Adds diagnostics command for the libvirt driver.

This code provides an implementation of the get_diagnostics
API for the libvirt driver. This API is invoked by the
'nova diagnostic' command.

There is no existing formal specification for what data items
to expose from the 'get_diagnostics' API, so the XenAPI driver
is used as an informal guide. The Xen implementation currently
produces the following output:

+----------------+-----------------+
|    Property    |      Value      |
+----------------+-----------------+
| cpu0           | 4.3627          |
| memory         | 1171088064.0000 |
| memory_target  | 1171088064.0000 |
| vbd_xvda_read  | 0.0             |
| vbd_xvda_write | 0.0             |
| vif_0_rx       | 3223.6870       |
| vif_0_tx       | 0.0             |
| vif_1_rx       | 104.4955        |
| vif_1_tx       | 0.0             |
+----------------+-----------------+

The new libvirt implementation will return a similar set of stats
for guest CPUs, memory, disks and network interfaces, resulting
in the following output:

+------------------+------------+
| Property         | Value      |
+------------------+------------+
| cpu0_time        | 2870000000 |
| memory           | 524288     |
| vda_errors       | -1         |
| vda_read         | 262144     |
| vda_read_req     | 112        |
| vda_write        | 5606400    |
| vda_write_req    | 376        |
| vnet0_rx         | 63343      |
| vnet0_rx_drop    | 0          |
| vnet0_rx_errors  | 0          |
| vnet0_rx_packets | 431        |
| vnet0_tx         | 4905       |
| vnet0_tx_drop    | 0          |
| vnet0_tx_errors  | 0          |
| vnet0_tx_packets | 45         |
+------------------+------------+

The implementation has only been tested with the libvirt KVM
driver.

In a future a formal specification for the required data
format should be written and all virt drivers made to comply.

Finally, the fakelibvirt driver has been updated in order to
support the methods required by the get_diagnostics method.

For those interested, below is the formula to extract the
CPU usage based on the CPU time. I've added it here for reference
since it's not used at the moment and it took quite a while
to locate it in the libvirt documentation.

  usage = 100 * (current_cpu_time - last_cpu_time) /
          (measurement_interval * (10 ** 9))

Fixes bug 986200.
Change-Id: I92da392f43d0840ed31cfd88f54570ea5830bb4a

nova/tests/fakelibvirt.py

@@ -424,6 +424,19 @@ class Domain(object):
         self._snapshots[name] = snapshot
         return snapshot
 
+    def vcpus(self):
+        vcpus = ([], [])
+        for i in range(0, self._def['vcpu']):
+            vcpus[0].append((i, 1, 120405L, i))
+            vcpus[1].append((True, True, True, True))
+        return vcpus
+
+    def memoryStats(self):
+        return {}
+
+    def maxMemory(self):
+        return self._def['memory']
+
 
 class DomainSnapshot(object):
     def __init__(self, name, domain):

nova/tests/test_libvirt.py

@@ -1,6 +1,7 @@
 # vim: tabstop=4 shiftwidth=4 softtabstop=4
 #
 #    Copyright 2010 OpenStack LLC
+#    Copyright 2012 University Of Minho
 #
 #    Licensed under the Apache License, Version 2.0 (the "License"); you may
 #    not use this file except in compliance with the License. You may obtain
@@ -1919,6 +1920,395 @@ class LibvirtConnTestCase(test.TestCase):
         got = jsonutils.loads(conn.get_cpu_info())
         self.assertEqual(want, got)
 
