[one-users] Avoiding manual restart of (persistent) VMs in case of host reboot

[Olivier Berger]

Hi.

Responding to myself ...

On Wed, 23 May 2012 17:03:44 +0200, Olivier Berger <olivier.berger at it-sudparis.eu> wrote:
> Hi.
> 
> On Wed, 23 May 2012 16:09:20 +0200, Jaime Melis <jmelis at opennebula.org> wrote:
> > 
> > You could do two things:
> > 1) Write a hook [1] on the event of running vm to do "virsh autostart
> > one-<VM_ID>" [2]
> > 2) Add a line in the deployment script [3] to execute "virsh autostart
> > one-<VM_ID>" ( after line 29 of the script for example)
> > 
> > [1] http://libvirt.org/sources/virshcmdref/html/sect-autostart.html
> > [2]
> > http://opennebula.org/documentation:rel3.4:hooks#hooks_for_virtualmachines
> > [3]
> > https://github.com/OpenNebula/one/blob/one-3.2/src/vmm_mad/remotes/kvm/deploy#L29
> > 
> 
> Hmmm... I've tried this, but :
> 
> # virsh autostart one-42
> error: Failed to mark domain one-42 as autostarted
> error: Requested operation is not valid: cannot set autostart for transient domain
> 
> Maybe the result would be different if run from the hook / script, but
> I'm not sure...
> 
> From reading http://remoteoutpost.nl/?page_id=71 I've understood that
> the virsh define command was needed, so I've tried adding that deployment
> script (which I believe is /var/lib/one/remotes/vmm/kvm/deploy), doing :
> 
>  virsh --connect $LIBVIRT_URI define $domain 
> 
> just before the :
> 
>  data=`virsh --connect $LIBVIRT_URI create $domain`
> 
> However, it doesn't seem to be executed :-/
> 

Ah, yes, I was changing the one in /var/lib/one instead of the one
"deployed on the node", but actually on the same host in
/var/tmp/one... (newbie mode)


So, the following in vmm/kvm/deploy should do the trick :

domain=$1

mkdir -p `dirname $domain`
cat > $domain

# First define the xml file as a domain definition
data=`virsh --connect $LIBVIRT_URI define $domain`
if [ "x$?" = "x0" ]; then
    vm=`echo $data | sed 's/Domain //' | sed 's/ defined from .*$//'`

    # start the VM/domain
    data=`virsh --connect $LIBVIRT_URI start $vm`

    if [ "x$?" = "x0" ]; then
       echo $data | sed 's/Domain //' | sed 's/ started.*$//'
       # set it as autostart in case of node reboot
       virsh  --connect $LIBVIRT_URI autostart $vm
    else
       error_message "Could not create domain from $domain"
       exit -1
    fi
else
    error_message "Could not define domain from $domain"
    exit -1
fi

This seems to allow the VM to be restarted/resumed (still need to
investigate exactly) in case of node reboot.

Hope this helps,

Best regards.
-- 
Olivier BERGER 
http://www-public.it-sudparis.eu/~berger_o/ - OpenPGP-Id: 2048R/5819D7E8
Ingenieur Recherche - Dept INF
Institut Mines-Telecom, Telecom SudParis, Evry (France)