dnsmasq

libvirt utilise dnsmasq

Exemple de fichier de configuration:

strict-order
pid-file=/var/run/libvirt/network/default.pid
except-interface=lo
bind-dynamic
interface=virbr0
dhcp-range=192.168.122.2,192.168.122.254
dhcp-no-override
dhcp-leasefile=/var/lib/libvirt/dnsmasq/default.leases
dhcp-lease-max=253
dhcp-hostsfile=/var/lib/libvirt/dnsmasq/default.hostsfile
addn-hosts=/var/lib/libvirt/dnsmasq/default.addnhosts

dnsmasq est lancé par libvirt avec la ligne de commande :

/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --dhcp-script=/usr/libexec/libvirt_leaseshelper

/usr/libexec/libvirt_leaseshelper est un binaire

Création d'un bridge

Création du bridge sur l'hôte avec NetworkManager

nmcli connection add type bridge ifname br0
nmcli connection add type bridge-slave ifname p4p2 master br0
nmcli connection up bridge-br0

Déclaration dans libvirt

cat > br0.xml<<EOF_NET
<network>
   <name>br0</name>
   <forward mode="bridge" />
   <bridge name="br0" />
</network>
EOF_NET
virsh net-define br0.xml
virsh net-start br0
virsh net-autostart br0
virsh net-list

Installation Centos 7 minimal

J'utilise le Cd d'installation de CentOS. Je choisis l'installation minimal. Le kickstart contient l'installation du groupe de paquets @core Le réseau est configuré mais pas lancé au démarrage. Le système utilise env 1GB de dd.

[user@localhost ~]$ df -H
Sys. de fichiers        Taille Utilisé Dispo Uti% Monté sur
/dev/mapper/centos-root   4,3G    833M  3,5G  20% /
devtmpfs                  515M       0  515M   0% /dev
tmpfs                     522M       0  522M   0% /dev/shm
tmpfs                     522M    7,0M  515M   2% /run
tmpfs                     522M       0  522M   0% /sys/fs/cgroup
/dev/vda1                 521M    101M  420M  20% /boot

Création d'une VM centOS

En utilisant le dépôt officiel

virt-install --name srv01 --ram 1024  --vcpus=1 --os-variant=rhel7 --boot cdrom,network --disk /home/depots/Virtu/Kvm/srv01.qcow2,size=5 --initrd-inject=/tmp/srv01.ks  --extra-args "ks=file:/my.ks" --location http://mirror.centos.org/centos/7/os/x86_64/

En utilisant l'image iso téléchargée précédemment

sudo  mount -oloop /home/depots/ISO/CentOS-7-x86_64.iso /mnt
    virt-install --name srv01 --ram 1024  --vcpus=1 --os-variant=rhel7 --boot cdrom,network --disk /home/depots/Virtu/Kvm/srv01.qcow2,size=5 --initrd-inject=/tmp/srv01.ks  --extra-args "ks=file:/my.ks" --location  /mnt

Annexes

#version=RHEL7
# System authorization information
auth --enableshadow --passalgo=sha512

# Use CDROM installation media
cdrom
# Run the Setup Agent on first boot
firstboot --enable
ignoredisk --only-use=vda
# Keyboard layouts
keyboard --vckeymap=fr --xlayouts='fr (oss)'
# System language
lang fr_FR.UTF-8

# Network information
network  --bootproto=dhcp --device=eth0 --onboot=off --ipv6=auto
network  --hostname=localhost.localdomain
# Root password: {tootoor}!
rootpw --iscrypted $6$0rWj5wdTTvCfY4ak$uTBvgroOoeqHqjO.kvgBN2kyLaDvw7pmTzsY8c3MjA9LLllL3gmo4f5vAEZpdj75Eic06LByjCb0lg.i2K.lT.
# System timezone
timezone Europe/Paris --isUtc
# user passwd is : +install00!
user --groups=wheel --homedir=/home/user --name=user --password=$6$7C4NqqetkHmanVCv$LqQnmhs9Py8JaYXEOBg6ct47gn/n1VsEBvjmFQLzqjjGDr3V.FpMfWjeARySG07ycPHIb.MYyhIhmUJW.Z4KS0 --iscrypted --gecos="user"
# System bootloader configuration
bootloader --location=mbr --boot-drive=vda
autopart --type=lvm
# Partition clearing information
clearpart --none --initlabel

%packages
@core

# network is down
# to launch it, just run sudo ifup eth0
# set --onboot parameter to on to enable interface on boot.
# sshd is launched


%end

Les hooks dans Libvirt

TODO: étudier cette histoire de hooks !!

Créer le fichier dans /etc/libvirt/hooks/qemu

!/bin/bash
# used some from advanced script to have multiple ports: use an equal number of guest and host ports


echo `date` hook/qemu "${1}" "${2}" >>/root/hook.log


# Update the following variables to fit your setup


### First VM
Guest_name=VM_1_NAME
Guest_ipaddr=192.168.122.4
Host_port=(  '1234' )
Guest_port=( '22' )


length=$(( ${#Host_port[@]} - 1 ))
if [ "${1}" = "${Guest_name}" ]; then
if [ "${2}" = "stopped" ] || [ "${2}" = "reconnect" ]; then
    for i in `seq 0 $length`; do
            echo "kvm-Ho." >>/root/hook.log
            /sbin/iptables -D FORWARD -o virbr0 -d  ${Guest_ipaddr} -j ACCEPT
            /sbin/iptables -t nat -D PREROUTING -p tcp --dport ${Host_port[$i]} -j DNAT --to ${Guest_ipaddr}:${Guest_port[$i]}
    done
fi
if [ "${2}" = "start" ] || [ "${2}" = "reconnect" ]; then
    for i in `seq 0 $length`; do
            echo "kvm-Hey." >>/root/hook.log
            /sbin/iptables -I FORWARD -o virbr0 -d  ${Guest_ipaddr} -j ACCEPT
            /sbin/iptables -t nat -I PREROUTING -p tcp --dport ${Host_port[$i]} -j DNAT --to ${Guest_ipaddr}:${Guest_port[$i]}
    done
fi
fi