This branch adds support for linux containers (LXC) to nova. It uses the libvirt LXC driver to start and stop the instance.

4 files changed, 120 insertions, 12 deletions

diff --git a/nova/tests/test_virt.py b/nova/tests/test_virt.py
index 3a03159ff..958c8e3e2 100644
--- a/nova/tests/test_virt.py
+++ b/nova/tests/test_virt.py
@@ -225,6 +225,49 @@ class LibvirtConnTestCase(test.TestCase):
         self._check_xml_and_uri(instance_data, expect_kernel=True,
                                 expect_ramdisk=True, rescue=True)
 
+    def test_lxc_container_and_uri(self):
+        instance_data = dict(self.test_instance)
+        self._check_xml_and_container(instance_data)
+
+    def _check_xml_and_container(self, instance):
+        user_context = context.RequestContext(project=self.project,
+                                              user=self.user)
+        instance_ref = db.instance_create(user_context, instance)
+        host = self.network.get_network_host(user_context.elevated())
+        network_ref = db.project_get_network(context.get_admin_context(),
+                                             self.project.id)
+
+        fixed_ip = {'address': self.test_ip,
+                    'network_id': network_ref['id']}
+
+        ctxt = context.get_admin_context()
+        fixed_ip_ref = db.fixed_ip_create(ctxt, fixed_ip)
+        db.fixed_ip_update(ctxt, self.test_ip,
+                                 {'allocated': True,
+                                  'instance_id': instance_ref['id']})
+
+        self.flags(libvirt_type='lxc')
+        conn = libvirt_conn.LibvirtConnection(True)
+
+        uri = conn.get_uri()
+        self.assertEquals(uri, 'lxc:///')
+
+        xml = conn.to_xml(instance_ref)
+        tree = xml_to_tree(xml)
+
+        check = [
+        (lambda t: t.find('.').get('type'), 'lxc'),
+        (lambda t: t.find('./os/type').text, 'exe'),
+        (lambda t: t.find('./devices/filesystem/target').get('dir'), '/')]
+
+        for i, (check, expected_result) in enumerate(check):
+            self.assertEqual(check(tree),
+                             expected_result,
+                             '%s failed common check %d' % (xml, i))
+
+        target = tree.find('./devices/filesystem/source').get('dir')
+        self.assertTrue(len(target) > 0)
+
     def _check_xml_and_uri(self, instance, expect_ramdisk, expect_kernel,
                            rescue=False):
         user_context = context.RequestContext(project=self.project,
diff --git a/nova/virt/disk.py b/nova/virt/disk.py
index 25e4f54a9..ddea1a1f7 100644
--- a/nova/virt/disk.py
+++ b/nova/virt/disk.py
@@ -116,6 +116,41 @@ def inject_data(image, key=None, net=None, partition=None, nbd=False):
         _unlink_device(device, nbd)
 
 
+def setup_container(image, container_dir=None, nbd=False):
+    """Setup the LXC container.
+
+    It will mount the loopback image to the container directory in order
+    to create the root filesystem for the container.
+
+    LXC does not support qcow2 images yet.
+    """
+    try:
+        device = _link_device(image, nbd)
+        utils.execute('sudo', 'mount', device, container_dir)
+    except Exception, exn:
+        LOG.exception(_('Failed to mount filesystem: %s'), exn)
+        _unlink_device(device, nbd)
+
+
+def destroy_container(target, instance, nbd=False):
+    """Destroy the container once it terminates.
+
+    It will umount the container that is mounted, try to find the loopback
+    device associated with the container and delete it.
+
+    LXC does not support qcow2 images yet.
+    """
+    try:
+        container_dir = '%s/rootfs' % target
+        utils.execute('sudo', 'umount', container_dir)
+    finally:
+        out, err = utils.execute('sudo', 'losetup', '-a')
+        for loop in out.splitlines():
+            if instance['name'] in loop:
+                device = loop.split(loop, ':')
+                _unlink_device(device, nbd)
+
+
 def _link_device(image, nbd):
     """Link image to device using loopback or nbd"""
     if nbd:
diff --git a/nova/virt/libvirt.xml.template b/nova/virt/libvirt.xml.template
index d74a9e85b..36d18ed95 100644
--- a/nova/virt/libvirt.xml.template
+++ b/nova/virt/libvirt.xml.template
@@ -2,7 +2,12 @@
     <name>${name}</name>
     <memory>${memory_kb}</memory>
     <os>
-#if $type == 'uml'
+#if $type == 'lxc'
+    #set $disk_prefix = ''
+    #set $disk_bus = ''
+        <type>exe</type>
+        <init>/sbin/init</init>
+#else if $type == 'uml'
     #set $disk_prefix = 'ubd'
     #set $disk_bus = 'uml'
         <type>uml</type>
@@ -44,7 +49,13 @@
     </features>
     <vcpu>${vcpus}</vcpu>
     <devices>
-#if $getVar('rescue', False)
+#if $type == 'lxc'
+        <filesystem type='mount'>
+            <source dir='${basepath}/rootfs'/>
+            <target dir='/'/>
+        </filesystem>
+#else
+    #if $getVar('rescue', False)
         <disk type='file'>
             <driver type='${driver_type}'/>
             <source file='${basepath}/disk.rescue'/>
@@ -55,18 +66,19 @@
             <source file='${basepath}/disk'/>
             <target dev='${disk_prefix}b' bus='${disk_bus}'/>
         </disk>
-#else
+    #else
         <disk type='file'>
             <driver type='${driver_type}'/>
             <source file='${basepath}/disk'/>
             <target dev='${disk_prefix}a' bus='${disk_bus}'/>
         </disk>
-    #if $getVar('local', False)
-        <disk type='file'>
-            <driver type='${driver_type}'/>
-            <source file='${basepath}/disk.local'/>
-            <target dev='${disk_prefix}b' bus='${disk_bus}'/>
-        </disk>
+        #if $getVar('local', False)
+            <disk type='file'>
+                <driver type='${driver_type}'/>
+                <source file='${basepath}/disk.local'/>
+                <target dev='${disk_prefix}b' bus='${disk_bus}'/>
+            </disk>
+        #end if
     #end if
 #end if
 