+    def test_diagnostic_vcpus_exception(self):
+        xml = """
+                <domain type='kvm'>
+                    <devices>
+                        <disk type='file'>
+                            <source file='filename'/>
+                            <target dev='vda' bus='virtio'/>
+                        </disk>
+                        <disk type='block'>
+                            <source dev='/path/to/dev/1'/>
+                            <target dev='vdb' bus='virtio'/>
+                        </disk>
+                        <interface type='network'>
+                            <mac address='52:54:00:a4:38:38'/>
+                            <source network='default'/>
+                            <target dev='vnet0'/>
+                        </interface>
+                    </devices>
+                </domain>
+            """
+
+        class DiagFakeDomain(FakeVirtDomain):
+
+            def __init__(self):
+                super(DiagFakeDomain, self).__init__(fake_xml=xml)
+
+            def vcpus(self):
+                raise libvirt.libvirtError('vcpus missing')
+
+            def blockStats(self, path):
+                return (169L, 688640L, 0L, 0L, -1L)
+
+            def interfaceStats(self, path):
+                return (4408L, 82L, 0L, 0L, 0L, 0L, 0L, 0L)
+
+            def memoryStats(self):
+                return {'actual': 220160L, 'rss': 200164L}
+
+            def maxMemory(self):
+                return 280160L
+
+        def fake_lookup_name(name):
+            return DiagFakeDomain()
+
+        self.mox.StubOutWithMock(libvirt_driver.LibvirtDriver, '_conn')
+        libvirt_driver.LibvirtDriver._conn.lookupByName = fake_lookup_name
+
+        conn = libvirt_driver.LibvirtDriver(False)
+        actual = conn.get_diagnostics({"name": "testvirt"})
+        expect = {'vda_read': 688640L,
+                  'vda_read_req': 169L,
+                  'vda_write': 0L,
+                  'vda_write_req': 0L,
+                  'vda_errors': -1L,
+                  'vdb_read': 688640L,
+                  'vdb_read_req': 169L,
+                  'vdb_write': 0L,
+                  'vdb_write_req': 0L,
+                  'vdb_errors': -1L,
+                  'memory': 280160L,
+                  'memory-actual': 220160L,
+                  'memory-rss': 200164L,
+                  'vnet0_rx': 4408L,
+                  'vnet0_rx_drop': 0L,
+                  'vnet0_rx_errors': 0L,
+                  'vnet0_rx_packets': 82L,
+                  'vnet0_tx': 0L,
+                  'vnet0_tx_drop': 0L,
+                  'vnet0_tx_errors': 0L,
+                  'vnet0_tx_packets': 0L,
+                  }
+        self.assertEqual(actual, expect)
+
+    def test_diagnostic_blockstats_exception(self):
+        xml = """
+                <domain type='kvm'>
+                    <devices>
+                        <disk type='file'>
+                            <source file='filename'/>
+                            <target dev='vda' bus='virtio'/>
+                        </disk>
+                        <disk type='block'>
+                            <source dev='/path/to/dev/1'/>
+                            <target dev='vdb' bus='virtio'/>
+                        </disk>
+                        <interface type='network'>
+                            <mac address='52:54:00:a4:38:38'/>
+                            <source network='default'/>
+                            <target dev='vnet0'/>
+                        </interface>
+                    </devices>
+                </domain>
+            """
+
+        class DiagFakeDomain(FakeVirtDomain):
+
+            def __init__(self):
+                super(DiagFakeDomain, self).__init__(fake_xml=xml)
+
+            def vcpus(self):
+                return ([(0, 1, 15340000000L, 0),
+                         (1, 1, 1640000000L, 0),
+                         (2, 1, 3040000000L, 0),
+                         (3, 1, 1420000000L, 0)],
+                        [(True, False),
+                         (True, False),
+                         (True, False),
+                         (True, False)])
+
+            def blockStats(self, path):
+                raise libvirt.libvirtError('blockStats missing')
+
+            def interfaceStats(self, path):
+                return (4408L, 82L, 0L, 0L, 0L, 0L, 0L, 0L)
+
+            def memoryStats(self):
+                return {'actual': 220160L, 'rss': 200164L}
+
+            def maxMemory(self):
+                return 280160L
+
+        def fake_lookup_name(name):
+            return DiagFakeDomain()
+
+        self.mox.StubOutWithMock(libvirt_driver.LibvirtDriver, '_conn')
+        libvirt_driver.LibvirtDriver._conn.lookupByName = fake_lookup_name
+
+        conn = libvirt_driver.LibvirtDriver(False)
+        actual = conn.get_diagnostics({"name": "testvirt"})
+        expect = {'cpu0_time': 15340000000L,
+                  'cpu1_time': 1640000000L,
+                  'cpu2_time': 3040000000L,
+                  'cpu3_time': 1420000000L,
+                  'memory': 280160L,
