nxos_interfaces: RMB state fixes

[chrisvanheuveln]

SUMMARY

nxos_interfaces hit a number of failures in our regression testbeds. When I dug into it I found a number of issues including but not limited to:

• cross-platform issues

• different default states depending on interface types

• idempotence issues

• unnecessarily changing state on attributes that will cause churn in a network; e.g. changing description with state: replaced would result in toggling enabled off and on, even when enabled was already at the desired state.

• did not handle non-existent virtual interfaces correctly

• enable default state is dependent on device type, interface type, and the state of the system default switchport configurations. I've left comments in the code as well but I'll include them here for PR clarity. The gist is that "factory default" for enable really only applies to L3 interfaces and that system default switchport config commands define the defaults for L2 interfaces:

    L3 interfaces:
     - Most L3 intfs default to `shutdown`. Loopbacks default to `no shutdown`.
     - Some legacy platforms default L3 intfs to 'no shutdown' (e.g. N3K, N6K)
    L2:
     - An intf may be explicitly defined as L2 with 'switchport', or it may be implicitly defined
       as L2 when "User System Default" command 'system default switchport' is defined.
     - The USD configuration `system default switchport shutdown' defines the enabled state
       for L2 intf's.
     - USD defaults may be different on some platforms. Default `system default` commands may
       not display with `show run` so you need to use `show run all` to see them.

I added a fairly involved Unit Test that covers a wide variety of common scenarios and tests each of the merged/deleted/replaced/overridden states. I believe that if you review those scenarios first it will help to understand the logic I added to this module.

The changeset in this PR now passes all of the Unit Tests, and all of the regression tests are now passing on our regression testbeds: N3K/N6K/N7K/N9K/NXOSv (internal IDs: n3k-173,n6k-77,n7k-99,dt-n9k5-1,n7k-j,evergreen-nx-1,greensboro-nx-1,hamilton-nx-1,camden-nx-1)

ISSUE TYPE

• Bugfix Pull Request

COMPONENT NAME

nxos_interfaces

ADDITIONAL INFORMATION

[ansibot]

cc @NilashishC @Qalthos @danielmellado @ganeshrn @justjais @mikewiebe @rahushen @trishnaguha
click here for bot help

[ansibot]

The test ansible-test sanity --test validate-modules [explain] failed with 1 error:

lib/ansible/modules/network/nxos/nxos_interfaces.py:0:0: doc-default-does-not-match-spec: Argument 'enabled' in argument_spec found in config defines default as (False) but documentation defines default as (True)

The test ansible-test sanity --test pylint [explain] failed with 1 error:

lib/ansible/module_utils/network/nxos/config/interfaces/interfaces.py:293:4: dangerous-default-value: Dangerous default value {} as argument

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[mikewiebe]

shipit

[NilashishC]

cc @trishnaguha

[NilashishC]

recheck

[NilashishC]

Looks like CI is green on this one. Here's the result of the latest run with this PR added as a depends-on.

https://object-storage-ca-ymq-1.vexxhost.net/v1/a0b4156a37f9453eb4ec7db5422272df/ansible_42/65442/36707999cc13d951b048d574fa9c2e0c95eb1123/third-party-check/ansible-test-network-integration-nxos-cli-python36/c9f1fbf/controller/ara-report/reports/276be786-8e19-4508-93e1-f48baa3583e8.html

[NilashishC]

Looks good to me. Thanks for the fix!

[ansible-zuul]

Build succeeded (third-party-check pipeline).

• ansible-test-network-integration-nxos-cli-python36 : FAILURE in 2h 36m 51s (non-voting)

[chrisvanheuveln]

@NilashishC Please cherry-pick to 2.9.x -Thanks