Nova and its use of Olso Incubator Guru Meditation Reports

This blogs describes a error reporting / troubleshooting feature added to Nova a while back which people are probably not generally aware of.

One of the early things I worked on in the Nova libvirt driver was integration of support for the libvirt event notification system. This allowed Nova to get notified when instances are shutdown by the guest OS administrator, instead of having to wait for the background power state sync task to run. Supporting libvirt events was a theoretically simple concept, but in practice there was a nasty surprise. The key issue was that we needed to have a native thread running the libvirt event loop, while the rest of Nova uses green threads. The code kept getting bizarre deadlocks, which were eventually traced to use of the python logging APIs in the native thread. Since eventlet had monkeypatched the thread mutex primitives, the logging APIs couldn’t be safely called from the native thread as they’d try to obtain a green mutex from a native thread context.

Eventlet has a concept of a backdoor port, which lets you connect to the python process using telnet and get an interactive python prompt. After turning this on, I got a stack trace of all green and native threads and eventually figured out the problem, which was great. Sadly the eventlet backdoor is not something anyone sane would ever enable out of the box on production systems – you don’t really want to allow remote command execution to anyone who can connect to a TCP port :-) Another debugging option is to use Python’s native debugger, but this is again something you have to enable ahead of time and won’t be something admins enable out of the box on production systems. It is possible to connect to a running python process with GDB and get a crude stack trace, but that’s not great either as it requires python debuginfo libraries installed. It would be possible to build an administrative debugging API for Nova using the REST API, but that only works if the REST API & message bus are working – not something that’s going to be much use when Nova itself has deadlocked the entire python interpretor

After this debugging experience I decided to propose something that I’ve had on previous complex systems, a facility that allows an admin to trigger a live error report. Crucially this facility must not require any kind of deployment setup tasks and thus be guaranteed available at all times, especially on production systems where debugging options are limited by the need to maintain service to users. I called the proposal the “Guru Meditation Report” in reference to old Amiga crash reports. I did a quick proof of concept to test the idea, but Solly Ross turned the idea into a complete feature for OpenStack, adding it to the Oslo Incubator in the openstack.common.reports namespace and integrating with Nova. This shipped with the Icehouse release of Nova.

Service integration & usage

Integration into projects is quite straightforward, the openstack-common.conf file needs to list the relevant modules to import from oslo-incubator

$ grep report openstack-common.conf
module=report
module=report.generators
module=report.models
module=report.views
module=report.views.json
module=report.views.text
module=report.views.xml

then each service process needs to initialize the error report system. This just requires a single import line and method call from the main method

$ cat nova/cmd/nova-compute
...snip...
from nova.openstack.common.report import guru_meditation_report as gmr
...snip...
def main():
    gmr.TextGuruMeditation.setup_autorun(version)

    ...run eventlet service or whatever...

The setup_autorun method installs a signal handler connected to SIGUSR1 which will dump an error report to stderr when triggered.

So from Icehouse onwards, if any Nova process is mis-behaving you can simply run something like

$ kill -USR1 `pgrep nova-compute`

to get a detailed error report of the process state sent to stderr. On RHEL-7 / Fedora systems this data should end up going into the systemd journal for that service. On other systems you may be lucky enough for the init service to have redirected stderr to a log file, or unlucky enough to have it sent to /dev/null. Did I mention the systemd journal is a really exactly feature when troubleshooting service problems :-)

Error report information

In the oslo-incubator code there are 5 standard sections defined for the error report

• Config – dump of all configuration settings loaded by oslo.config – useful because the config settings loaded in memory don’t necessarily match what is currently stored in /etc/nova/nova.conf on disk – eg admin may have modified the config and forgotten to reload the services.
• Package – information about the software package, as passed into the setup_autorun method previously. This lets you know the openstack release version number, the vendor who packaged it and any vendor specific version info such as the RPM release number. This is again key, because what’s installed on the host currently may not match the version that’s actually running. You can’t always trust the admins to give you correct info when reporting bugs, so having software report itself is more reliable.
• Process – information about the running process including the process ID, parent process ID, user ID, group ID and scheduler state.
• Green Threads – stack trace of every eventlet green thread currently in existence
• Native Threads – stack trace of every native thread currently in existence

The report framework is modular, so it is possible to register new generator functions which add further data to the error report. This is useful if there is application specific data that is useful to include, that would not otherwise be suitable for inclusion in oslo-incubator directly. The data model is separated from the output formatting code, so it is possible to output the report in a number of different data formats. The reports which get sent to stderr are using a crude plain text format, but it is possible to have reports generated in XML, JSON, or another completely custom format.

