Unable to tune KeepAlive in wsgi template

[Andrey Pavlov]

Sometimes during testing setup we can catch strange exception in client code

  File "/usr/local/lib/python3.6/site-packages/novaclient/base.py", line 192, in get
    new = self.manager.get(self.id)
  File "/usr/local/lib/python3.6/site-packages/novaclient/v2/servers.py", line 855, in get
    return self._get("/servers/%s" % base.getid(server), "server")
  File "/usr/local/lib/python3.6/site-packages/novaclient/base.py", line 353, in _get
    resp, body = self.api.client.get(url)
  File "/usr/local/lib/python3.6/site-packages/keystoneauth1/adapter.py", line 386, in get
    return self.request(url, 'GET', **kwargs)
  File "/usr/local/lib/python3.6/site-packages/novaclient/client.py", line 72, in request
    **kwargs)
  File "/usr/local/lib/python3.6/site-packages/keystoneauth1/adapter.py", line 545, in request
    resp = super(LegacyJsonAdapter, self).request(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/keystoneauth1/adapter.py", line 248, in request
    return self.session.request(url, method, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/keystoneauth1/session.py", line 913, in request
    resp = send(**kwargs)
  File "/usr/local/lib/python3.6/site-packages/keystoneauth1/session.py", line 1020, in _send_request
    raise exceptions.ConnectFailure(msg)
keystoneauth1.exceptions.connection.ConnectFailure: Unable to establish connection to http://252.1.200.72:8774/v2.1/servers/1c2fd218-52af-4615-b2ae-0e230e6024fb: ('Connection aborted.', RemoteDisconnected('Remote end closed connection without response',))

After some investigation we found that root cause is in KeepAlive options in wsgi template.
Here is the similar test case https://github.com/mikem23/keepalive-race

So we want to set "KeepAlive Off" in charm-nova-cloud-controller/templates/wsgi-api-os-compute.conf for this particular environment. (https://github.com/openstack/charm-nova-cloud-controller/blob/master/charmhelpers/contrib/openstack/templates/wsgi-openstack-api.conf)

[Chris MacNaughton (chris.macnaughton)]

Marking this as Triaged as it's a new feature request and doesn't need to sit in New forever.

[Nobuto Murata (nobuto)]

I've bumped the KeepAlive timeout to mitigate this known race condition:
https://bugs.launchpad.net/charm-helpers/+bug/1947010
It's going to be applied in the next release. It doesn't allow the customization of the value or on/off though.