# 'pool_timeout' is the maximum number of seconds to wait when retrieving a
# new connection from the pool. After the specified amount of time, an
# exception will be thrown.
pool_timeout=30,  # 30 seconds
# 'pool_recycle' is the maximum number of seconds a connection can persist.
# Connections that live longer than the specified amount of time will be
# re-established
pool_recycle=1800,  # 30 minutes
# Pool size is the maximum number of permanent connections to keep.
pool_size=5,
# Temporarily exceeds the set pool_size if no connections are available.
max_overflow=2,
# The total number of concurrent connections for your application will be
# a total of pool_size and max_overflow.

nova.api.openstack.compute.servers.ServersController
def _action_reboot(self, req, id, body):

        reboot_type = body['reboot']['type'].upper()
        context = req.environ['nova.context']
        context.can(server_policies.SERVERS % 'reboot')
        instance = self._get_server(context, req, id)

        try:
            self.compute_api.reboot(context, instance, reboot_type)
            .................................................
            
 nova.compute.api.API
  @check_instance_lock
  def reboot(self, context, instance, reboot_type):
        """Reboot the given instance."""
        if reboot_type == 'SOFT':
            self._soft_reboot(context, instance)
        else:
            self._hard_reboot(context, instance)

cinder.volume.manager.VolumeManager.initialize_connection
def initialize_connection(self, context, volume, connector):
   ...............................................
        try:
            conn_info = self.driver.initialize_connection(volume, connector)
        except Exception as err:
            err_msg = (_("Driver initialize connection failed "
                         "(error: %(err)s).") % {'err': six.text_type(err)})
            LOG.exception(err_msg, resource=volume)

            self.driver.remove_export(context.elevated(), volume)

            raise exception.VolumeBackendAPIException(data=err_msg)

        conn_info = self._parse_connection_options(context, volume, conn_info)
        LOG.info("Initialize volume connection completed successfully.",
                 resource=volume)
        return conn_info

def _parse_connection_options(self, context, volume, conn_info):
       # Add qos_specs to connection info
       typeid = volume.volume_type_id
       specs = None
       if typeid:
           res = volume_types.get_volume_type_qos_specs(typeid)
           qos = res['qos_specs']
           # only pass qos_specs that is designated to be consumed by
           # front-end, or both front-end and back-end.
           if qos and qos.get('consumer') in ['front-end', 'both']:
               specs = qos.get('specs')

           # NOTE(mnaser): The following configures for per-GB QoS
           if specs is not None:
               volume_size = int(volume.size)
               tune_opts = ('read_iops_sec', 'read_bytes_sec',
                            'write_iops_sec', 'write_bytes_sec',
                            'total_iops_sec', 'total_bytes_sec')

               for option in tune_opts:
                   option_per_gb = '%s_per_gb' % option
                   option_per_gb_min = '%s_per_gb_min' % option
                   option_max = '%s_max' % option
                   option_base = '%s_base' % option
                   if option_per_gb in specs:
                       minimum_value = int(specs.pop(option_per_gb_min, 0))
                       value = int(specs[option_per_gb]) * volume_size
                       per_gb_value = max(minimum_value, value)
                       base_value = int(specs.pop(option_base, 0))
                       final_value = base_value + per_gb_value
                       max_value = int(specs.pop(option_max, final_value))
                       specs[option] = min(final_value, max_value)
                       specs.pop(option_per_gb)

       qos_spec = dict(qos_specs=specs)
       conn_info['data'].update(qos_spec)
       ...............................................

nova.compute.manager.ComputeManager._attach_volume:
    try:
            bdm.attach(context, instance, self.volume_api, self.driver,
                       do_driver_attach=True)
    ......................................
    

cinder.scheduler.manager.SchedulerManager.create_volume
        try:
            flow_engine = create_volume.get_flow(context,
                                                 self.driver,
                                                 request_spec,
                                                 filter_properties,
                                                 volume,
                                                 snapshot_id,
                                                 image_id,
                                                 backup_id)
        except Exception:
            msg = _("Failed to create scheduler manager volume flow")
            LOG.exception(msg)
            raise exception.CinderException(msg)

显示主机已有网桥以及端口port信息,以及vxlan隧道信息
#ovs-vsctl show

添加网桥
#ovs-vsctl add-br br-test

输出交换机信息，输出交换机上的网卡以及端口port信息
#ovs-ofctl show br-int

输出交换机的端口统计信息，包括收发包、丢包、错误包等数量
#ovs-ofctl dump-ports br-int -O openFlow13

查看交换机流表信息
#ovs-ofctl dump-flows br-int

添加交换机流表
#ovs-ofctl add-flow br-int ********

显示所有datapath基本信息
#ovs-dpctl show

查询虚机mac fa:16:3e:ac:21:48 到 虚机 fa:16:3e:b0:bf:cc的流表trace路径
#ovs-appctl ofproto/trace br-int in_port=27,dl_src=fa:16:3e:ac:21:48,dl_dst=fa:16:3e:b0:bf:cc

1. 查询虚机test01 (tapa6df2bfb-e5)的 port id以及mac 
   #ovs-ofctl show br-int -O openFlow13|grep tapa6df2bfb-e5  #查出是8号，mac     fa:16:3e:f6:b8:81
2. 查询虚机test02 (tapf9689b0e-e4)的 port id
   #ovs-ofctl show br-int -O openFlow13|grep tapf9689b0e-e4  查出是13号，mac是fa:16:3e:5a:35:74
3. 查询虚机test01到test02的icmp流表路径
#docker exec -it -uroot openvswitch_vswitchd bash
#ovs-appctl ofproto/trace br-int in_port=8,dl_src=fa:16:3e:f6:b8:81,dl_dst=fa:16:3e:5a:35:74

如果能在br-tun上送到 kernel tunnel代表正常

#nova/conductor/manager.py #
def build_instances(self, context, instances, image, filter_properties,
            admin_password, injected_files, requested_networks,
            security_groups, block_device_mapping=None, legacy_bdm=True,
            request_spec=None, host_lists=None):
            .......................
            self.compute_rpcapi.build_and_run_instance(context,
                                instance=instance, host=host.service_host, image=image,
                                request_spec=local_reqspec,
                                filter_properties=local_filter_props,
                                admin_password=admin_password,
                                injected_files=injected_files,
                                requested_networks=requested_networks,
                                security_groups=security_groups,
                                block_device_mapping=bdms, node=host.nodename,
                                limits=host.limits, host_list=host_list)

def build_and_run_instance(self, ctxt, instance, host, image, request_spec,
            filter_properties, admin_password=None, injected_files=None,
            requested_networks=None, security_groups=None,
            block_device_mapping=None, node=None, limits=None,
            host_list=None):
            .........
            cctxt.cast(ctxt, 'build_and_run_instance', **kwargs)