LBaaS Haproxy occurs error if no member is added

[Bo Lin]

if VIP (only with session_persistence=HTTP_COOKIE)&Pool without one member added, the Haproxy agent would report config file error like the following:

2014-04-02 10:14:10.632 17283 DEBUG neutron.openstack.common.lockutils [req-18b873c4-abd7-4483-824f-f553c29ae549 None] Semaphore / lock released "deploy_instance" inner /opt/stack/neutron/neutron/openstack/common/lockutils.py:252
2014-04-02 10:14:10.633 17283 ERROR neutron.services.loadbalancer.agent.agent_manager [req-18b873c4-abd7-4483-824f-f553c29ae549 None] Unable to deploy instance for pool: a61dd6b6-8dbe-4576-b213-f8632892a58c
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager Traceback (most recent call last):
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager File "/opt/stack/neutron/neutron/services/loadbalancer/agent/agent_manager.py", line 180, in _reload_pool
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager self.device_drivers[driver_name].deploy_instance(logical_config)
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager File "/opt/stack/neutron/neutron/openstack/common/lockutils.py", line 249, in inner
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager return f(*args, **kwargs)
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager File "/opt/stack/neutron/neutron/services/loadbalancer/drivers/haproxy/namespace_driver.py", line 280, in deploy_instance
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager self.update(logical_config)
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager File "/opt/stack/neutron/neutron/services/loadbalancer/drivers/haproxy/namespace_driver.py", line 95, in update
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager self._spawn(logical_config, extra_args)
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager File "/opt/stack/neutron/neutron/services/loadbalancer/drivers/haproxy/namespace_driver.py", line 110, in _spawn
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager ns.netns.execute(cmd)
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager File "/opt/stack/neutron/neutron/agent/linux/ip_lib.py", line 466, in execute
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager check_exit_code=check_exit_code)
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager File "/opt/stack/neutron/neutron/agent/linux/utils.py", line 76, in execute
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager raise RuntimeError(m)
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager RuntimeError:
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager Command: ['sudo', '/usr/local/bin/neutron-rootwrap', '/etc/neutron/rootwrap.conf', 'ip', 'netns', 'exec', 'qlbaas-a61dd6b6-8dbe-4576-b213-f8632892a58c', 'haproxy', '-f', '/opt/stack/data/neutron/lbaas/a61dd6b6-8dbe-4576-b213-f8632892a58c/conf', '-p', '/opt/stack/data/neutron/lbaas/a61dd6b6-8dbe-4576-b213-f8632892a58c/pid', '-sf', '4524']
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager Exit code: 1
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager Stdout: ''
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager Stderr: '[ALERT] 091/101410 (20752) : config : HTTP proxy a61dd6b6-8dbe-4576-b213-f8632892a58c has a cookie but no server list !\n[ALERT] 091/101410 (20752) : Fatal errors found in configuration.\n'
2014-04-02 10:14:10.633 17283 TRACE neutron.services.loadbalancer.agent.agent_manager

I think one solution: check the member list, if no member exists, Haproxy agent would not deploy the instance or undeploy existed haproxy process.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/85251

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/86750

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/86750
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=0f2de5a3353c6951a88542f35be80b9ba9a55c0f
Submitter: Jenkins
Branch: master

commit 0f2de5a3353c6951a88542f35be80b9ba9a55c0f
Author: berlin <email address hidden>
Date: Fri Apr 11 08:04:47 2014 +0800

    Fix LBaaS Haproxy occurs error if no member is added

    If no member is added and session_persistence.type=HTTP_COOKIE,
    haproxy agent would not add cookie persistence option to the backend.
    Closes-Bug: #1302283

    Change-Id: Ifa2564df924c2555225a749a99c705b3f1caab4a