Patching doesn't work for systems with IPv6

[Anujeyan Manokeran]

Bug Description : Distributed cloud lab patches in software management page in horizon doesn’t have correct patch state. It says patch state n/a and progress bar is moving when there is no action in background. Attached image have more info.

[wrsroot@controller-0 ~(keystone_admin)]$ sw-patch query
      Patch ID RR Release Repo State Patch State
===================== == ======= ========== ===========
2018-10-23_01-52-00_A Y 18.10 Applied n/a
2018-10-23_01-52-00_B Y 18.10 Applied n/a
2018-10-23_01-52-00_C Y 18.10 Applied n/a

Severity
--------
Major

Steps to Reproduce
------------------
1. upload patches using horizon
2. Apply patches and check the state on horizon
Expected Behavior
------------------

Patch state

Actual Behavior
----------------
As per description

Reproducibility
---------------
100% Reproduce-able

System Configuration
--------------------
Distributed cloud

Branch/Pull Time/Commit
-----------------------
StarlingX_Upstream_build release branch build as of 2018-10-24_20-18-00

Timestamp/Logs
--------------
2018-10-26T15:01:03.000

[Ghada Khalil (gkhalil)]

From Don Penney:
the patching daemons are not properly configuring multicast on IPv6 systems, and cannot talk to each other as a result.

For IPv6 systems, patching is using the following function to determine the interface index, against which the multicast address is configured:
    import ctypes
    import ctypes.util

    libc = ctypes.CDLL(ctypes.util.find_library('c'))

    def if_nametoindex(name):
        return libc.if_nametoindex(name)

The following commit made changes to how tsconfig parses the platform.conf file:
https://github.com/openstack/stx-update/commit/a539b771cf6ba5e1e08ea388342265f839c53b3e#diff-6ba9d2507cc0d05ce908b2e52c08dee0

This results in strings now being returned as Unicode (u'eno4.160'). And the libc function used by patching doesn't handle unicode, it seems, returning 0 instead of the correct ifindex:
>>> import tsconfig.tsconfig as tsc
>>> tsc.management_interface
u'eno4.160'
>>> str(tsc.management_interface)
'eno4.160'
>>> import ctypes
>>> import ctypes.util
>>>
>>> libc = ctypes.CDLL(ctypes.util.find_library('c'))
>>> libc.if_nametoindex(tsc.management_interface)
0
>>> libc.if_nametoindex(str(tsc.management_interface))
6
>>>

In summary: patching is broken on IPv6 systems.

[Ghada Khalil (gkhalil)]

stx.2019.03 - issue was introduced by changes related to python2->python3 conversion.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/614504

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/614504
Committed: https://git.openstack.org/cgit/openstack/stx-update/commit/?id=53f6f3bcb6bf0cb90481ab5ed77b715401464900
Submitter: Zuul
Branch: master

commit 53f6f3bcb6bf0cb90481ab5ed77b715401464900
Author: Sun Austin <email address hidden>
Date: Tue Oct 30 14:08:00 2018 +0800

    Update config to set values as string, rather than unicode

    A prior update config for python2/3 compatibility resulted
    in config values being set as unicode rather than strings. This
    ended up breaking patching on IPv6 systems, as the lib,
    if_nametoindex function used by patching in configuration of its
    multicast addresses does not properly handle unicode.
    As a result, the patching daemons were unable to communicate with
    each other.

    This update to tsconfig/config casts the values as str() to
    restore it to the previous behaviour.

    Closes-Bug:1800195

    Change-Id: Ie7ac29728e81d2e5fcb80cde34d723c1480566d0
    Signed-off-by: Sun Austin <email address hidden>

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/680189

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/680189
Committed: https://git.openstack.org/cgit/starlingx/config/commit/?id=2a80bd3a31635e77d9b90859d7fdfa95b592f2af
Submitter: Zuul
Branch: master

commit 2a80bd3a31635e77d9b90859d7fdfa95b592f2af
Author: Sun Austin <email address hidden>
Date: Tue Oct 30 14:08:00 2018 +0800

    Update config to set values as string, rather than unicode

    A prior update config for python2/3 compatibility resulted
    in config values being set as unicode rather than strings. This
    ended up breaking patching on IPv6 systems, as the lib,
    if_nametoindex function used by patching in configuration of its
    multicast addresses does not properly handle unicode.
    As a result, the patching daemons were unable to communicate with
    each other.

    This update to tsconfig/config casts the values as str() to
    restore it to the previous behaviour.

    Closes-Bug:1800195

    Depends-On: Ibdae0a338a1af493ac522757b61bbd6df1da941e
    Change-Id: Ie7ac29728e81d2e5fcb80cde34d723c1480566d0
    Signed-off-by: Sun Austin <email address hidden>

[Anujeyan Manokeran (anujeyan)]

Verified in load 2019-09-05_00-10-00.