+                  'memory-actual': 220160L,
+                  'memory-rss': 200164L,
+                  'vnet0_rx': 4408L,
+                  'vnet0_rx_drop': 0L,
+                  'vnet0_rx_errors': 0L,
+                  'vnet0_rx_packets': 82L,
+                  'vnet0_tx': 0L,
+                  'vnet0_tx_drop': 0L,
+                  'vnet0_tx_errors': 0L,
+                  'vnet0_tx_packets': 0L,
+                  }
+        self.assertEqual(actual, expect)
+
+    def test_diagnostic_interfacestats_exception(self):
+        xml = """
+                <domain type='kvm'>
+                    <devices>
+                        <disk type='file'>
+                            <source file='filename'/>
+                            <target dev='vda' bus='virtio'/>
+                        </disk>
+                        <disk type='block'>
+                            <source dev='/path/to/dev/1'/>
+                            <target dev='vdb' bus='virtio'/>
+                        </disk>
+                        <interface type='network'>
+                            <mac address='52:54:00:a4:38:38'/>
+                            <source network='default'/>
+                            <target dev='vnet0'/>
+                        </interface>
+                    </devices>
+                </domain>
+            """
+
+        class DiagFakeDomain(FakeVirtDomain):
+
+            def __init__(self):
+                super(DiagFakeDomain, self).__init__(fake_xml=xml)
+
+            def vcpus(self):
+                return ([(0, 1, 15340000000L, 0),
+                         (1, 1, 1640000000L, 0),
+                         (2, 1, 3040000000L, 0),
+                         (3, 1, 1420000000L, 0)],
+                        [(True, False),
+                         (True, False),
+                         (True, False),
+                         (True, False)])
+
+            def blockStats(self, path):
+                return (169L, 688640L, 0L, 0L, -1L)
+
+            def interfaceStats(self, path):
+                raise libvirt.libvirtError('interfaceStat missing')
+
+            def memoryStats(self):
+                return {'actual': 220160L, 'rss': 200164L}
+
+            def maxMemory(self):
+                return 280160L
+
+        def fake_lookup_name(name):
+            return DiagFakeDomain()
+
+        self.mox.StubOutWithMock(libvirt_driver.LibvirtDriver, '_conn')
+        libvirt_driver.LibvirtDriver._conn.lookupByName = fake_lookup_name
+
+        conn = libvirt_driver.LibvirtDriver(False)
+        actual = conn.get_diagnostics({"name": "testvirt"})
+        expect = {'cpu0_time': 15340000000L,
+                  'cpu1_time': 1640000000L,
+                  'cpu2_time': 3040000000L,
+                  'cpu3_time': 1420000000L,
+                  'vda_read': 688640L,
+                  'vda_read_req': 169L,
+                  'vda_write': 0L,
+                  'vda_write_req': 0L,
+                  'vda_errors': -1L,
+                  'vdb_read': 688640L,
+                  'vdb_read_req': 169L,
+                  'vdb_write': 0L,
+                  'vdb_write_req': 0L,
+                  'vdb_errors': -1L,
+                  'memory': 280160L,
+                  'memory-actual': 220160L,
+                  'memory-rss': 200164L,
+                  }
+        self.assertEqual(actual, expect)
+
+    def test_diagnostic_memorystats_exception(self):
+        xml = """
+                <domain type='kvm'>
+                    <devices>
+                        <disk type='file'>
+                            <source file='filename'/>
+                            <target dev='vda' bus='virtio'/>
+                        </disk>
+                        <disk type='block'>
+                            <source dev='/path/to/dev/1'/>
+                            <target dev='vdb' bus='virtio'/>
+                        </disk>
+                        <interface type='network'>
+                            <mac address='52:54:00:a4:38:38'/>
+                            <source network='default'/>
+                            <target dev='vnet0'/>
+                        </interface>
+                    </devices>
+                </domain>
+            """
+
+        class DiagFakeDomain(FakeVirtDomain):
+
+            def __init__(self):
+                super(DiagFakeDomain, self).__init__(fake_xml=xml)
+
+            def vcpus(self):
+                return ([(0, 1, 15340000000L, 0),
+                         (1, 1, 1640000000L, 0),
+                         (2, 1, 3040000000L, 0),
+                         (3, 1, 1420000000L, 0)],
+                        [(True, False),
+                         (True, False),
+                         (True, False),
+                         (True, False)])
+
+            def blockStats(self, path):
+                return (169L, 688640L, 0L, 0L, -1L)
+
+            def interfaceStats(self, path):
+                return (4408L, 82L, 0L, 0L, 0L, 0L, 0L, 0L)
+
+            def memoryStats(self):
+                raise libvirt.libvirtError('memoryStats missing')
