In Vlan mode can't create a network when --vlan option is not set

[Haiwei Xu]

In Vlan mode when I tried to create a network without setting the --vlan mode, I got the DuplicateVlan exception.

$ nova network-create --fixed-range-v4 192.168.3.1/24 net

ERROR: The server has either erred or is incapable of performing the requested operation. (HTTP 500) (Request-ID: req-14c6c520-d6a4-4d6e-9280-3957091f4631)

The log in the nova-network service is :

2013-04-15 03:10:37 ERROR [nova.openstack.common.rpc.amqp] Exception during message handling
Traceback (most recent call last):
  File "/opt/stack/nova/nova/openstack/common/rpc/amqp.py", line 430, in _process_data
    rval = self.proxy.dispatch(ctxt, version, method, **args)
  File "/opt/stack/nova/nova/openstack/common/rpc/dispatcher.py", line 133, in dispatch
    return getattr(proxyobj, method)(ctxt, **kwargs)
  File "/opt/stack/nova/nova/network/manager.py", line 1817, in create_networks
    self, context, vpn=True, **kwargs)
  File "/opt/stack/nova/nova/network/manager.py", line 1058, in create_networks
    return self._do_create_networks(context, **kwargs)
  File "/opt/stack/nova/nova/network/manager.py", line 1187, in _do_create_networks
    network = self.db.network_create_safe(context, net)
  File "/opt/stack/nova/nova/db/api.py", line 797, in network_create_safe
    return IMPL.network_create_safe(context, values)
  File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 96, in wrapper
    return f(*args, **kwargs)
  File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 2164, in network_create_safe
    raise exception.DuplicateVlan(vlan=values['vlan'])
DuplicateVlan: Detected existing vlan with id 100
2013-04-15 03:10:37 DEBUG [nova.openstack.common.rpc.amqp] Pool creating new connection
2013-04-15 03:10:37 INFO [nova.openstack.common.rpc.common] Connected to AMQP server on localhost:5672
2013-04-15 03:10:37 ERROR [nova.openstack.common.rpc.common] Returning exception Detected existing vlan with id 100 to caller
2013-04-15 03:10:37 ERROR [nova.openstack.common.rpc.common] ['Traceback (most recent call last):\n', ' File "/opt/stack/nova/nova/openstack/common/rpc/amqp.py", line 430, in _process_data\n rval = self.proxy.dispatch(ctxt, version, method, **args)\n', ' File "/opt/stack/nova/nova/openstack/common/rpc/dispatcher.py", line 133, in dispatch\n return getattr(proxyobj, method)(ctxt, **kwargs)\n', ' File "/opt/stack/nova/nova/network/manager.py", line 1817, in create_networks\n self, context, vpn=True, **kwargs)\n', ' File "/opt/stack/nova/nova/network/manager.py", line 1058, in create_networks\n return self._do_create_networks(context, **kwargs)\n', ' File "/opt/stack/nova/nova/network/manager.py", line 1187, in _do_create_networks\n network = self.db.network_create_safe(context, net)\n', ' File "/opt/stack/nova/nova/db/api.py", line 797, in network_create_safe\n return IMPL.network_create_safe(context, values)\n', ' File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 96, in wrapper\n return f(*args, **kwargs)\n', ' File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 2164, in network_create_safe\n raise exception.DuplicateVlan(vlan=values[\'vlan\'])\n', 'DuplicateVlan: Detected existing vlan with id 100\n']

This is because "vlan" is set to the default value 100, if the --vlan option isn't set.
So I think we should make "vlan" an essential option to fix to bug.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/34529
Committed: http://github.com/openstack/nova/commit/ec4a9490047106b36c8a6bdf91fc7579b84868dd
Submitter: Jenkins
Branch: master

commit ec4a9490047106b36c8a6bdf91fc7579b84868dd
Author: Alvaro Lopez Garcia <email address hidden>
Date: Wed Jul 17 13:20:33 2013 +0200

    Fix network creation in Vlan mode

    - If "vlan" is specified when creating a network, we honour the option.
    - If it is not specified, the Vlan number is calculated as follows:
    CONF.vlan_start + num_existing_networks + index_of_requested_network
    - If the above vlan is in use, try to get the next free vlan.

    Fixes bug 1194835
    Fixes bug 1169026

    Change-Id: Id4476c14f9dadcf498a499534337477b3f64f604

[Jian Wen (wenjianhn)]

If vlan is not specified, instead of calculating why not just use the smallest available vlan id?