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Joris Michaux, 06/05/2013 17:19
Libvirt¶
Resources/Liens¶
- Virtualisation du routage IPv4 pour les VM http://lists.tetaneutral.net/pipermail/technique/2013-April/000810.html
- libvirt
http://builder.virt-tools.org/artifacts/libvirt-virshcmdref/html/index.html
http://docs.fedoraproject.org/en-US/Fedora/13/html/Virtualization_Guide/chap-Virtualization-Managing_guests_with_virsh.html
- virt-install et preseed sans server web et pxe:
http://honk.sigxcpu.org/con/Preseeding_Debian_virtual_machines_with_virt_install.html
Installation VM sans bridge avec routage static (en /32 pour l'ipv4)¶
Note: tous les fichiers utilisés et créés ne sont peut être pas à jour, voir ici pour les dernières version: http://git.tetaneutral.net/libvirt.git/
Le répertoire /etc/libvirt/ttnn cité plustard est géré dans ce git.
Configuration de la libvirt¶
On créé un réseau libvirt qui fait rien (déjà fait sur n7):
cat > libvirt_dump_network.xml <<EOF <network ipv6='yes'> <name>dump-net</name> <bridge name='dumpbr0' /> </network> EOF virsh net-define libvirt_dump_network.xml virsh net-autostart dump-net virsh net-start dump-net
On créé un hook libvirt (déjà fait sur n7):
mkdir -p /etc/libvirt/ttnn/hooks ln -s /etc/libvirt/ttnn/hooks /etc/libvirt/hooks vi /etc/libvirt/hooks/qemu ----8<--------------->8---- #!/bin/bash name="$1" operation="$2" suboperation="$3" [ "$operation" != "start" ] && exit 0 [ "$suboperation" != "begin" ] && exit 0 # get interface from the libvirt xml interface=$(cat - | sed -ne "/vnet/s/.*dev='\([^']*\)'.*/\1/gp") [ -f /etc/libvirt/ttnn/${name}.conf ] && source /etc/libvirt/ttnn/${name}.conf [ "$ip" -o "$ip6" ] && brctl delif dumpbr0 $interface [ "$ip" ] && ip route add $ip/32 dev $interface [ "$ip6" ] && ip route add $ip6/56 dev $interface [ "$ip6" ] && ip -6 addr add fe80::31/64 dev $interface exit 0 ----8<--------------->8----
Preparation de l'installer¶
Pour une squeeze on met à jour virtinst (déjà fait sur n7):
wget http://ftp.us.debian.org/debian/pool/main/v/virtinst/virtinst_0.600.3-3_all.deb dpkg -i virtinst_0.600.3-3_all.deb
On install le preseed.cfg attaché à la page dans /etc/libvirt/preseed.cfg (déjà fait sur n7)
Installation d'une VM¶
Creation du disk (déjà fait sur n7):
lvcreate -n picttn -L 50G /dev/raid5
Configuration du routage static:
vi /etc/libvirt/ttnn/picttn.conf # le /32 ipv4 ip="91.224.148.252" # le /56 ipv6 ip6="2a01:6600:8080:FC00::"
Lancement de l'installation via le réseau natter de libvirt
virt-install -n picttn -r 2048 --os-type=linux \ --autostart \ --disk /dev/raid5/picttn,bus=virtio,cache=none,io=native \ --network network=default,model=virtio \ --nographics \ --noreboot \ --wait -1 \ --location http://ftp.debian.org/debian/dists/wheezy/main/installer-amd64/ \ --serial pty \ --initrd-inject /etc/libvirt/ttnn/preseed.cfg \ --initrd-inject /etc/libvirt/ttnn/picttn.conf \ --initrd-inject /etc/libvirt/ttnn/postinstall.sh \ --extra-args "console=ttyS0,9600n8 DEBIAN_FRONTEND=text auto priority=critical hostname=picttn domain=le-pic.org"
Une fois l'installation terminée, on change la conf réseau:
EDITOR="sed -ie s/default/dump-net/g" virsh edit picttn
On peux démarrer la VM
virsh start picttn virsh console picttn
Ensuite on peux se connecte à la VM
ssh root@2a01:6600:8080:FC00::1
Le /etc/network/interfaces IPv4 après installation
iface eth0 inet static address 91.224.148.xxx netmask 32 up ip route add 91.224.148.0/32 dev eth0 up ip route add default via 91.224.148.0
Misc¶
<H4Mm3r> si tu lance la création de la VM sans avoir créé le disk --disk /vmroot/testnat.qcow2,format=qcow2,size=12,bus=virtio,cache=writeback
<H4Mm3r> le disk se créé mais dans le XML le format est à RAW
<H4Mm3r> si tu le créé à l'avance avec qemu-img create -f qcow2
<H4Mm3r> et que tu lance ta commande --disk /vmroot/testnat.qcow2,format=qcow2
<guerby> ok donc c'etait bien ça :)
<guerby> bbl (miam)
<H4Mm3r> dans le fichier XML le format est à RAW
<H4Mm3r> il faut en effet dumper un XML, modifier la valeur à QCOW2
<H4Mm3r> et créer la VM depuis ce XML
<H4Mm3r> virsh create file.xml
<H4Mm3r> pourqu'enfin il comprenne que c'est du QCOW...