Future improvements

Triggering from a UNIX signal and printing to stderr, is a very simple and reliable approach that we can guarantee will almost always work no matter what operational state the OpenStack deployment as a whole is in. It should not be considered the only possible approach though. I can see that it may be desirable to also wire this up to RPC messaging bus, so a cloud admin can remotely generate an error report for a service and get the response back over the message bus in an XML or JSON format. This wouldn’t replace the SIGUSR1 based stderr dumps, but rather augment them, as we want to retain the ability to trigger reports even if rabbitmq bus connection is dead/broken for some reason.

AFAIK, this error report system is only wired up into the Nova project at this time. It is desirable to bring this feature over to projects like Neutron, Cinder, Glance, Keystone too, so it can be a considered an openstack wide standard system for admins to collect data for troubleshooting. As explained above, this is no more difficult that adding the modules to openstack-common.conf and then adding a single method call to the service startup main method. Those projects might like to register extra error report sections to provide further data, but that’s by no means required for initial integration.

Having error reports triggered on demand by the admin is nice, but I think there is also value in having error reports triggered automatically in response to unexpected error conditions. For example if a RPC request to boot a new VM instance fails, it could be desirable to save a detailed error report, rather than just having an exception hit the logs with no context around it. In such a scenario you would extend the error report generator so that the report included the exception information & stack trace, and also include the headers and/or payload of the RPC request that failed. The error report would probably be written to a file instead of stderr, using JSON or XML. Tools could then be written to analyse error reports and identify commonly recurring problems.

Even with the current level of features for the error report system, it has proved its worth in facilitating the debugging of a number of problems in Nova, where things like the eventlet backdoor or python debugger were impractical to use. I look forward to its continued development and broader usage across openstack.

Example report

What follows below is an example error report from the nova-compute service running in one of my development hosts. Notice that oslo.conf configuration parameters that were declared with the ‘secret’ flag have their value masked. This is primarily aiming to prevent passwords making their way into the error report, since the expectation is the users may attach these reports to public bugs.

========================================================================
====                        Guru Meditation                         ====
========================================================================
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||


========================================================================
====                            Package                             ====
========================================================================
product = OpenStack Nova
vendor = OpenStack Foundation
version = 2015.1
========================================================================
====                            Threads                             ====
========================================================================
------                  Thread #140157298652928                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140157307045632                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140157734876928                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140158288500480                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140158416287488                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140158424680192                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/home/berrange/src/cloud/nova/nova/virt/libvirt/host.py:113 in _native_thread
    `libvirt.virEventRunDefaultImpl()`

/usr/lib64/python2.7/site-packages/libvirt.py:340 in virEventRunDefaultImpl
    `ret = libvirtmod.virEventRunDefaultImpl()`

------                  Thread #140157684520704                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140158296893184                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140158305285888                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140157709698816                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140158322071296                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140157726484224                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140158330464000                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140157332223744                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140157701306112                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140157692913408                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140157315438336                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140158537955136                   ------

/usr/lib/python2.7/site-packages/eventlet/hubs/hub.py:346 in run
    `self.wait(sleep_time)`

/usr/lib/python2.7/site-packages/eventlet/hubs/poll.py:85 in wait
    `presult = self.do_poll(seconds)`

/usr/lib/python2.7/site-packages/eventlet/hubs/epolls.py:62 in do_poll
    `return self.poll.poll(seconds)`

------                  Thread #140158313678592                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140157718091520                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140157323831040                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

------                  Thread #140158338856704                   ------

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/eventlet/tpool.py:72 in tworker
    `msg = _reqq.get()`

/usr/lib64/python2.7/Queue.py:168 in get
    `self.not_empty.wait()`

/usr/lib64/python2.7/threading.py:339 in wait
    `waiter.acquire()`

========================================================================
====                         Green Threads                          ====
========================================================================
------                        Green Thread                        ------

/usr/bin/nova-compute:9 in <module>
    `load_entry_point('nova==2015.1.dev352', 'console_scripts', 'nova-compute')()`

/home/berrange/src/cloud/nova/nova/cmd/compute.py:74 in main
    `service.wait()`

/home/berrange/src/cloud/nova/nova/service.py:444 in wait
    `_launcher.wait()`

/home/berrange/src/cloud/nova/nova/openstack/common/service.py:187 in wait
    `status, signo = self._wait_for_exit_or_signal(ready_callback)`

/home/berrange/src/cloud/nova/nova/openstack/common/service.py:170 in _wait_for_exit_or_signal
    `super(ServiceLauncher, self).wait()`

/home/berrange/src/cloud/nova/nova/openstack/common/service.py:133 in wait
    `self.services.wait()`

/home/berrange/src/cloud/nova/nova/openstack/common/service.py:473 in wait
    `self.tg.wait()`

