Default neutron-ns-metadata-proxy threads setting is too low (newton)

[Michael Johnson]

In the older neutron-ns-metadata-proxy, in the newton release, the number of threads is fixed at 100. This is a drop from the previous default setting of 1000 as a side effect of changing the number of wsgi threads [1].

This is causing failures at sites with a large number of instances using deployment tools (instance cloud-init logs):
2017-08-01 15:44:36,773 - url_helper.py[WARNING]: Calling 'http://169.254.169.254/2009-04-04/meta-data/instance-id' failed [119/120s]: request error [HTTPConnectionPool(host='169.254.169.254', port=80): Request timed out. (timeout=17.0)]
2017-08-01 15:44:37,775 - DataSourceEc2.py[CRITICAL]: Giving up on md from ['http://169.254.169.254/2009-04-04/meta-data/instance-id'] after 120 seconds

Setting the value, for neutron-ns-metadata-proxy only, back up to 1000 resolves this issue.
It should also be noted that in the Ocata forward version of the neutron-ns-metadata-proxy the default value is 1024 [2].

I am going to propose a patch for stable/newton that sets the default thread count for the neutron-ns-metadata-proxy back up to 1000.

[1] https://github.com/openstack/neutron/blob/master/releasenotes/notes/config-wsgi-pool-size-a4c06753b79fee6d.yaml
[2] https://github.com/openstack/neutron/blob/master/neutron/agent/metadata/driver.py#L44

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/newton
Review: https://review.openstack.org/494313

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/494313
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=69752ca678be674dcbcde6c5e4874c44843a28d8
Submitter: Jenkins
Branch: stable/newton

commit 69752ca678be674dcbcde6c5e4874c44843a28d8
Author: Michael Johnson <email address hidden>
Date: Wed Aug 16 13:06:42 2017 -0700

    Return neutron-ns-metadata-proxy threads to 1000

    A wsgi threads change [1] also changed the number of threads the
    neutron-ns-metadata-proxy process has down to 100. At some sites this
    low setting is leading to failures.
    This patch increases only the neutron-ns-metadata-proxy default thread count
    back up to 1000 to resolve these failures.

    This is not a cherry pick from Ocata as this code was removed in Ocata
    in favor of using HAProxy with a setting of 1024 [2].

    [1] https://review.openstack.org/278007/
    [2] https://review.openstack.org/431691

    Change-Id: I59cb05e165c6daa4ce0a1b636450f66fb699e88e
    Closes-Bug: #1711215