allow disable wsgi keepalive

[Edward Hope-Morley]

The wsgi server used in most if not all openstack services currently has keepalive=True by default thus keeping connections open after each request. This can cause problems when using load balancers in front of these services since connections for requests that take a long time can get closed/timeout in the load balancers. This can then cause issues for clients that persist their connections e.g. if a client performs a request using the same source port as a previous request that is not closed in the LB but still open in the server due to TCP packet sequencing in the LB and the new client not expecting the connection to already be open. So, it would be useful to be able to either disable wsgi keepalive or set the tcp_keealive timeout value on the wsgi socket like in cinder:

https://github.com/openstack/cinder/blob/master/cinder/wsgi.py#L169

[Dolph Mathews (dolph)]

Can you add the other affected services to this bug?

[Edward Hope-Morley (hopem)]

Dolph, having looked closer the other services (at least Nova, Glance, Cinder) already enable SO_KEEPALIVE and provide an optional tcp_keepidle so that should be sufficient for now. I will simply port that functionality to keystone for now and we can add/modify if necessary.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/62036

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/62036
Committed: https://git.openstack.org/cgit/openstack/keystone/commit/?id=e71f615d9f15595cec163e4fe78c0cd3796ad397
Submitter: Jenkins
Branch: master

commit e71f615d9f15595cec163e4fe78c0cd3796ad397
Author: Edward Hope-Morley <email address hidden>
Date: Fri Dec 13 15:30:49 2013 +0000

    Adds tcp_keepalive and tcp_keepidle config options

    Currently the wsgi server will not close connections once requests
    complete and will not enable keepalive on it's wsgi sockets. This can
    be a problem for those who need to align the server keepalive with
    load balancer timeouts without modifying system keepalive settings.

    To remedy this we add new config options tcp_keepalive and
    tcp_keepidle which are disabled by default to remain backwards
    compatible.

    DocImpact: "new config options for wsgi tcp_keepalive & tcp_keepidle"
    Closes-bug: bug 1260406
    Co-authored-by: Hirofumi Ichihara <email address hidden>
    Change-Id: Ic53402c57e1ebe44cde4c18e5e15200dcbbcb04b