/home/berrange/src/cloud/nova/nova/openstack/common/threadgroup.py:145 in wait
    `x.wait()`

/home/berrange/src/cloud/nova/nova/openstack/common/threadgroup.py:47 in wait
    `return self.thread.wait()`

/usr/lib/python2.7/site-packages/eventlet/greenthread.py:175 in wait
    `return self._exit_event.wait()`

/usr/lib/python2.7/site-packages/eventlet/event.py:121 in wait
    `return hubs.get_hub().switch()`

/usr/lib/python2.7/site-packages/eventlet/hubs/hub.py:294 in switch
    `return self.greenlet.switch()`

------                        Green Thread                        ------

No Traceback!

------                        Green Thread                        ------

/usr/lib/python2.7/site-packages/eventlet/green/thread.py:40 in __thread_body
    `func(*args, **kwargs)`

/usr/lib64/python2.7/threading.py:784 in __bootstrap
    `self.__bootstrap_inner()`

/usr/lib64/python2.7/threading.py:811 in __bootstrap_inner
    `self.run()`

/usr/lib64/python2.7/threading.py:764 in run
    `self.__target(*self.__args, **self.__kwargs)`

/usr/lib/python2.7/site-packages/qpid/selector.py:126 in run
    `rd, wr, ex = select(self.reading, self.writing, (), timeout)`

/usr/lib/python2.7/site-packages/eventlet/green/select.py:83 in select
    `return hub.switch()`

/usr/lib/python2.7/site-packages/eventlet/hubs/hub.py:294 in switch
    `return self.greenlet.switch()`

------                        Green Thread                        ------

/usr/lib/python2.7/site-packages/eventlet/greenthread.py:214 in main
    `result = function(*args, **kwargs)`

/home/berrange/src/cloud/nova/nova/openstack/common/service.py:492 in run_service
    `done.wait()`

/usr/lib/python2.7/site-packages/eventlet/event.py:121 in wait
    `return hubs.get_hub().switch()`

/usr/lib/python2.7/site-packages/eventlet/hubs/hub.py:294 in switch
    `return self.greenlet.switch()`

------                        Green Thread                        ------

/usr/lib/python2.7/site-packages/eventlet/greenthread.py:214 in main
    `result = function(*args, **kwargs)`

/home/berrange/src/cloud/nova/nova/virt/libvirt/host.py:124 in _dispatch_thread
    `self._dispatch_events()`

/home/berrange/src/cloud/nova/nova/virt/libvirt/host.py:228 in _dispatch_events
    `_c = self._event_notify_recv.read(1)`

/usr/lib64/python2.7/socket.py:380 in read
    `data = self._sock.recv(left)`

/usr/lib/python2.7/site-packages/eventlet/greenio.py:464 in recv
    `self._trampoline(self, read=True)`

/usr/lib/python2.7/site-packages/eventlet/greenio.py:439 in _trampoline
    `mark_as_closed=self._mark_as_closed)`

/usr/lib/python2.7/site-packages/eventlet/hubs/__init__.py:162 in trampoline
    `return hub.switch()`

/usr/lib/python2.7/site-packages/eventlet/hubs/hub.py:294 in switch
    `return self.greenlet.switch()`

------                        Green Thread                        ------

/usr/lib/python2.7/site-packages/eventlet/tpool.py:55 in tpool_trampoline
    `_c = _rsock.recv(1)`

/usr/lib/python2.7/site-packages/eventlet/greenio.py:325 in recv
    `timeout_exc=socket.timeout("timed out"))`

/usr/lib/python2.7/site-packages/eventlet/greenio.py:200 in _trampoline
    `mark_as_closed=self._mark_as_closed)`

/usr/lib/python2.7/site-packages/eventlet/hubs/__init__.py:162 in trampoline
    `return hub.switch()`

/usr/lib/python2.7/site-packages/eventlet/hubs/hub.py:294 in switch
    `return self.greenlet.switch()`

------                        Green Thread                        ------

/usr/lib/python2.7/site-packages/eventlet/greenthread.py:214 in main
    `result = function(*args, **kwargs)`

/usr/lib/python2.7/site-packages/oslo_utils/excutils.py:92 in inner_func
    `return infunc(*args, **kwargs)`

/usr/lib/python2.7/site-packages/oslo_messaging/_executors/impl_eventlet.py:93 in _executor_thread
    `incoming = self.listener.poll()`

/usr/lib/python2.7/site-packages/oslo_messaging/_drivers/amqpdriver.py:121 in poll
    `self.conn.consume(limit=1, timeout=timeout)`

/usr/lib/python2.7/site-packages/oslo_messaging/_drivers/impl_qpid.py:755 in consume
    `six.next(it)`

