Xen Summit 2008 Tokyo

2008/11/21

paperboy&co.

Gosuke Miyashita

Agenda

About me Purpose of this talk What is libvirt libvirt Xen driver architecture libvirt sample codes with Perl/Python Related tools (Avahi and Func)

About me

Gosuke Miyashitahttp://mizzy.org/

Technical manager at paperboy&co.Web hosting, blog, ec hosting and so on for

indivisuals

Thinking introduce virtualization technologies to our services

Purpose of this talk I seek how to manage Xen domains on

many host machines I need a simple and customizable tool It may be fast to develop my own tool libvirt is the one for developing my own

Xen management tool Why python and perl?

These languages may be used widly in system administration

What is libvirt? The virtualization API A library intracts with virtualization

systemsXen, QEMU, KVM, LXC and OpenVZ

Language bindingsC, Python, Perl, OCaml, Ruby, Java and C#

Support multiple authentication methodsSSH, TLS and X.509, SASL and Kerberos

Avahi multicast DNS support

What can you do with libvirt? Get Dom0 info

CPU model/threads/cores, memory size and so on List domains Get domain info

id, uuid, name, xml description, os type and state Various domain operations

create, shutdown, reboot, suspend, resumeset/get max memory/memory size, get max vcpus

Network, Storage operations (excluded in this talk)

See http://libvirt.org/html/libvirt-libvirt.html

libvirt Xen driver(local)

xend xenstored xen hypervisor

libvirt

Perl Python OCaml RubyJava C#C

libvirt Xen driver(remote)

xend xenstored xen hypervisor

libvirtd

Perl Python OCaml RubyJava C#C

libvirt

Over a network

Perl code exampleuse Sys::Virt;

# connect to the remote hostmy $vmm = Sys::Virt->new( uri => "xen://remote_host/“ );

# get domainsmy @doms = $vmm->list_domains;

# print state of each domainsfor my $dom ( @doms ) { printf "%s: %s\n", $dom->get_name, $dom->get_info->{state};}

Python code exampleimport libvirt

# connect to the remote hostconn = libvirt.open(‘xen://remote_host/’)

# get domain idsids = conn.listDomainsID()

# print state of each domainsfor id in ids: vm = conn.lookupByID(id) print "%s: %s" % ( vm.name(), vm.info()[0] )

Avahi support

libvirt is integrated with Avahi Ahahi is a one of mDNS implementation You can discover hosts with libvirtd

running by mDNS client automatically

Perl example with libvirt and avahiuse Net::Bonjour;use Sys::Virt;

# discover hosts with libvirtd runningmy $res = Net::Bonjour->new('libvirt');$res->discover;

# access libvirtd on each hostfor my $host ( $res->entries ) { my $vmm = Sys::Virt->new( uri => ‘xen://’ . $host->address ); ....}

Func Fedora Unified Network Controller

https://fedorahosted.org/func/ Sysadmin application framework made

of Python A programming framework for “Exec

some operations for multiple hosts” Many modules

yum, user, service, command, smart, virt ... Virt module uses libvirt

Func virt module sample codeimport func.overlord.client as fc

# call state method of virt module on all hostsresults = fc.Client("*").virt.state()

# create domain if domain state is ‘shutdown’for ( host, vms ) in results.iteritems(): if vms[0] == 'REMOTE_ERROR': continue

for vm in vms: ( domain, state ) = vm.split(' ') if state == 'shutdown': fc.Client(host).virt.create(domain)