openstack/nova
Code Issues Proposed changes

libvirt: prepare domain XML update for serial ports

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The serial console feature uses "ports" on a compute node to enable
a websocket connection. On a host, one port can only be used by one
single instance. If another instance gets live-migrated to that host,
an update of the ports in the domain XML is needed. Otherwise we will
get an exception from libvirt/qemu which states:

    Failed to bind socket: Cannot assign requested address

This change here *prepares* the update of the domain XML. Another change
is necessary which actually provides the ports to use for this update
function within the LibvirtLiveMigrateData object.

This change is a preparation for the fix of bug 1455252.

Co-Authored-By: Sahid Orentino Ferdjaoui <sahid.ferdjaoui@redhat.com>
Change-Id: I531ec76bc82beaea89f3a94a72e8a75627a9aa23
This commit is contained in:
Markus Zoeller 2016-11-22 16:58:57 +01:00
parent e4ed3a3a74
commit 6a85a98822
2 changed files with 84 additions and 11 deletions
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55
nova/tests/unit/virt/libvirt/test_migration.py
View File

@ -79,6 +79,17 @@ class UtilityMigrationTestCase(test.NoDBTestCase):
addr = migration.serial_listen_addr(data)
self.assertIsNone(addr)
def test_serial_listen_ports(self):
data = objects.LibvirtLiveMigrateData(
serial_listen_ports=[1, 2, 3])
ports = migration.serial_listen_ports(data)
self.assertEqual([1, 2, 3], ports)
def test_serial_listen_ports_emtpy(self):
data = objects.LibvirtLiveMigrateData()
ports = migration.serial_listen_ports(data)
self.assertEqual([], ports)
@mock.patch('lxml.etree.tostring')
@mock.patch.object(migration, '_update_perf_events_xml')
@mock.patch.object(migration, '_update_graphics_xml')
@ -101,26 +112,60 @@ class UtilityMigrationTestCase(test.NoDBTestCase):
def test_update_serial_xml_serial(self):
data = objects.LibvirtLiveMigrateData(
serial_listen_addr='127.0.0.100')
serial_listen_addr='127.0.0.100',
serial_listen_ports=[2001])
xml = """<domain>
<devices>
<serial type="tcp">
<source host="127.0.0.1"/>
<source host="127.0.0.1" service="2000"/>
<target type="serial" port="0"/>
</serial>
</devices>
</domain>"""
doc = etree.fromstring(xml)
res = etree.tostring(migration._update_serial_xml(doc, data))
new_xml = xml.replace("127.0.0.1", "127.0.0.100")
new_xml = xml.replace("127.0.0.1", "127.0.0.100").replace(
"2000", "2001")
self.assertThat(res, matchers.XMLMatches(new_xml))
def test_update_serial_xml_console(self):
data = objects.LibvirtLiveMigrateData(
serial_listen_addr='127.0.0.100')
serial_listen_addr='127.0.0.100',
serial_listen_ports=[299, 300])
xml = """<domain>
<devices>
<console type="tcp">
<source host="127.0.0.1"/>
<source host="127.0.0.1" service="2001"/>
<target type="serial" port="0"/>
</console>
<console type="tcp">
<source host="127.0.0.1" service="2002"/>
<target type="serial" port="1"/>
</console>
</devices>
</domain>"""
doc = etree.fromstring(xml)
res = etree.tostring(migration._update_serial_xml(doc, data))
new_xml = xml.replace("127.0.0.1", "127.0.0.100").replace(
"2001", "299").replace("2002", "300")
self.assertThat(res, matchers.XMLMatches(new_xml))
def test_update_serial_xml_without_ports(self):
# This test is for backwards compatibility when we don't
# get the serial ports from the target node.
data = objects.LibvirtLiveMigrateData(
serial_listen_addr='127.0.0.100',
serial_listen_ports=[])
xml = """<domain>
<devices>
<console type="tcp">
<source host="127.0.0.1" service="2001"/>
<target type="serial" port="0"/>
</console>
<console type="tcp">
<source host="127.0.0.1" service="2002"/>
<target type="serial" port="1"/>
</console>
</devices>
</domain>"""

40
nova/virt/libvirt/migration.py
View File

@ -65,6 +65,15 @@ def serial_listen_addr(migrate_data):
return listen_addr
# TODO(sahid): remove me for Q*
def serial_listen_ports(migrate_data):
"""Returns ports serial from a LibvirtLiveMigrateData"""
ports = []
if migrate_data.obj_attr_is_set('serial_listen_ports'):
ports = migrate_data.serial_listen_ports
return ports
def get_updated_guest_xml(guest, migrate_data, get_volume_config):
xml_doc = etree.fromstring(guest.get_xml_desc(dump_migratable=True))
xml_doc = _update_graphics_xml(xml_doc, migrate_data)
@ -91,12 +100,31 @@ def _update_graphics_xml(xml_doc, migrate_data):
def _update_serial_xml(xml_doc, migrate_data):
listen_addr = serial_listen_addr(migrate_data)
for dev in xml_doc.findall("./devices/serial[@type='tcp']/source"):
if dev.get('host') is not None:
dev.set('host', listen_addr)
for dev in xml_doc.findall("./devices/console[@type='tcp']/source"):
if dev.get('host') is not None:
dev.set('host', listen_addr)
listen_ports = serial_listen_ports(migrate_data)
def set_listen_addr_and_port(source, listen_addr, serial_listen_ports):
# The XML nodes can be empty, which would make checks like
# "if source.get('host'):" different to an explicit check for
# None. That's why we have to check for None in this method.
if source.get('host') is not None:
source.set('host', listen_addr)
device = source.getparent()
target = device.find("target")
if target is not None and source.get('service') is not None:
port_index = int(target.get('port'))
# NOTE (markus_z): Previous releases might not give us the
# ports yet, that's why we have this check here.
if len(serial_listen_ports) > port_index:
source.set('service', str(serial_listen_ports[port_index]))
# This updates all "LibvirtConfigGuestSerial" devices
for source in xml_doc.findall("./devices/serial[@type='tcp']/source"):
set_listen_addr_and_port(source, listen_addr, listen_ports)
# This updates all "LibvirtConfigGuestConsole" devices
for source in xml_doc.findall("./devices/console[@type='tcp']/source"):
set_listen_addr_and_port(source, listen_addr, listen_ports)
return xml_doc