/usr/lib/python2.7/site-packages/oslo_messaging/_drivers/impl_qpid.py:685 in iterconsume
    `yield self.ensure(_error_callback, _consume)`

/usr/lib/python2.7/site-packages/oslo_messaging/_drivers/impl_qpid.py:602 in ensure
    `return method()`

/usr/lib/python2.7/site-packages/oslo_messaging/_drivers/impl_qpid.py:669 in _consume
    `timeout=poll_timeout)`

<string>:6 in next_receiver
    (source not found)

/usr/lib/python2.7/site-packages/qpid/messaging/endpoints.py:674 in next_receiver
    `if self._ecwait(lambda: self.incoming, timeout):`

/usr/lib/python2.7/site-packages/qpid/messaging/endpoints.py:50 in _ecwait
    `result = self._ewait(lambda: self.closed or predicate(), timeout)`

/usr/lib/python2.7/site-packages/qpid/messaging/endpoints.py:580 in _ewait
    `result = self.connection._ewait(lambda: self.error or predicate(), timeout)`

/usr/lib/python2.7/site-packages/qpid/messaging/endpoints.py:218 in _ewait
    `result = self._wait(lambda: self.error or predicate(), timeout)`

/usr/lib/python2.7/site-packages/qpid/messaging/endpoints.py:197 in _wait
    `return self._waiter.wait(predicate, timeout=timeout)`

/usr/lib/python2.7/site-packages/qpid/concurrency.py:59 in wait
    `self.condition.wait(timeout - passed)`

/usr/lib/python2.7/site-packages/qpid/concurrency.py:96 in wait
    `sw.wait(timeout)`

/usr/lib/python2.7/site-packages/qpid/compat.py:53 in wait
    `ready, _, _ = select([self], [], [], timeout)`

/usr/lib/python2.7/site-packages/eventlet/green/select.py:83 in select
    `return hub.switch()`

/usr/lib/python2.7/site-packages/eventlet/hubs/hub.py:294 in switch
    `return self.greenlet.switch()`

------                        Green Thread                        ------

/home/berrange/src/cloud/nova/nova/openstack/common/loopingcall.py:90 in _inner
    `greenthread.sleep(-delay if delay < 0 else 0)`

/usr/lib/python2.7/site-packages/eventlet/greenthread.py:34 in sleep
    `hub.switch()`

/usr/lib/python2.7/site-packages/eventlet/hubs/hub.py:294 in switch
    `return self.greenlet.switch()`

------                        Green Thread                        ------

/usr/lib/python2.7/site-packages/eventlet/greenthread.py:214 in main
    `result = function(*args, **kwargs)`

/home/berrange/src/cloud/nova/nova/openstack/common/loopingcall.py:133 in _inner
    `greenthread.sleep(idle)`

/usr/lib/python2.7/site-packages/eventlet/greenthread.py:34 in sleep
    `hub.switch()`

/usr/lib/python2.7/site-packages/eventlet/hubs/hub.py:294 in switch
    `return self.greenlet.switch()`

========================================================================
====                           Processes                            ====
========================================================================
Process 27760 (under 27711) [ run by: berrange (1000), state: running ]

========================================================================
====                         Configuration                          ====
========================================================================

cells: 
  bandwidth_update_interval = 600
  call_timeout = 60
  capabilities = 
    hypervisor=xenserver;kvm
    os=linux;windows
  cell_type = compute
  enable = False
  manager = nova.cells.manager.CellsManager
  mute_child_interval = 300
  name = nova
  reserve_percent = 10.0
  topic = cells

cinder: 
  cafile = None
  catalog_info = volumev2:cinderv2:publicURL
  certfile = None
  cross_az_attach = True
  endpoint_template = None
  http_retries = 3
  insecure = False
  keyfile = None
  os_region_name = None
  timeout = None

conductor: 
  manager = nova.conductor.manager.ConductorManager
  topic = conductor
  use_local = False
  workers = None

database: 
  backend = sqlalchemy
  connection = ***
  connection_debug = 0
  connection_trace = False
  db_inc_retry_interval = True
  db_max_retries = 20
  db_max_retry_interval = 10
  db_retry_interval = 1
  idle_timeout = 3600
  max_overflow = None
  max_pool_size = None
  max_retries = 10
  min_pool_size = 1
  mysql_sql_mode = TRADITIONAL
  pool_timeout = None
  retry_interval = 10
  slave_connection = ***
  sqlite_db = nova.sqlite
  sqlite_synchronous = True
  use_db_reconnect = False
  use_tpool = False