<H4Mm3r> et là mon disk fait bien 265ko, mais est détecté comme 12G :D
HOWTO by H4Mm3r (under contruction)¶
Usefull links¶
- Misc
#OS Type
http://rhevdup.blogspot.fr/2012/05/list-available-os-types-for-kvm-on-rhel.html
#Libvirt TTN
http://chiliproject.tetaneutral.net/projects/tetaneutral/wiki/Libvirt
- KVM management
#Install QEMU KVM + LIBVIRT
http://www.howtoforge.com/virtualization-with-kvm-on-a-debian-squeeze-server
#Edit XML file
http://vladnevzorov.com/2011/02/11/how-to-change-configuration-of-kvm-virtual-machine/
#Clone a KVM
https://help.ubuntu.com/community/KVM/CreateGuests#Cloning_a_virtual_machine
http://linux.die.net/man/1/virt-clone
- Network
#NAT
http://www.linuxquestions.org/questions/linux-networking-3/kvm-qemu-and-nat-on-the-host-machine-mini-tutorial-697980/
http://wiki.libvirt.org/page/Networking
http://libvirt.org/formatnetwork.html#examplesNAT
https://help.ubuntu.com/community/KVM/Networking
#Bridge
http://toast.djw.org.uk/qemu.html
http://www.mediaonfire.com/en/tech_tips/QEMUNetworking.html (bridge, nat, arp)
- Improve performance
http://blog.bodhizazen.net/linux/improve-kvm-performance/
http://www.linux-kvm.org/page/Tuning_KVM
http://www.ezunix.org/index.php?title=Boost_performance_of_KVM_guests
HOWTO¶
[H] = Host [G] = Guest [XML] = XML content "command"
- Diskfile Storage
#Create qcow2 disk
[H] "qemu-img create -f qcow2 /path/to/disk.qcow2 $SIZE" (ex: 20G) [H] "chmod +x /path/to/disk.qcow2"
#Convert raw to qcow2
[H] "qemu-img convert -O qcow2 disk.img disk.qcow2"
#Disable cache to improve performance
[XML] <driver name='qemu' type='qcow2' cache='none'/>
- LVM Storage
[H] Create "/etc/libvirt/storage/vmdata.xml" file : <pool type="logical"> <name>my_pool</name> <source> <device path="/path/to/dev"/> </source> <target> <path>/target/path/path> (LV will be created there) </target> </pool> [H] "virsh pool-define /etc/libvirt/storage/my_pool.xml" [H] "virsh pool-start my_pool" [H] "virsh pool-autostart my_pool" [H] "virsh pool-info my_pool" [H] "virsh vol-create-as my_pool my_logical_volume 12G" [H] You must create a LV to be able to give it to a KVM "virsh vol-create-as my_pool my_vol 12G --format=lvm2"
Create KVM¶
#Bridged with TAP + LVM
[H] "virt-install -d --hvm --vnc --name=my_kvm --vcpus=4 --cpuset=0-4 --ram 2048 --disk vol=my_pool/my_vol,bus=virtio,cache=none --network bridge=my_bridge,model=virtio -c /path/to/distrib.iso --keymap=fr --os-type=linux --noautoconsole"
#TAP (if you want to rename the default "vnetX" interface by "tapX"
[H] "virsh dumpxml my_guest > my_guest.xml [H] "virsh undefine my_guest" [H] Edit the my_guest.xml file to rename VNETX by TAPX [H] "virsh define my_guest.xml" [H] "virsh start my_guest"
#NATed + LVM
[H] "virt-install -d --hvm --vnc --name=my_kvm --vcpus=4 --cpuset=0-4 --ram 2048 --disk vol=my_pool/my_vol,bus=virtio,cache=none --network network=my_network,model=virtio -c /path/to/distrib.iso --keymap=fr --os-type=linux --noautoconsole"
#Clone VM
[H] Create the LVM dest [H] Pause the KVM "virsh suspend my_kvm" [H] virt-clone -o my_orig_kvm -n my_cloned_kvm -f=/path/to/lvm/dev [G] Go and change the hostname and resolv.conf
Command explanation¶
