Feat(eos_designs): Accept auto as argument for rd_override and rt_override

[rrajpuro-anet]

Change Summary

This PR adds feature to use the specific keyword auto when overriding rd or rt to auto.

Related Issue(s)

Fixes #4857

Component(s) name

arista.avd.eos_designs

Proposed changes

• Tests the rd_overrride or rt_override to match the literal string auto.
• Return auto if matches

Pending changes

• Need to update documenation to following

  rt_override supports three formats:
    - A single number which will be used in the RT fields instead of mac_vrf_id/mac_vrf_vni (see 'overlay_rt_type' for details).
    - A full RT string with colon separator which will override the full RT.
    - The literal string `auto`           
  rd_override supports three formats:
    - A single number which will be used in the RD assigned number field instead of mac_vrf_id/mac_vrf_vni (see 'overlay_rd_type' for details).
    - A full RD string with colon separator which will override the full RD.
    - The literal string `auto`

• Need to write tests

• My code has been rebased from devel before I start
• I have read the CONTRIBUTING document.
• My change requires a change to the documentation and documentation have been updated accordingly.
• I have updated molecule CI testing accordingly. (check the box if not applicable)

[github-actions]

Review docs on Read the Docs

To test this pull request:

# Create virtual environment for this testing below the current directory
python -m venv test-avd-pr-4858
# Activate the virtual environment
source test-avd-pr-4858/bin/activate
# Install all requirements including PyAVD
pip install "pyavd[ansible] @ git+https://github.com/rrajpuro-anet/avd.git@devel#subdirectory=python-avd" --force
# Point Ansible collections path to the Python virtual environment
export ANSIBLE_COLLECTIONS_PATH=$VIRTUAL_ENV/ansible_collections
# Install Ansible collection
ansible-galaxy collection install git+https://github.com/rrajpuro-anet/avd.git#/ansible_collections/arista/avd/,devel --force
# Optional: Install AVD examples
cd test-avd-pr-4858
ansible-playbook arista.avd.install_examples

[ClausHolbechArista]

Please add this to molecule tests and verify the outputs are as expected.

I would suggest modifying the file ansible_collections/arista/avd/molecule/eos_designs_unit_tests/inventory/group_vars/DC1_TENANT_NETWORKS/Tenant_A.yml and add the rt / rd override on VRF Tenant_a_ERP_Zone (line 78) and the SVI 122 below that.
If this also applies to EVPN bundles, we should also add testing in ansible_collections/arista/avd/molecule/eos_designs_unit_tests/inventory/host_vars/evpn_vlan_bundle.yml where you should test it on one of the bundles (ex. bundle6 in line 162). In the same file it would also be interesting to test on vlan 20 (line 29) since it will get it's own bundle using a different code path.

After updating the files mentioned you can rerun molecule with:

cd ansible_collections/arista/avd
molecule converge -s eos_designs_unit_tests

and then inspect the changed files if you get all and only the changes you expect.

Moving this PR to draft while you work on this. Set it "ready for review" once you have addressed by comments and added test coverage.

[rrajpuro-anet]

I ran the above requested unit tests are following are my observations on setting rt and rd override:

Case1: evpn_vlan_aware_bundles: true

1. setting on vrf: overrides as expected.
2. setting on a specific bundle in evpn_vlan_bundles: overrides as expected.
3. setting on a single vlan in l2vlans: overrides only if vlans are not auto bundles based on vlan name.
4. setting on a single svi in vrfs.svis: does not override if bundles are auto generated

Case2: evpn_vlan_aware_bundles: false

1. setting on vrf: overrides as expected.
2. setting on a specific bundle in evpn_vlan_bundles: overrides as expected.
3. setting on a single vlan in l2vlans: overrides as expected.
4. setting on a single svi in vrfs.svis: overrides as expected.

In my opinion it does not make much sense to override these parameters when using vlan aware bundles or atleast when they are auto assigned.

If we agree. Please let me know what tests to add so that we can merge this feature as soon as possilbe.

NOTE: DC1_FABRIC has evpn_vlan_aware_bundles: true. The following test will not validate our requirement.

I would suggest modifying the file ansible_collections/arista/avd/molecule/eos_designs_unit_tests/inventory/group_vars/DC1_TENANT_NETWORKS/Tenant_A.yml and add the rt / rd override on VRF Tenant_a_ERP_Zone (line 78) and the SVI 122 below that.

Molecule Test commits on this branch -> https://github.com/rrajpuro-anet/avd/tree/rd-rt-override

[ClausHolbechArista]

If we agree. Please let me know what tests to add so that we can merge this feature as soon as possilbe.

Thank you for going through the tests. The tests you have comitted cover the non-bundle case. If you could add the auto variant in some bundle test as well that would be good. You don't need to add on SVI for the bundle test, but you would need to cover the three other cases since the code paths are separate. Thanks.