default: 
  allow_migrate_to_same_host = True
  allow_resize_to_same_host = True
  allow_same_net_traffic = True
  amqp_auto_delete = False
  amqp_durable_queues = False
  api_paste_config = /etc/nova/api-paste.ini
  api_rate_limit = False
  auth_strategy = keystone
  auto_assign_floating_ip = False
  backdoor_port = None
  bandwidth_poll_interval = 600
  bindir = /usr/bin
  block_device_allocate_retries = 60
  block_device_allocate_retries_interval = 3
  boot_script_template = /home/berrange/src/cloud/nova/nova/cloudpipe/bootscript.template
  ca_file = cacert.pem
  ca_path = /home/berrange/src/cloud/data/nova/CA
  cert_manager = nova.cert.manager.CertManager
  client_socket_timeout = 900
  cnt_vpn_clients = 0
  compute_available_monitors = 
    nova.compute.monitors.all_monitors
  compute_driver = libvirt.LibvirtDriver
  compute_manager = nova.compute.manager.ComputeManager
  compute_monitors = 
  compute_resources = 
    vcpu
  compute_stats_class = nova.compute.stats.Stats
  compute_topic = compute
  config-dir = None
  config-file = 
    /etc/nova/nova.conf
  config_drive_format = iso9660
  config_drive_skip_versions = 1.0 2007-01-19 2007-03-01 2007-08-29 2007-10-10 2007-12-15 2008-02-01 2008-09-01
  console_host = mustard.gsslab.fab.redhat.com
  console_manager = nova.console.manager.ConsoleProxyManager
  console_topic = console
  consoleauth_manager = nova.consoleauth.manager.ConsoleAuthManager
  consoleauth_topic = consoleauth
  control_exchange = nova
  create_unique_mac_address_attempts = 5
  crl_file = crl.pem
  db_driver = nova.db
  debug = True
  default_access_ip_network_name = None
  default_availability_zone = nova
  default_ephemeral_format = ext4
  default_flavor = m1.small
  default_floating_pool = public
  default_log_levels = 
    amqp=WARN
    amqplib=WARN
    boto=WARN
    glanceclient=WARN
    iso8601=WARN
    keystonemiddleware=WARN
    oslo.messaging=INFO
    qpid=WARN
    requests.packages.urllib3.connectionpool=WARN
    routes.middleware=WARN
    sqlalchemy=WARN
    stevedore=WARN
    suds=INFO
    urllib3.connectionpool=WARN
    websocket=WARN
  default_notification_level = INFO
  default_publisher_id = None
  default_schedule_zone = None
  defer_iptables_apply = False
  dhcp_domain = novalocal
  dhcp_lease_time = 86400
  dhcpbridge = /usr/bin/nova-dhcpbridge
  dhcpbridge_flagfile = 
    /etc/nova/nova.conf
  dmz_cidr = 
  dmz_mask = 255.255.255.0
  dmz_net = 10.0.0.0
  dns_server = 
  dns_update_periodic_interval = -1
  dnsmasq_config_file = 
  ebtables_exec_attempts = 3
  ebtables_retry_interval = 1.0
  ec2_listen = 0.0.0.0
  ec2_listen_port = 8773
  ec2_private_dns_show_ip = False
  ec2_strict_validation = True
  ec2_timestamp_expiry = 300
  ec2_workers = 2
  enable_new_services = True
  enabled_apis = 
    ec2
    metadata
    osapi_compute
  enabled_ssl_apis = 
  fake_call = False
  fake_network = False
  fatal_deprecations = False
  fatal_exception_format_errors = False
  firewall_driver = nova.virt.libvirt.firewall.IptablesFirewallDriver
  fixed_ip_disassociate_timeout = 600
  fixed_range_v6 = fd00::/48
  flat_injected = False
  flat_interface = p1p1
  flat_network_bridge = br100
  flat_network_dns = 8.8.4.4
  floating_ip_dns_manager = nova.network.noop_dns_driver.NoopDNSDriver
  force_config_drive = always
  force_dhcp_release = True
  force_raw_images = True
  force_snat_range = 
  forward_bridge_interface = 
    all
  gateway = None
  gateway_v6 = None
  heal_instance_info_cache_interval = 60
  host = mustard.gsslab.fab.redhat.com
  image_cache_manager_interval = 2400
  image_cache_subdirectory_name = _base
