[Kimchi-devel] [PATCH 2/3] Live migration backend: control/vms and model/vms changes
Paulo Ricardo Paz Vital
pvital at linux.vnet.ibm.com
Tue Oct 27 17:11:42 UTC 2015
On Tue, 2015-10-27 at 11:37 -0200, Daniel Henrique Barboza wrote:
>
> On 10/27/2015 08:38 AM, Paulo Ricardo Paz Vital wrote:
> > On Mon, 2015-10-26 at 16:08 -0200, dhbarboza82 at gmail.com wrote:
> > > From: Daniel Henrique Barboza <dhbarboza82 at gmail.com>
> > >
> > > This patch adds the backend code to support live (and cold)
> > > migration
> > > in Kimchi.
> > >
> > > Signed-off-by: Daniel Henrique Barboza <dhbarboza82 at gmail.com>
> > > ---
> > > src/wok/plugins/kimchi/control/vms.py | 3 ++
> > > src/wok/plugins/kimchi/model/vms.py | 68
> > > ++++++++++++++++++++++++++++++++++-
> > > 2 files changed, 70 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/src/wok/plugins/kimchi/control/vms.py
> > > b/src/wok/plugins/kimchi/control/vms.py
> > > index 58d4b67..5e24538 100644
> > > --- a/src/wok/plugins/kimchi/control/vms.py
> > > +++ b/src/wok/plugins/kimchi/control/vms.py
> > > @@ -49,6 +49,9 @@ class VM(Resource):
> > >
> > > destructive=True)
> > > self.connect = self.generate_action_handler('connect')
> > > self.clone = self.generate_action_handler_task('clone')
> > > + self.migrate =
> > > self.generate_action_handler_task('migrate',
> > > +
> > > ['remote_host',
> > > +
> > > 'user'])
> > > self.suspend = self.generate_action_handler('suspend')
> > > self.resume = self.generate_action_handler('resume')
> > >
> > > diff --git a/src/wok/plugins/kimchi/model/vms.py
> > > b/src/wok/plugins/kimchi/model/vms.py
> > > index 60145d0..5d242e8 100644
> > > --- a/src/wok/plugins/kimchi/model/vms.py
> > > +++ b/src/wok/plugins/kimchi/model/vms.py
> > > @@ -36,7 +36,7 @@ from wok.exception import NotFoundError,
> > > OperationFailed
> > > from wok.model.tasks import TaskModel
> > > from wok.rollbackcontext import RollbackContext
> > > from wok.utils import add_task, convert_data_size,
> > > get_next_clone_name
> > > -from wok.utils import import_class, run_setfacl_set_attr,
> > > wok_log
> > > +from wok.utils import import_class, run_setfacl_set_attr,
> > > run_command, wok_log
> > > from wok.xmlutils.utils import xpath_get_text, xml_item_update
> > > from wok.xmlutils.utils import dictize
> > >
> > > @@ -1294,6 +1294,72 @@ class VMModel(object):
> > > raise OperationFailed('KCHVM0040E', {'name': name,
> > > 'err':
> > > e.message})
> > >
> > > + def _check_if_host_not_localhost(self, remote_host):
> > > + if remote_host in ['localhost', '127.0.0.1']:
> > > + raise OperationFailed("KCHVM0055E", {'host':
> > > remote_host})
> > Only a curiosity: Is it OK accept the hostname or IP address of my
> > 'localhost', or only these two cases are not a good case to
> > migrate?
> Libvirt will freak out if you try to do a 'migrateinception' :P
>
> This is why I've made this verification - to ensure that the user
> doesn't pass the
> IP/hostname of the same host Kimchi is running on by accident.
>
>
So, if I'm running Kimchi in a machine called 'bla.br.ibm.com' and use
this hostname to realize a migration, libvirt will freakout, right?!?!
I suggest to check not only the name 'localhost' and IP '127.0.0.1',
but also the IP address and real hostname of the machine.
> >
> >
> > > +
> > > + def _check_if_password_less_login_enabled(self, remote_host,
> > > user):
> > > + username_host = "%s@%s" % (user, remote_host)
> > > + ssh_cmd = ['ssh', '-oNumberOfPasswordPrompts=0',
> > > + '-oStrictHostKeyChecking=no', username_host,
> > > + 'echo', 'hello']
> > > + stdout, stderr, returncode = run_command(ssh_cmd, 5,
> > > silent=True)
> > > + if returncode != 0:
> > > + raise OperationFailed("KCHVM0056E",
> > > + {'host': remote_host, 'user':
> > > user})
> > > +
> > > + def _get_remote_libvirt_conn(self, remote_host,
> > > + user='root', transport='ssh'):
> > > + dest_uri = 'qemu+%s://%s@%s/system' % (transport, user,
> > > remote_host)
> > > + # TODO: verify why LibvirtConnection(dest_uri) does not
> > > work
> > > here
> > > + return libvirt.open(dest_uri)
> > > +
> > > + def migration_pre_check(self, remote_host, user):
> > > + self._check_if_host_not_localhost(remote_host)
> > > + self._check_if_password_less_login_enabled(remote_host,
> > > user)
> > > +
> > > + def migrate(self, name, remote_host, user='root'):
> > > + name = name.decode('utf-8')
> > > + remote_host = remote_host.decode('utf-8')
> > > +
> > > + self.migration_pre_check(remote_host, user)
> > > + dest_conn = self._get_remote_libvirt_conn(remote_host)
> > > +
> > > + params = {'name': name,
> > > + 'dest_conn': dest_conn}
> > > + task_id = add_task('/vms/%s/migrate' % name,
> > > self._migrate_task,
> > > + self.objstore, params)
> > > +
> > > + return self.task.lookup(task_id)
> > > +
> > > + def _migrate_task(self, cb, params):
> > > + name = params['name'].decode('utf-8')
> > > + dest_conn = params['dest_conn']
> > > +
> > > + cb('starting a migration')
> > > +
> > > + dom = self.get_vm(name, self.conn)
> > > + state = DOM_STATE_MAP[dom.info()[0]]
> > > +
> > > + flags = libvirt.VIR_MIGRATE_PEER2PEER
> > > + if state == 'shutoff':
> > > + flags |= (libvirt.VIR_MIGRATE_OFFLINE |
> > > + libvirt.VIR_MIGRATE_PERSIST_DEST)
> > > + elif state in ['running', 'paused']:
> > > + flags |= libvirt.VIR_MIGRATE_LIVE |
> > > libvirt.VIR_MIGRATE_TUNNELLED
> > > + if dom.isPersistent():
> > > + flags |= libvirt.VIR_MIGRATE_PERSIST_DEST
> > > + else:
> > > + raise OperationFailed("KCHVM0057E", {'name': name,
> > > + 'state':
> > > state})
> > > + try:
> > > + dom.migrate(dest_conn, flags)
> > > + except libvirt.libvirtError as e:
> > > + cb('Migrate failed', False)
> > > + raise OperationFailed('KCHVM0058E', {'err':
> > > e.message,
> > > + 'name': name})
> > > + cb('Migrate finished', True)
> > > +
> > >
> > > class VMScreenshotModel(object):
> > > def __init__(self, **kargs):
>
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