Deduplication

The --dedup flag extracts common configuration into group_vars/, reducing repetition and following Ansible best practices.

Usage

netmodel export @all -i inventory.yaml -o ./network-model/ --structure ansible --dedup

How It Works

netmodel compares all exported configs and extracts:

• group_vars/all.yaml — Config identical across ALL devices
• group_vars/<group>.yaml — Config identical within inventory groups
• host_vars/<device>/ — Device-specific config only

Before vs After

Without --dedup: Everything duplicated in each host

host_vars/
├── leaf1/
│   ├── bgp.yaml         # peer_groups, neighbors, global
│   ├── system.yaml      # hostname, NTP, DNS, AAA
│   └── routing_policy.yaml
├── leaf2/
│   ├── bgp.yaml         # same peer_groups duplicated!
│   ├── system.yaml      # same NTP/DNS/AAA duplicated!
│   └── routing_policy.yaml

With --dedup: Common config extracted, DRY principle applied

group_vars/
├── all.yaml             # NTP, DNS, AAA (common to ALL devices)
├── spine.yaml           # Spine-only peer groups, policies
└── leaf.yaml            # Leaf-only peer groups, policies
host_vars/
├── leaf1/
│   ├── bgp.yaml         # Just: router_id, neighbors
│   └── interfaces.yaml
├── leaf2/
│   └── ...              # Much smaller!

What Gets Deduplicated

Config is compared at the “natural config object” level:

Stays in host_vars

These are inherently device-specific and always stay in host_vars/:

• Interfaces — different names, IPs per device
• BGP neighbors — different peer IPs
• BGP global — router_id differs
• OSPF areas — area assignments vary

Example Output

group_vars/leaf.yaml — extracted automatically:

bgp:
  peer_groups:
    SPINE:
      peer_as: 65000
      afi_safi:
        - name: IPV4_UNICAST
    SPINE-EVPN:
      peer_as: 65000
      update_source: Loopback0
      ebgp_multihop: 3
      afi_safi:
        - name: L2VPN_EVPN
routing_policy:
  defined_sets:
    prefix_sets:
      - name: LOOPBACKS
        prefixes:
          - prefix: 10.255.0.0/16
            mask_range: 16..32
system:
  aaa:
    users:
      - username: admin
        role: network-admin

host_vars/leaf1/bgp.yaml — only device-specific:

bgp:
  global:
    as: 65001
    router_id: 10.255.1.1
  neighbors:
    10.0.0.0:
      peer_group: SPINE
    10.0.0.4:
      peer_group: SPINE
    10.255.0.1:
      peer_group: SPINE-EVPN
    10.255.0.2:
      peer_group: SPINE-EVPN

Note: afi_safi isn’t repeated on neighbors — it’s inherited from the peer group.

Inventory Groups

Dedup uses your inventory groups to extract group-level common config:

# inventory.yaml
groups:
  spine:
    - spine1
    - spine2
  leaf:
    - leaf1
    - leaf2

Config common to all spines → group_vars/spine.yaml
Config common to all leaves → group_vars/leaf.yaml
Config common to everyone → group_vars/all.yaml

Try It

# Clone the test lab
git clone https://github.com/ndtobs/network-labs.git
cd network-labs/evpn-spine-leaf
sudo clab deploy -t topology.yaml

# Wait ~90s, then export both ways
netmodel export @all -i inventory.yaml -o /tmp/no-dedup --structure ansible
netmodel export @all -i inventory.yaml -o /tmp/with-dedup --structure ansible --dedup

# Compare
tree /tmp/no-dedup /tmp/with-dedup
diff /tmp/no-dedup/host_vars/leaf1/bgp.yaml /tmp/with-dedup/host_vars/leaf1/bgp.yaml
cat /tmp/with-dedup/group_vars/leaf.yaml