  injected_network_template = /home/berrange/src/cloud/nova/nova/virt/interfaces.template
  instance_build_timeout = 0
  instance_delete_interval = 300
  instance_dns_domain = 
  instance_dns_manager = nova.network.noop_dns_driver.NoopDNSDriver
  instance_format = [instance: %(uuid)s] 
  instance_name_template = instance-%08x
  instance_usage_audit = False
  instance_usage_audit_period = month
  instance_uuid_format = [instance: %(uuid)s] 
  instances_path = /home/berrange/src/cloud/data/nova/instances
  internal_service_availability_zone = internal
  iptables_bottom_regex = 
  iptables_drop_action = DROP
  iptables_top_regex = 
  ipv6_backend = rfc2462
  key_file = private/cakey.pem
  keys_path = /home/berrange/src/cloud/data/nova/keys
  keystone_ec2_insecure = False
  keystone_ec2_url = http://10.33.8.112:5000/v2.0/ec2tokens
  l3_lib = nova.network.l3.LinuxNetL3
  linuxnet_interface_driver = nova.network.linux_net.LinuxBridgeInterfaceDriver
  linuxnet_ovs_integration_bridge = br-int
  live_migration_retry_count = 30
  lockout_attempts = 5
  lockout_minutes = 15
  lockout_window = 15
  log-config-append = None
  log-date-format = %Y-%m-%d %H:%M:%S
  log-dir = None
  log-file = None
  log-format = None
  logging_context_format_string = %(asctime)s.%(msecs)03d %(color)s%(levelname)s %(name)s [%(request_id)s %(user_name)s %(project_name)s%(color)s] %(instance)s%(color)s%(message)s
  logging_debug_format_suffix = from (pid=%(process)d) %(funcName)s %(pathname)s:%(lineno)d
  logging_default_format_string = %(asctime)s.%(msecs)03d %(color)s%(levelname)s %(name)s [-%(color)s] %(instance)s%(color)s%(message)s
  logging_exception_prefix = %(color)s%(asctime)s.%(msecs)03d TRACE %(name)s %(instance)s
  max_age = 0
  max_concurrent_builds = 10
  max_header_line = 16384
  max_local_block_devices = 3
  maximum_instance_delete_attempts = 5
  memcached_servers = None
  metadata_host = 10.33.8.112
  metadata_listen = 0.0.0.0
  metadata_listen_port = 8775
  metadata_manager = nova.api.manager.MetadataManager
  metadata_port = 8775
  metadata_workers = 2
  migrate_max_retries = -1
  mkisofs_cmd = genisoimage
  monkey_patch = False
  monkey_patch_modules = 
    nova.api.ec2.cloud:nova.notifications.notify_decorator
    nova.compute.api:nova.notifications.notify_decorator
  multi_host = True
  multi_instance_display_name_template = %(name)s-%(count)d
  my_block_storage_ip = 10.33.8.112
  my_ip = 10.33.8.112
  network_allocate_retries = 0
  network_api_class = nova.network.api.API
  network_device_mtu = None
  network_driver = nova.network.linux_net
  network_manager = nova.network.manager.FlatDHCPManager
  network_size = 256
  network_topic = network
  networks_path = /home/berrange/src/cloud/data/nova/networks
  non_inheritable_image_properties = 
    bittorrent
    cache_in_nova
  notification_driver = 
  notification_topics = 
    notifications
  notify_api_faults = False
  notify_on_state_change = None
  novncproxy_base_url = http://10.33.8.112:6080/vnc_auto.html
  null_kernel = nokernel
  num_networks = 1
  osapi_compute_listen = 0.0.0.0
  osapi_compute_listen_port = 8774
  osapi_compute_workers = 2
  ovs_vsctl_timeout = 120
  password_length = 12
  pci_alias = 
  pci_passthrough_whitelist = 
  periodic_enable = True
  periodic_fuzzy_delay = 60
  policy_default_rule = default
  policy_dirs = 
    policy.d
  policy_file = policy.json
  preallocate_images = none
  project_cert_subject = /C=US/ST=California/O=OpenStack/OU=NovaDev/CN=project-ca-%.16s-%s
  public_interface = br100
  publish_errors = False
  pybasedir = /home/berrange/src/cloud/nova
  qpid_heartbeat = 60