+
+            def maxMemory(self):
+                return 280160L
+
+        def fake_lookup_name(name):
+            return DiagFakeDomain()
+
+        self.mox.StubOutWithMock(libvirt_driver.LibvirtDriver, '_conn')
+        libvirt_driver.LibvirtDriver._conn.lookupByName = fake_lookup_name
+
+        conn = libvirt_driver.LibvirtDriver(False)
+        actual = conn.get_diagnostics({"name": "testvirt"})
+        expect = {'cpu0_time': 15340000000L,
+                  'cpu1_time': 1640000000L,
+                  'cpu2_time': 3040000000L,
+                  'cpu3_time': 1420000000L,
+                  'vda_read': 688640L,
+                  'vda_read_req': 169L,
+                  'vda_write': 0L,
+                  'vda_write_req': 0L,
+                  'vda_errors': -1L,
+                  'vdb_read': 688640L,
+                  'vdb_read_req': 169L,
+                  'vdb_write': 0L,
+                  'vdb_write_req': 0L,
+                  'vdb_errors': -1L,
+                  'memory': 280160L,
+                  'vnet0_rx': 4408L,
+                  'vnet0_rx_drop': 0L,
+                  'vnet0_rx_errors': 0L,
+                  'vnet0_rx_packets': 82L,
+                  'vnet0_tx': 0L,
+                  'vnet0_tx_drop': 0L,
+                  'vnet0_tx_errors': 0L,
+                  'vnet0_tx_packets': 0L,
+                  }
+        self.assertEqual(actual, expect)
+
+    def test_diagnostic_full(self):
+        xml = """
+                <domain type='kvm'>
+                    <devices>
+                        <disk type='file'>
+                            <source file='filename'/>
+                            <target dev='vda' bus='virtio'/>
+                        </disk>
+                        <disk type='block'>
+                            <source dev='/path/to/dev/1'/>
+                            <target dev='vdb' bus='virtio'/>
+                        </disk>
+                        <interface type='network'>
+                            <mac address='52:54:00:a4:38:38'/>
+                            <source network='default'/>
+                            <target dev='vnet0'/>
+                        </interface>
+                    </devices>
+                </domain>
+            """
+
+        class DiagFakeDomain(FakeVirtDomain):
+
+            def __init__(self):
+                super(DiagFakeDomain, self).__init__(fake_xml=xml)
+
+            def vcpus(self):
+                return ([(0, 1, 15340000000L, 0),
+                         (1, 1, 1640000000L, 0),
+                         (2, 1, 3040000000L, 0),
+                         (3, 1, 1420000000L, 0)],
+                        [(True, False),
+                         (True, False),
+                         (True, False),
+                         (True, False)])
+
+            def blockStats(self, path):
+                return (169L, 688640L, 0L, 0L, -1L)
+
+            def interfaceStats(self, path):
+                return (4408L, 82L, 0L, 0L, 0L, 0L, 0L, 0L)
+
+            def memoryStats(self):
+                return {'actual': 220160L, 'rss': 200164L}
+
+            def maxMemory(self):
+                return 280160L
+
+        def fake_lookup_name(name):
+            return DiagFakeDomain()
+
+        self.mox.StubOutWithMock(libvirt_driver.LibvirtDriver, '_conn')
+        libvirt_driver.LibvirtDriver._conn.lookupByName = fake_lookup_name
+
+        conn = libvirt_driver.LibvirtDriver(False)
+        actual = conn.get_diagnostics({"name": "testvirt"})
+        expect = {'cpu0_time': 15340000000L,
+                  'cpu1_time': 1640000000L,
+                  'cpu2_time': 3040000000L,
+                  'cpu3_time': 1420000000L,
+                  'vda_read': 688640L,
+                  'vda_read_req': 169L,
+                  'vda_write': 0L,
+                  'vda_write_req': 0L,
+                  'vda_errors': -1L,
+                  'vdb_read': 688640L,
+                  'vdb_read_req': 169L,
+                  'vdb_write': 0L,
+                  'vdb_write_req': 0L,
+                  'vdb_errors': -1L,
+                  'memory': 280160L,
+                  'memory-actual': 220160L,
+                  'memory-rss': 200164L,
+                  'vnet0_rx': 4408L,
+                  'vnet0_rx_drop': 0L,
+                  'vnet0_rx_errors': 0L,
+                  'vnet0_rx_packets': 82L,
+                  'vnet0_tx': 0L,
+                  'vnet0_tx_drop': 0L,
+                  'vnet0_tx_errors': 0L,
+                  'vnet0_tx_packets': 0L,
+                  }
+        self.assertEqual(actual, expect)
+
 
 class HostStateTestCase(test.TestCase):
 

nova/tests/test_virt_drivers.py

@@ -402,7 +402,7 @@ class _VirtDriverTestCase(_FakeDriverBackendTestCase):
     @catch_notimplementederror
     def test_get_diagnostics(self):
         instance_ref, network_info = self._get_running_instance()
-        self.connection.get_diagnostics(instance_ref['name'])
+        self.connection.get_diagnostics(instance_ref)
 
     @catch_notimplementederror
     def test_block_stats(self):