Fix(eos_designs)!: VARPv6 config is not generated even when "ipv6_enable: true" is specified

[bjmeuer]

Change Summary

VARPv6 is now configured not only when "ipv6_address" is given, it also is configured if "ipv6_enable:true" is given

Related Issue(s)

Fixes #4203

Component(s) name

arista.avd.eos_designs

Proposed changes

before for VARPv6 this was checked:
if vlan_interface_config["ipv6_address"] is not None:

after the change it is:
if vlan_interface_config["ipv6_address"] is not None or vlan_interface_config["ipv6_enable"]:

How to test

tenants:
  - name: All-Switches
    mac_vrf_vni_base: 10000

    vrfs:
      - name: HOSTING
        vrf_id: 1
        mlag_ibgp_peering_vlan: 4093
        ...
        svis:
          - id: 10
            name: hosting
            tags: ['fabric']
            description: hosting SVI
            enabled: true
            ip_address_virtual: 1.1.1.1/24
            ipv6_enable: true
            ipv6_virtual_router_addresses:
              - fe80::1

Checklist

User Checklist

• N/A

Repository Checklist

• 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-4208
# Activate the virtual environment
source test-avd-pr-4208/bin/activate
# Install all requirements including PyAVD
pip install "pyavd[ansible] @ git+https://github.com/bjmeuer/avd.git@varpv6_ipv6enable#subdirectory=python-avd" --force
# Install Ansible collection
ansible-galaxy collection install git+https://github.com/bjmeuer/avd.git#/ansible_collections/arista/avd/,varpv6_ipv6enable --force
# Optional: Install AVD examples
cd test-avd-pr-4208
ansible-playbook arista.avd.install_examples

[gmuloc]

So I think we would need to adjust the schema description for the key under SVI:

                # IPv6 VARP addresses.
                # Requires an IPv6 address to be configured on the SVI.
                # If ipv6_address_virtuals is also set, ipv6_virtual_router_addresses will take precedence
                # _if_ there is an ipv6_address configured for the node.
                ipv6_virtual_router_addresses:

The second line needs to be changed. Also the fourth line is not correct anymore. Can you please adjust the documentation with what you feel makes sense?

Point of attention

Right now I feel like this Fix is a breaking change to the current behavior for at least one case, the existing behavior is that:

• If ipv6_enable is true BUT no ipv6 address is set, then ipv6_address_virtuals (Anycast IPv6 addresses) are configured, as ipv6_virtual_router_address is ignored if present.
• With your change, ipv6_virtual_router_address is not ignored anymore in this situation (which is what your fix is about) and so we would not be configuring the Anycast IPv6 addresses anymore.

From a behavior point of view it can break existing deployment where people would have both ipv6_address_virtuals and ipv6_virtual_router_address set (probably a bad input choice as one is useless today), no IPv6 address defined, and ipv6_enable: true. I know this is probably a corner case but as we are following semver this is something we need to consider.

@ClausHolbechArista for review when he is back.

[gmuloc]

The following inputs would give a different outcome before/ after the PR:

Change of behavior for ipv6_enable: true

          - id: 666
            enabled: true
            name: VARPv6_vs_AnycastV6
            ipv6_enable: true
            ipv6_virtual_addresses:
              - 2001:db8::cafe
            ipv6_virtual_router_addresses:
              - fe80::1

Bug fix where AVD is wrongly checking for ip_router_virtual_address instead of ipv6_router_virtual_addresses

With the config below, because AVD is wrongly checking for IPv4 VARP to decide or not to configure IPv6 Anycast vurtal addresses, this will generate IPv6 Anycast config before the PR but not after.

          - id: 42
            enabled: true
            name: AnycastGW_checking_v4VARP_Bug
            # the next two keys will generate the IPv4 VARP
            ip_virtual_router_addresses:
              - 10.10.10.10
            nodes:
              - node: dummy
                 ip_address: 19.168.250.5/24
            # Then because of the bug the next key will generate the Anycast IPv6 virtual IPs
            ipv6_virtual_addresses:
              - 2001:db8::cafe

[ClausHolbechArista]

We will move this to 5.0 to avoid any concerns of breaking changes. We need to add some info in the release notes to tell about the potential breakage although it is a very small risk.
Moving the PR to draft until 4.10 has been released.

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[github-actions]

Conflicts have been resolved. A maintainer will review the pull request shortly.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

done

[ClausHolbechArista]

Great test cases with good descriptions. Thank you for fixing these issues.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud