When metadata is enabled, l3 agent db loop raises at each iteration

[Salvatore Orlando]

An incorrect statement is executed when setting up floating ips for a router:

            rules.append('PREROUTING', '-s 0.0.0.0/0 -d 169.254.169.254/32 '
                         '-p tcp -m tcp --dport 80 -j DNAT '
                         '--to-destination %s:%s' %
                         (self.conf.metadata_ip, self.conf.metadata_port))

The arguments for the rule should be passed as a tuple. Thanks Gary for spotting this.
As a result, the external gateway port is never updated in self.router_info, causing external_gateway_added to be invoked at each iteration. This will cause the error visible on the console, concerning the inability of adding again the default route:

Command: ['sudo', 'ip', 'netns', 'exec', 'qrouter-9eccafc4-0258-4fd1-91ec-c0dcbb7f2402', 'route', 'add', 'default', 'gw', '172.24.4.225']
Exit code: 7
Stdout: ''
Stderr: 'SIOCADDRT: File exists\n'
2012-09-03 13:58:58 ERROR [quantum.agent.l3_agent] Error running l3_nat daemon_loop
Traceback (most recent call last):
  File "/opt/stack/quantum/quantum/agent/l3_agent.py", line 167, in daemon_loop
    self.do_single_loop()
  File "/opt/stack/quantum/quantum/agent/l3_agent.py", line 212, in do_single_loop
    self.process_router(ri)
  File "/opt/stack/quantum/quantum/agent/l3_agent.py", line 264, in process_router
    self.external_gateway_added(ri, ex_gw_port, internal_cidrs)
  File "/opt/stack/quantum/quantum/agent/l3_agent.py", line 351, in external_gateway_added
    ip_wrapper.netns.execute(cmd)
  File "/opt/stack/quantum/quantum/agent/linux/ip_lib.py", line 332, in execute
    root_helper=self._parent.root_helper)
  File "/opt/stack/quantum/quantum/agent/linux/utils.py", line 55, in execute
    raise RuntimeError(m)
RuntimeError:
Command: ['sudo', 'ip', 'netns', 'exec', 'qrouter-9eccafc4-0258-4fd1-91ec-c0dcbb7f2402', 'route', 'add', 'default', 'gw', '172.24.4.225']
Exit code: 7
Stdout: ''
Stderr: 'SIOCADDRT: File exists\n'

Another side effect is that external_gateway_removed is never invoked.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/12316

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/12316
Committed: http://github.com/openstack/quantum/commit/6beb9e079b00b010c2ba756882c619d3c5159e24
Submitter: Jenkins
Branch: master

commit 6beb9e079b00b010c2ba756882c619d3c5159e24
Author: Salvatore Orlando <email address hidden>
Date: Mon Sep 3 05:43:29 2012 -0700

    Fix error in rule for metadata server dnat

    Fixes bug 1045312

    Change-Id: Ie0e2aa7e638a7cd50c87ae6d4fa807cb7733c3d1