  qpid_hostname = 10.33.8.112
  qpid_hosts = 
    10.33.8.112:5672
  qpid_password = ***
  qpid_port = 5672
  qpid_protocol = tcp
  qpid_receiver_capacity = 1
  qpid_sasl_mechanisms = 
  qpid_tcp_nodelay = True
  qpid_topology_version = 1
  qpid_username = 
  quota_cores = 20
  quota_driver = nova.quota.DbQuotaDriver
  quota_fixed_ips = -1
  quota_floating_ips = 10
  quota_injected_file_content_bytes = 10240
  quota_injected_file_path_length = 255
  quota_injected_files = 5
  quota_instances = 10
  quota_key_pairs = 100
  quota_metadata_items = 128
  quota_ram = 51200
  quota_security_group_rules = 20
  quota_security_groups = 10
  quota_server_group_members = 10
  quota_server_groups = 10
  reboot_timeout = 0
  reclaim_instance_interval = 0
  remove_unused_base_images = True
  remove_unused_original_minimum_age_seconds = 86400
  report_interval = 10
  rescue_timeout = 0
  reservation_expire = 86400
  reserved_host_disk_mb = 0
  reserved_host_memory_mb = 512
  resize_confirm_window = 0
  resize_fs_using_block_device = False
  resume_guests_state_on_host_boot = False
  rootwrap_config = /etc/nova/rootwrap.conf
  routing_source_ip = 10.33.8.112
  rpc_backend = qpid
  rpc_conn_pool_size = 30
  rpc_response_timeout = 60
  rpc_thread_pool_size = 64
  run_external_periodic_tasks = True
  running_deleted_instance_action = reap
  running_deleted_instance_poll_interval = 1800
  running_deleted_instance_timeout = 0
  scheduler_available_filters = 
    nova.scheduler.filters.all_filters
  scheduler_default_filters = 
    AvailabilityZoneFilter
    ComputeCapabilitiesFilter
    ComputeFilter
    ImagePropertiesFilter
    RamFilter
    RetryFilter
    ServerGroupAffinityFilter
    ServerGroupAntiAffinityFilter
  scheduler_manager = nova.scheduler.manager.SchedulerManager
  scheduler_max_attempts = 3
  scheduler_topic = scheduler
  scheduler_weight_classes = 
    nova.scheduler.weights.all_weighers
  security_group_api = nova
  send_arp_for_ha = True
  send_arp_for_ha_count = 3
  service_down_time = 60
  servicegroup_driver = db
  share_dhcp_address = False
  shelved_offload_time = 0
  shelved_poll_interval = 3600
  shutdown_timeout = 60
  snapshot_name_template = snapshot-%s
  ssl_ca_file = None
  ssl_cert_file = None
  ssl_key_file = None
  state_path = /home/berrange/src/cloud/data/nova
  sync_power_state_interval = 600
  syslog-log-facility = LOG_USER
  tcp_keepidle = 600
  teardown_unused_network_gateway = False
  tempdir = None
  transport_url = None
  until_refresh = 0
  update_dns_entries = False
  use-syslog = False
  use-syslog-rfc-format = False
  use_cow_images = True
  use_forwarded_for = False
  use_ipv6 = False
  use_network_dns_servers = False
  use_project_ca = False
  use_single_default_gateway = False
  use_stderr = True
  user_cert_subject = /C=US/ST=California/O=OpenStack/OU=NovaDev/CN=%.16s-%.16s-%s
  vcpu_pin_set = None
  vendordata_driver = nova.api.metadata.vendordata_json.JsonFileVendorData
  verbose = True
  vif_plugging_is_fatal = True
  vif_plugging_timeout = 300
  virt_mkfs = 
  vlan_interface = 
  vlan_start = 100
  vnc_enabled = True
  vnc_keymap = en-us
  vncserver_listen = 127.0.0.1
  vncserver_proxyclient_address = 127.0.0.1
  volume_api_class = nova.volume.cinder.API
  volume_usage_poll_interval = 0
  vpn_flavor = m1.tiny
  vpn_image_id = 0
  vpn_ip = 10.33.8.112
  vpn_key_suffix = -vpn
  vpn_start = 1000
  wsgi_default_pool_size = 1000
  wsgi_keep_alive = True
  wsgi_log_format = %(client_ip)s "%(request_line)s" status: %(status_code)s len: %(body_length)s time: %(wall_seconds).7f
  xvpvncproxy_base_url = http://10.33.8.112:6081/console