@@ -87,7 +99,6 @@
             </filterref>
         </interface>
 #end for
-
         <!-- The order is significant here.  File must be defined first -->
         <serial type="file">
             <source path='${basepath}/console.log'/>
diff --git a/nova/virt/libvirt_conn.py b/nova/virt/libvirt_conn.py
index 80eb64f3c..ae3a967a4 100644
--- a/nova/virt/libvirt_conn.py
+++ b/nova/virt/libvirt_conn.py
@@ -20,7 +20,7 @@
 """
 A connection to a hypervisor through libvirt.
 
-Supports KVM, QEMU, UML, and XEN.
+Supports KVM, LXC, QEMU, UML, and XEN.
 
 **Related Flags**
 
@@ -86,7 +86,7 @@ flags.DEFINE_string('libvirt_xml_template',
 flags.DEFINE_string('libvirt_type',
                     'kvm',
                     'Libvirt domain type (valid options are: '
-                    'kvm, qemu, uml, xen)')
+                    'kvm, lxc, qemu, uml, xen)')
 flags.DEFINE_string('libvirt_uri',
                     '',
                     'Override the default libvirt URI (which is dependent'
@@ -266,6 +266,8 @@ class LibvirtConnection(driver.ComputeDriver):
             uri = FLAGS.libvirt_uri or 'uml:///system'
         elif FLAGS.libvirt_type == 'xen':
             uri = FLAGS.libvirt_uri or 'xen:///'
+        elif FLAGS.libvirt_type == 'lxc':
+            uri = FLAGS.libvirt_uri or 'lxc:///'
         else:
             uri = FLAGS.libvirt_uri or 'qemu:///system'
         return uri
@@ -344,6 +346,8 @@ class LibvirtConnection(driver.ComputeDriver):
         instance_name = instance['name']
         LOG.info(_('instance %(instance_name)s: deleting instance files'
                 ' %(target)s') % locals())
+        if FLAGS.libvirt_type == 'lxc':
+            disk.destroy_container(target, instance, nbd=FLAGS.use_cow_images)
         if os.path.exists(target):
             shutil.rmtree(target)
 
@@ -625,6 +629,9 @@ class LibvirtConnection(driver.ComputeDriver):
                                          instance['name'])
             data = self._flush_xen_console(virsh_output)
             fpath = self._append_to_file(data, console_log)
+        elif FLAGS.libvirt_type == 'lxc':
+            # LXC is also special
+            LOG.info(_("Unable to read LXC console"))
         else:
             fpath = console_log
 
@@ -738,6 +745,10 @@ class LibvirtConnection(driver.ComputeDriver):
         f.write(libvirt_xml)
         f.close()
 
+        if FLAGS.libvirt_type == 'lxc':
+            container_dir = '%s/rootfs' % basepath(suffix='')
+            utils.execute('mkdir', '-p', container_dir)
+
         # NOTE(vish): No need add the suffix to console.log
         os.close(os.open(basepath('console.log', ''),
                          os.O_CREAT | os.O_WRONLY, 0660))
@@ -797,6 +808,9 @@ class LibvirtConnection(driver.ComputeDriver):
         if not inst['kernel_id']:
             target_partition = "1"
 
+        if FLAGS.libvirt_type == 'lxc':
+            target_partition = None
+
         key = str(inst['key_data'])
         net = None
 
@@ -842,6 +856,11 @@ class LibvirtConnection(driver.ComputeDriver):
                 disk.inject_data(basepath('disk'), key, net,
                                  partition=target_partition,
                                  nbd=FLAGS.use_cow_images)
+
+                if FLAGS.libvirt_type == 'lxc':
+                    disk.setup_container(basepath('disk'),
+                                        container_dir=container_dir,
+                                        nbd=FLAGS.use_cow_images)
             except Exception as e:
                 # This could be a windows image, or a vmdk format disk
                 LOG.warn(_('instance %(inst_name)s: ignoring error injecting'