Setting maximum paths & ecmp for eBGP in eos_l3ls_evpn role

[aphillipps]

Change Summary

In the current AVD model, the number of maximum paths and the number of ecmp paths can not be set. It is configured automatically using the number of spines in the fabric as a reference. In some design the desired maximum paths is the target number of spines from the beginning on even though spines will be added little by little. In this case, this value can be set manually in the fabric description.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Documentation content changes
• Other (please describe):

Related Issue(s)

#384

Component(s) name

eos_l3ls_evpn role

Proposed changes

The new optional keys are added in the description of the fabric as follows:

# BGP multi-path
# If not defined these values will be equal by default to the number of spines in the fabric
# If defined the values defined will both be applied to leaf and spine switches
# Note: these values are only relevant for an eBGP scenario
bgp_maximum_paths: <number_of_max_paths>
bgp_ecmp: <number_of_ecmp_paths>

How to test

Add for example the following values and keys in DC1_FABRIC.yml:

bgp_maximum_paths: 8
bgp_ecmp: 8

This will render the following structured config file (at the bottom of all the other declared bgp_defaults values):

  bgp_defaults:
    - no bgp default ipv4-unicast
    - distance bgp 20 200 200
    - graceful-restart restart-time 300
    - graceful-restart
    - maximum-paths 8 ecmp 8

If not defined, it will simply render the line above with the number of spines instead of 8.

Checklist:

• I have read the CONTRIBUTING document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• All new and existing tests passed (pre-commit, make linting and make sanity-lint).
• I have updated molecule CI testing accordingly

[titom73]

LGTM!