#Bridged with tap
virt-install -d --hvm --vnc --name=testlvm \ --vcpus=4 --cpuset=0-4 \ --ram 2048 \ --disk vol=vmdata/testlvm,bus=virtio,cache=none \ --network bridge=br0,model=virtio \ -c /data/isos/debian-testing-amd64-netinst.iso \ --keymap=fr --os-type=linux --os-variant=debiansqueeze --noautoconsole
#NATed
virt-install -d --hvm --vnc --name=testlvm \ --vcpus=4 --cpuset=0-4 \ --ram 2048 \ --disk vol=vmdata/testlvm,bus=virtio,cache=none \ --network network=frp_network,model=virtio \ -c /data/isos/debian-testing-amd64-netinst.iso \ --keymap=fr --os-type=linux --os-variant=debiansqueeze --noautoconsole
[OLD QCOW2]
[H] "virt-install --connect qemu:///system -n puppetnode1 -r 1024 --vcpus=4 --cpuset=4-7 --disk path=/vmroot/puppetnode1.qcow2 -c /data/isos/debian-6.0.6-amd64-netinst.iso --vnc --keymap=fr --noautoconsole --os-type linux --os-variant debiansqueeze --accelerate --network network=default --hvm" [H] "virt-install --connect qemu:///system -n testnat -r 1024 --vcpus=2 --cpuset=2-3 --disk /vmroot/testnat.qcow2,format=qcow2,size=12,bus=virtio,cache=writeback -c /data/isos/debian-6.0.6-amd64-netinst.iso --vnc --keymap=fr --noautoconsole --os-type linux --os-variant debiansqueeze --accelerate --network bridge=br0 --hvm"
#Start a KVM
[H] "virsh start my_kvm"
#Stop node
[H] Soft : "virsh shutdown my_kvm" [H] Hard : "virsh destroy my_kvm"
#Suppr node del
[H] "virsh undefine node" (+ remove files)
#Rename node
[H] "virsh dumpxml my_kvm > foo.xml" [H] <edit foo.xml, change the name, move storage> [H] "virsh undefine my_kvm" [H] "virsh define foo.xml"
- Connect to virsh qemu
[H] "virsh --connect qemu:///system" [H] "virsh # help"
#Start a network
[H] "virsh net-start my_network"
#Configure VNC
[H] Edit /etc/libvirt/qemu.conf and set vnc_listen = "your.ip.addd" [H] You need to restart service "/etc/init.d/libvirtd restart" [H] "ps aux | grep -i kvm" (find vnc display for your KVM)
#Connect to a KVM through VNC
tightvncviewer -compresslevel 7 -encodings "copyrect tight hextile zlib corre rre raw" x.xxx.xxx.xxx:x
#Keyboard FR for KVM
[H] "virsh edit my_kvm" [XML] <graphics type='vnc' port='-1' autoport='yes' keymap='fr'/>
#Create your own NAT network
[H] Create your_nat.xml file : [XML] <network> <name>frp_network</name> <forward mode='nat'/> <bridge name='br1' stp='on' delay='0' /> <ip address='10.16.42.1' netmask='255.255.255.0'> <dhcp> <range start='10.16.42.2' end='10.16.42.50' /> </dhcp> </ip> </network> [H] "virsh net-define your_nat.xml" [H] "virsh net-start your_nat.xml" [H] "virsh net-autostart your_nat.xml" [XML] Network type "interface type = network, source network=your_nat"
#IBM advisements to improve performance
[H] Use LVM (or other direct access to HDD) for VMs storage (from 45 to 3' to install a VM) [H] Set the swappiness value to 0 ("echo 0 > /proc/sys/vm/swappiness" && edit "/etc/sysctl.conf" and add "vm.swappiness=0") [H] Disable zone_reclaim ("echo 0 > /proc/sys/vm/zone_reclaim_mode" && edit "/etc/sysctl.conf" and add "vm.zone_reclaim_mode=0") [H] Enable KSM ("echo 1 > /sys/kernel/mm/ksm/run") and set the check time to 200ms ("echo 200 > /sys/kernel/mm/ksm/sleep_millisecs")