Open Stack

On 05/02/2018 10:25 AM, Chris Dent wrote:
> On Wed, 2 May 2018, Thomas Goirand wrote:
> 
>> What was disturbing was that, doing the same request with curl worked
>> perfectly. Even more disturbing, it looked like I was having the issue
>> nearly always in virtualbox, but not always in real hardware, where it
>> sometimes worked.
> 
> What was making the request in the first place? It fails in X, but
> works in curl. What is X?

For example, nova-compute querying nova-placement-api.
Another example: openstackclient. It happened to me trying to configure
keystone when running puppet-openstack, for example, but on the command
line directly as well, simply trying to add users, projects, etc. This
looks like to me as a general problem in all of the OpenStack WSGI
applications.

>> Anyway, finally, I figured out that adding:
>>
>> --rem-header Content-Lenght
> 
> You added this arg to what?

As a parameter to uwsgi, so that it removes the Content-Lenght that the
WSGI application sends.

>> This however, looks like a workaround rather than a fix, and I wonder if
>> there's a real issue somewhere that needs to be fixed in a better way,
>> maybe in openstackclient or some other component...
> 
> Yeah, it sounds like something could be setting a bad value for the
> content length header and uwsgi is timing out while trying to read
> that much data (meaning, it is believing the content-length header)
> but there isn't anything actually there.
> 
> Another option is that there are buffer size problems in the uwsgi
> configuration but it's hard to speculate because it is not clear
> what requests and tools you're actually talking about here.

When attempting to google for the issue, I saw a lot of people that had
this problem fixed by adding --buffer-size 65535, as the default 4k
header of uwsgi was not enough. I also have this option set, as it seems
a reasonable thing to have, but that was not enough to fix the problem.
Only the --rem-header thing did.

If you want to try, you can simply use the stretch-queens.debian.net
repository with Glance (or simply Debian Sid), and edit
/etc/glance/glance-api-wsgi.ini to change the uwsgi parameters (I've
just switched Glance to uwsgi, since it now works...). I haven't checked
with Glance, but since I saw the problem with nova-placement-api,
cinder-api and keystone, I don't see why it wouldn't happen there.

Cheers,

Thomas Goirand (zigo)