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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>