot menu entry under additional entries for "grml-small" in the bootsplash to automatically enable serial console): | ||
| - | |||
| - | <file> | ||
| - | sudo -u libvirt-qemu cu -l /dev/pts/8 | ||
| - | </file> | ||
| - | |||
| - | Connect via VNC: | ||
| - | |||
| - | <file> | ||
| - | vncviewer localhost:5900 | ||
| - | </file> | ||
| - | |||
| - | Possible falltraps while setup: | ||
| - | |||
| - | * i686 vs. x86_64 as arch type | ||
| - | * missing any defined block devices | ||
| - | * missing bridge configuration as defined in config, example for /etc/network/interfaces see above | ||
| - | |||
| - | Verify defined configuration: | ||
| - | |||
| - | <file> | ||
| - | define $FOO | ||
| - | dumpxml $FOO | ||
| - | </file> | ||
| - | |||
| - | Autostart setup: | ||
| - | |||
| - | <file> | ||
| - | autostart $HOST | ||
| - | net-auostart default | ||
| - | net-autostart --disable default | ||
| - | autostart --disable $HOST | ||
| - | </file> | ||
| - | |||
| - | Ballooning: | ||
| - | |||
| - | <file> | ||
| - | setmem $HOST 256000 | ||
| - | <currentMemory> <= <memory> -> but can be overriden via setmaxmem | ||
| - | </file> | ||
| - | |||
| - | Overbooking of CPU: | ||
| - | |||
| - | <file> | ||
| - | <vcpu>16</vcpu> | ||
| - | </file> | ||
| - | |||
| - | Tip: Disable caching in the virtualised instance so just the internal system (the system running inside the virtual machine) uses the caches (add this line inside every <disk> ... </disk> environment): | ||
| - | |||
| - | <file> | ||
| - | "<driver cache='none'/>" | ||
| - | </file> | ||
| - | |||
| - | ===== Serial console access (guest) ===== | ||
| - | |||
| - | Adjust Grub2 configuration /etc/default/grub: | ||
| - | |||
| - | <file> | ||
| - | GRUB_CMDLINE_LINUX="console=ttyS0,115200n8" | ||
| - | GRUB_SERIAL_COMMAND="serial --speed=1152200 --unit=0 --word=8 --parity=no --stop=1" | ||
| - | </file> | ||
| - | |||
| - | Adjust /etc/inittab for serial console access: | ||
| - | |||
| - | <file> | ||
| - | T0:23:respawn:/sbin/getty -L ttyS0 115200 vt100 | ||
| - | </file> | ||
| - | |||
| - | ==== Tips ==== | ||
| - | |||
| - | Convert file config in the native guest configuration format named by format to a domain XML format: | ||
| - | |||
| - | <file> | ||
| - | virsh [--connect qemu:///system domxml-to-native] domxml-to-native qemu-argv /dev/shm/grml.xml | ||
| - | </file> | ||
| - | |||
| - | virsh like console access to kvm/qemu: | ||
| - | |||
| - | <file> | ||
| - | kvm [...] -monitor stdio | ||
| - | </file> | ||
| - | |||
| - | Block device: | ||
| - | |||
| - | <file> | ||
| - | qemu-img create -f qcow2 block.img 1G | ||
| - | |||
| - | <disk type='block' device='disk'> | ||
| - | <driver cache='none'/> | ||
| - | <source dev='/dev/shm/block.img'/> | ||
| - | <target dev='vda' bus='virtio'/> | ||
| - | <alias name='virtio-disk0'/> | ||
| - | </disk> | ||
| - | </file> | ||
| - | |||
| - | ---- | ||
| - | |||
| - | {{tag>workshop}} | ||
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