Open Stack

Hi,

I found that my controller nodes were a bit overloaded with 16 uwsgi
nova-api-os compute processes. I reduced the nova-api-os uwsgi processes
to 10 and timeout and slowdowns were eliminated. My cloud went stable
and the response times went lower. I have 20 vcpus on a Xeon(R) CPU
E5-2630 v4 @ 2.20GHz.

For the openstack-ansible I need to change this variable from 16 to 10:
nova_wsgi_processes_max: 10. Seems I need to set it to an equal number
of my cpu cores.

Regards,
Robert Varjasi
consultant at Component Soft Ltd.
Tel: +36/30-259-9221

On 10/08/2018 06:33 PM, Robert Varjasi wrote:
> Hi,
>
> After a few tempest run I noticed slowdowns in the nova-api-os-compute
> uwsgi  processes. I check the processes with py-spy and found that a lot
> of process blocked on read(). Here is my py-spy output from one of my
> nova-api-os-compute uwsgi process: http://paste.openstack.org/show/731677/
>
> And the stack trace:
>
> thread_id = Thread-2 filename = /usr/lib/python2.7/threading.py lineno =
> 774 function = __bootstrap line = self.__bootstrap_inner()
> thread_id = Thread-2 filename = /usr/lib/python2.7/threading.py lineno =
> 801 function = __bootstrap_inner line = self.run()
> thread_id = Thread-2 filename = /usr/lib/python2.7/threading.py lineno =
> 754 function = run line = self.__target(*self.__args, **self.__kwargs)
> thread_id = Thread-2 filename =
> /openstack/venvs/nova-17.0.4/lib/python2.7/site-packages/oslo_messaging/_drivers/amqpdriver.py
> lineno = 382 function = poll line =
> self.conn.consume(timeout=current_timeout)
> thread_id = Thread-2 filename =
> /openstack/venvs/nova-17.0.4/lib/python2.7/site-packages/oslo_messaging/_drivers/impl_rabbit.py
> lineno = 1083 function = consume line = error_callback=_error_callback)
> thread_id = Thread-2 filename =
> /openstack/venvs/nova-17.0.4/lib/python2.7/site-packages/oslo_messaging/_drivers/impl_rabbit.py
> lineno = 807 function = ensure line = ret, channel = autoretry_method()
> thread_id = Thread-2 filename =
> /openstack/venvs/nova-17.0.4/lib/python2.7/site-packages/kombu/connection.py
> lineno = 494 function = _ensured line = return fun(*args, **kwargs)
> thread_id = Thread-2 filename =
> /openstack/venvs/nova-17.0.4/lib/python2.7/site-packages/kombu/connection.py
> lineno = 570 function = __call__ line = return fun(*args,
> channel=channels[0], **kwargs), channels[0]
> thread_id = Thread-2 filename =
> /openstack/venvs/nova-17.0.4/lib/python2.7/site-packages/oslo_messaging/_drivers/impl_rabbit.py
> lineno = 796 function = execute_method line = method()
> thread_id = Thread-2 filename =
> /openstack/venvs/nova-17.0.4/lib/python2.7/site-packages/oslo_messaging/_drivers/impl_rabbit.py
> lineno = 1068 function = _consume line =
> self.connection.drain_events(timeout=poll_timeout)
> thread_id = Thread-2 filename =
> /openstack/venvs/nova-17.0.4/lib/python2.7/site-packages/kombu/connection.py
> lineno = 301 function = drain_events line = return
> self.transport.drain_events(self.connection, **kwargs)
> thread_id = Thread-2 filename =
> /openstack/venvs/nova-17.0.4/lib/python2.7/site-packages/kombu/transport/pyamqp.py
> lineno = 103 function = drain_events line = return
> connection.drain_events(**kwargs)
> thread_id = Thread-2 filename =
> /openstack/venvs/nova-17.0.4/lib/python2.7/site-packages/amqp/connection.py
> lineno = 471 function = drain_events line = while not
> self.blocking_read(timeout):
> thread_id = Thread-2 filename =
> /openstack/venvs/nova-17.0.4/lib/python2.7/site-packages/amqp/connection.py
> lineno = 476 function = blocking_read line = frame =
> self.transport.read_frame()
> thread_id = Thread-2 filename =
> /openstack/venvs/nova-17.0.4/lib/python2.7/site-packages/amqp/transport.py
> lineno = 226 function = read_frame line = frame_header = read(7, True)
> thread_id = Thread-2 filename =
> /openstack/venvs/nova-17.0.4/lib/python2.7/site-packages/amqp/transport.py
> lineno = 346 function = _read line = s = recv(n - len(rbuf))  # see note
> above
> thread_id = Thread-2 filename = /usr/lib/python2.7/ssl.py lineno = 643
> function = read line = v = self._sslobj.read(len)
>
> I am using nova 17.0.4.dev1, amqp (2.2.2), oslo.messaging (5.35.0),
> kombu (4.1.0). I have 3 controller nodes. The openstack deployed by OSA
> 17.0.4.
>
> I can reproduce the read() block if I click on "Log" in Horizon to see
> the console outputs from one of my VM or run a tempest test:
> tempest.api.compute.admin.test_hypervisor.HypervisorAdminTestJSON.test_get_hypervisor_uptime.
>
> The nova-api response time increasing when more and more nova-api
> processes get blocked at this read. Is it a normal behavior?
>
> --- 
> Regards,
> Robert Varjasi
> consultant at Component Soft Ltd.
>