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h1. Cluster with libvirt

h2. Tooling

<pre>

# cd /root/tools/libvirt/

# ./autovirsh domuuid gizmo.sileht.net
Domain gizmo.sileht.net is on g3
4baace2f-6d7c-4575-8982-bedb6065ab6b

# ./where www.tetaneutral.net
Domain www.tetaneutral.net is on g1

# ./create-vm --help
usage: create-vm --ip IP NAME
--image debian-buster-scsi
--ram 1 # SIZE in GiB
--vcpu 1
--ip <IPV4>
--disk 20 # SIZE in GiB
--on g1 # short name of the host

# ./migrate --help
usage: migrate NAME DEST

# ./info gizmo.sileht.net
Domain gizmo.sileht.net is on g3
Interface Type Source Model MAC
-------------------------------------------------------
tap249cbb03-b8 ethernet - virtio fa:16:3e:88:4d:0b

Target Source
------------------------------------------------
hda ssds/97c925e4-9f3e-4b92-96b9-6190e0fc4b88_disk.config
sda ssds/volume-0973c10d-79c8-4906-9f9c-9ba33118203d
sdb disks/volume-3657e47a-07d8-4052-8dcf-cb7a0fb19b20

<config>
<tap name="tap249cbb03-b8">91.224.149.214</tap>
</config>

</pre>

h2. Fontionnement

Les VM utilisent le mode ethernet de libvirt. En gros libvirt s'attends à trouver un tap tout près pour y accrocher la VM

Just avant le boot de la VM libvirt lance:

<pre> /etc/libvirt/hooks/qemu <VM_NAME> prepare begin</pre>

Et juste après l'arret de la VM libvirt lance:

<pre> /etc/libvirt/hooks/qemu <VM_NAME> release end</pre>

Le script /etc/libvirt/hooks/qemu de ttnn se trouve ici: https://chiliproject.tetaneutral.net/projects/git-tetaneutral-net/repository/puppetmaster/revisions/master/entry/environments/production/manifests/files/openstack/libvirt-hooks-qemu

Ce script va lire les metadatas TTNN de <VM_NAME> (e.g: virsh metadata <VM_NAME> http://tetaneutral.net/)

<pre>
$ virsh metadata ns2.tetaneutral.net http://tetaneutral.net/
<config>
<network mode="routed">
<tap name="tapb0b4a106-d0">89.234.156.248</tap>
<tap name="tapabababab-aa">89.234.156.45</tap>
</network>
</config>
</pre>

Ensuite il va créé le tap et configurer les routes dessus avec les infos des metadata.

h2. git

https://chiliproject.tetaneutral.net/projects/git-tetaneutral-net/repository/openstack-tools

libvirt

h2. Misc



h3. Editer le disque d'une VM

Mode lecture seule (sans danger) :
<pre>
VM=xxx
virsh shutdown $VM
virsh destroy $VM # si shutdown marche pas
guestfish --ro -i -d $VM
</pre>

Pour par exemple desactiver cloud-init qui peut bloquer le boot :

<pre>
guestfish -i -d $VM
ll /etc/cloud
touch /etc/cloud/cloud-init.disabled
exit
</pre>

h3. Voir la console graphique sans spice-html5:

Copier le script suivant 'ttnn-viewer' sur sa machine:

<pre>
#!/bin/bash
vm=$1
info=$(ssh g1.tetaneutral.net -p 2222 -l root -- "tools/libvirt/where $vm|cut -d' ' -f5")

if [ x"${info}" == "x" ]; then
echo "Error VM $vm not found"
exit 1
fi

hypervisor=${info}.tetaneutral.net
spice_port=$(ssh ${hypervisor} -p 2222 -l root virsh domdisplay ${vm} | awk -F: '{print $3}')

echo "$vm on $hypervisor port $spice_port"
ssh -N $hypervisor -p 2222 -l root -L 5910:localhost:${spice_port} &
pid=$!

cleanup(){
kill $pid
}

trap cleanup EXIT

sleep 2
remote-viewer spice://localhost:5910/
</pre>

Puis

<pre>
sudo apt-get install virt-viewer
./ttnn-viewer puppet.tetaeutral.net
</pre>