Small correction to the above. Heartbeats will technically not stop
working as a result of the change of default but they will revert back
to using greenthreads in wsgi services which at the time of that config
option being added was considered to be suboptimal and hence this could
be considered a regression. Therefore I have opened a separate bug [1]
so that we can set to True for wsgi services. Note that the default has
already been changed for > Yoga (i.e. all versions above Jammy).

[1] https://bugs.launchpad.net/charm-nova-cloud-controller/+bug/2073260

** Description changed:

  When performing a heartbeat to rabbit (inside a nova-compute process),
  there is a greenlet error which causes a hard crash.
  
  I'm not exactly sure what details are relevant, but can provide more
  info if there's something that will be useful!
  
  This is on RHEL7 (essentially... somewhat custom image based on it)
  
  Log snippet:
  
  ```
  2021-07-07 19:34:52,686 DEBUG [oslo.messaging._drivers.impl_rabbit] 
/opt/openstack/venv/nova-23.0.20031033070/lib/python3.8/site-packages/oslo_messaging/_drivers/impl_rabbit.py:__init__:608
 [279fc413-9d7c-4fad-89e8-8de308658947] Connecting to AMQP server on 
127.0.0.1:5671
  2021-07-07 19:34:52,699 DEBUG [amqp.connection.Connection.heartbeat_tick] 
/opt/openstack/venv/nova-23.0.20031033070/lib/python3.8/site-packages/amqp/connection.py:heartbeat_tick:726
 heartbeat_tick : for connection 79f7cf4331b34cb0a2e3608281076773
  2021-07-07 19:34:52,699 DEBUG [amqp.connection.Connection.heartbeat_tick] 
/opt/openstack/venv/nova-23.0.20031033070/lib/python3.8/site-packages/amqp/connection.py:heartbeat_tick:740
 heartbeat_tick : Prev sent/recv: None/None, now - 6/6, monotonic - 
9634.717472491, last_heartbeat_sent - 9634.717470288, heartbeat int. - 60 for 
connection 79f7cf4331b34cb0a2e3608281076773
  2021-07-07 19:34:52,700 DEBUG [amqp.connection.Connection.heartbeat_tick] 
/opt/openstack/venv/nova-23.0.20031033070/lib/python3.8/site-packages/amqp/connection.py:heartbeat_tick:726
 heartbeat_tick : for connection 79f7cf4331b34cb0a2e3608281076773
  2021-07-07 19:34:52,701 DEBUG [amqp.connection.Connection.heartbeat_tick] 
/opt/openstack/venv/nova-23.0.20031033070/lib/python3.8/site-packages/amqp/connection.py:heartbeat_tick:740
 heartbeat_tick : Prev sent/recv: 6/6, now - 6/6, monotonic - 9634.719438155, 
last_heartbeat_sent - 9634.717470288, heartbeat int. - 60 for connection 
79f7cf4331b34cb0a2e3608281076773
  2021-07-07 19:34:52,718 DEBUG [amqp] 
/opt/openstack/venv/nova-23.0.20031033070/lib/python3.8/site-packages/amqp/connection.py:_on_start:382
 Start from server, version: 0.9, properties: {'capabilities': 
{'publisher_confirms': True, 'exchange_exchange_bindings': True, 'basic.nack': 
True, 'consumer_cancel_notify': True, 'connection.blocked': True, 
'consumer_priorities': True, 'authentication_failure_close': True, 
'per_consumer_qos': True, 'direct_reply_to': True}, 'cluster_name': 
'[email protected]', 'copyright': 'Copyright (c) 2007-2020 VMware, 
Inc. or its affiliates.', 'information': 'Licensed under the MPL 1.1. Website: 
https://rabbitmq.com', 'platform': 'Erlang/OTP 23.0.2', 'product': 'RabbitMQ', 
'version': '3.8.5'}, mechanisms: [b'PLAIN', b'AMQPLAIN', b'EXTERNAL'], locales: 
['en_US']
  2021-07-07 19:34:52,719 DEBUG [amqp] 
/opt/openstack/venv/nova-23.0.20031033070/lib/python3.8/site-packages/amqp/channel.py:__init__:104
 using channel_id: 1
  2021-07-07 19:34:52,720 DEBUG [amqp] 
/opt/openstack/venv/nova-23.0.20031033070/lib/python3.8/site-packages/amqp/channel.py:_on_open_ok:444
 Channel open
  2021-07-07 19:34:52,721 DEBUG [amqp.connection.Connection.heartbeat_tick] 
/opt/openstack/venv/nova-23.0.20031033070/lib/python3.8/site-packages/amqp/connection.py:heartbeat_tick:726
 heartbeat_tick : for connection c0299792d20e42a2b0a17d037d7d3058
  Traceback (most recent call last):
  File 
"/opt/openstack/venv/nova-23.0.20031033070/lib/python3.8/site-packages/eventlet/hubs/hub.py",
 line 476, in fire_timers
  timer()
  File 
"/opt/openstack/venv/nova-23.0.20031033070/lib/python3.8/site-packages/eventlet/hubs/timer.py",
 line 59, in __call__
  cb(*args, **kw)
  File 
"/opt/openstack/venv/nova-23.0.20031033070/lib/python3.8/site-packages/eventlet/semaphore.py",
 line 152, in _do_acquire
  waiter.switch()
  greenlet.error: cannot switch to a different thread
  ```
  
  Versions:
  
  ```
  oslo.messaging==12.7.1
  nova==23.0.2 (packaged locally from stable/wallaby as of July 3, 2021)
  ```
  
  
-------------------------------------------------------------------------------
  
  [Impact]
  The Nova default value of heartbeat_in_pthread needs to be False for non-wsgi 
services otherwise they crash when attempting to send a heartbeat message e.g. 
in a greenthread like nova-compute. This backports the patch to Jammy/Yoga in 
Ubuntu.
  
  [Test Plan]
  * Deploy Openstack Yoga on Jammy and ensure nova-compute has debug=True
  * ensure "oslo_messaging_rabbit.heartbeat_in_pthread = False" by checking 
latest entry in /var/log/nova/nova-compute.log
  * By default a heartbeat is checked 2 times every 60 seconds
  * Check /var/log/nova/nova-compute.log and ensure that do not see any 
"greenlet.error: cannot switch to a different thread" errors
  
  [Regression Potential]
- No regressions are expected as a result of this patch.
+ Changing the default to False will mean that while services not running under 
wsgi will be fixed, services that are running under wsgi will revert back to 
using their native threading method i.e. greenthreads which is considered 
suboptimal and in very loaded environments this could have a perceived impact
+ on api performance. A separate bug 
https://bugs.launchpad.net/charm-nova-cloud-controller/+bug/2073260 has been 
opened to address this.

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1934937

Title:
  Heartbeat in pthreads in nova-wallaby crashes with greenlet error

To manage notifications about this bug go to:
https://bugs.launchpad.net/cloud-archive/+bug/1934937/+subscriptions


-- 
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to