ephemeral_storage_encryption: 
  cipher = aes-xts-plain64
  enabled = False
  key_size = 512

glance: 
  allowed_direct_url_schemes = 
  api_insecure = False
  api_servers = 
    http://10.33.8.112:9292
  host = 10.33.8.112
  num_retries = 0
  port = 9292
  protocol = http

guestfs: 
  debug = False

keymgr: 
  api_class = nova.keymgr.conf_key_mgr.ConfKeyManager

libvirt: 
  block_migration_flag = VIR_MIGRATE_UNDEFINE_SOURCE, VIR_MIGRATE_PEER2PEER, VIR_MIGRATE_LIVE, VIR_MIGRATE_TUNNELLED, VIR_MIGRATE_NON_SHARED_INC
  checksum_base_images = False
  checksum_interval_seconds = 3600
  connection_uri = 
  cpu_mode = none
  cpu_model = None
  disk_cachemodes = 
  disk_prefix = None
  gid_maps = 
  glusterfs_mount_point_base = /home/berrange/src/cloud/data/nova/mnt
  hw_disk_discard = None
  hw_machine_type = None
  image_info_filename_pattern = /home/berrange/src/cloud/data/nova/instances/_base/%(image)s.info
  images_rbd_ceph_conf = 
  images_rbd_pool = rbd
  images_type = default
  images_volume_group = None
  inject_key = False
  inject_partition = -2
  inject_password = False
  iscsi_iface = None
  iscsi_use_multipath = False
  iser_use_multipath = False
  live_migration_bandwidth = 0
  live_migration_flag = VIR_MIGRATE_UNDEFINE_SOURCE, VIR_MIGRATE_PEER2PEER, VIR_MIGRATE_LIVE, VIR_MIGRATE_TUNNELLED
  live_migration_uri = qemu+ssh://berrange@%s/system
  mem_stats_period_seconds = 10
  nfs_mount_options = None
  nfs_mount_point_base = /home/berrange/src/cloud/data/nova/mnt
  num_aoe_discover_tries = 3
  num_iscsi_scan_tries = 5
  num_iser_scan_tries = 5
  qemu_allowed_storage_drivers = 
  quobyte_client_cfg = None
  quobyte_mount_point_base = /home/berrange/src/cloud/data/nova/mnt
  rbd_secret_uuid = None
  rbd_user = None
  remove_unused_kernels = False
  remove_unused_resized_minimum_age_seconds = 3600
  rescue_image_id = None
  rescue_kernel_id = None
  rescue_ramdisk_id = None
  rng_dev_path = None
  scality_sofs_config = None
  scality_sofs_mount_point = /home/berrange/src/cloud/data/nova/scality
  smbfs_mount_options = 
  smbfs_mount_point_base = /home/berrange/src/cloud/data/nova/mnt
  snapshot_compression = False
  snapshot_image_format = None
  snapshots_directory = /home/berrange/src/cloud/data/nova/instances/snapshots
  sparse_logical_volumes = False
  sysinfo_serial = auto
  uid_maps = 
  use_usb_tablet = False
  use_virtio_for_bridges = True
  virt_type = kvm
  volume_clear = zero
  volume_clear_size = 0
  volume_drivers = 
    aoe=nova.virt.libvirt.volume.LibvirtAOEVolumeDriver
    fake=nova.virt.libvirt.volume.LibvirtFakeVolumeDriver
    fibre_channel=nova.virt.libvirt.volume.LibvirtFibreChannelVolumeDriver
    glusterfs=nova.virt.libvirt.volume.LibvirtGlusterfsVolumeDriver
    gpfs=nova.virt.libvirt.volume.LibvirtGPFSVolumeDriver
    iscsi=nova.virt.libvirt.volume.LibvirtISCSIVolumeDriver
    iser=nova.virt.libvirt.volume.LibvirtISERVolumeDriver
    local=nova.virt.libvirt.volume.LibvirtVolumeDriver
    nfs=nova.virt.libvirt.volume.LibvirtNFSVolumeDriver
    quobyte=nova.virt.libvirt.volume.LibvirtQuobyteVolumeDriver
    rbd=nova.virt.libvirt.volume.LibvirtNetVolumeDriver
    scality=nova.virt.libvirt.volume.LibvirtScalityVolumeDriver
    sheepdog=nova.virt.libvirt.volume.LibvirtNetVolumeDriver
    smbfs=nova.virt.libvirt.volume.LibvirtSMBFSVolumeDriver
  wait_soft_reboot_seconds = 120
  xen_hvmloader_path = /usr/lib/xen/boot/hvmloader

osapi_v3: 
  enabled = True
  extensions_blacklist = 
  extensions_whitelist = 

oslo_concurrency: 
  disable_process_locking = False
  lock_path = /home/berrange/src/cloud/data/nova

rdp: 
  enabled = False
  html5_proxy_base_url = http://127.0.0.1:6083/

remote_debug: 
  host = None
  port = None

serial_console: 
  base_url = ws://127.0.0.1:6083/
  enabled = False
  listen = 127.0.0.1
  port_range = 10000:20000
  proxyclient_address = 127.0.0.1

spice: 
  agent_enabled = True
  enabled = False
  html5proxy_base_url = http://10.33.8.112:6082/spice_auto.html
  keymap = en-us
  server_listen = 127.0.0.1
  server_proxyclient_address = 127.0.0.1

ssl: 
  ca_file = None
  cert_file = None
  key_file = None

upgrade_levels: 
  baseapi = None
  cells = None
  compute = None
  conductor = None
  console = None
  consoleauth = None
  network = None
  scheduler = None

workarounds: 
  disable_libvirt_livesnapshot = True
  disable_rootwrap = False