Prepare Fabric Configurations
NaC Introduction
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Prepare Fabric Configurations

In this section, you will learn how to prepare network configurations for the Nexus fabric using the Network as Code approach.

Step 1 - Create and Switch to a New Git Branch

To begin, return to your VS Code Terminal. You will create a new branch in Git to work from. Branching in Git is a strategy to work on your codebase without making changes in the main branch. Doing so de-risks errors and issues you could introduce into the main branch inadvertently. Given this, the main branch should never be used for development and execution against your test network. The main branch is a safe branch. If the lab allowed more time, there are additional concepts such as branch protection rules that you can explore to further protect your main branch from any use except for prod use.

To create a new branch, you can use git checkout -b where the option -b is for the new branch name.

  1. Copy and paste the below command in the VS Code Server terminal window to create and switch to a new branch.

    2. 
git checkout -b fabric-deployment

  2. Your landing page should look similar to the screenshot below with the branch created and switched successfully.


Step 2 - Create Deployment Inventory File

You will create the inventory.nac.yaml file in the data directory. This file defines the connection URL details of all the network devices in the topology, including Spine S1, S2 and Leaf L1, L2, switches using their management IPs.

  1. Copy and paste the below command in the VS Code Server terminal window to create the inventory.nac.yaml file in the data directory.

    2. 
code-server -r data/inventory.nac.yaml

  2. Copy the following code into your newly created inventory.nac.yaml file.

    3. 
---
nxos:
  devices:
    - name: S1
      url: https://10.15.103.21
    - name: S2
      url: https://10.15.103.22
    - name: L1
      url: https://10.15.103.23
    - name: L2
      url: https://10.15.103.24

  3. Press Ctrl + s to save the inventory.nac.yaml file.

    If the keyboard shortcut does not work, please open the VS Code Server hamburger menu and click File > Save.

Warning

Be sure to save your file! Not saving will result in your code not executing.


Step 3 - Create S1 (Spine-1) Switch configuration file

Create the configuration file S1.nac.yaml for Spine-1 switch (S1) in the data directory. This YAML file defines the complete configuration for the Spine-1 switch including system settings, interfaces, and BGP routing.

  1. Copy and paste the below command in the VS Code Server terminal window to create the S1.nac.yaml file in the data directory.

    2. 
code-server -r data/S1.nac.yaml

  2. Copy the following code into your newly created S1.nac.yaml file.

    3. 
---
nxos:
  devices:
    - name: S1
      url: https://10.15.103.21
      configuration:
        system:
          hostname: S1
          feature:
            bgp: true
            lldp: true
        interfaces:
          loopbacks:
            - id: 0
              ipv4_address: 10.0.0.1/32
              admin_state: true
          ethernets:
            - id: 1/1
              description: "connected to L1 Ethernet1/29"
              layer3: true
              ipv4_address: 10.1.11.1/30
              admin_state: true
            - id: 1/11
              description: "connected to L1 Ethernet1/30"
              layer3: true
              ipv4_address: 10.1.11.5/30
              admin_state: true
            - id: 1/2
              description: "connected to L2 Ethernet1/29"
              layer3: true
              ipv4_address: 10.1.12.1/30
              admin_state: true
            - id: 1/12
              description: "connected to L2 Ethernet1/30"
              layer3: true
              ipv4_address: 10.1.12.5/30
              admin_state: true
        routing:
          ipv4_prefix_lists:
            - name: REDISTRIBUTE_PREFIXES
              entries:
                - order: 10
                  action: permit
                  prefix: 10.0.0.1/32
                  criteria: exact
          route_maps:
            - name: fabric-rmap-redist-subnet
              entries:
                - order: 10
                  action: permit
                  match_prefix_list: REDISTRIBUTE_PREFIXES
          bgp:
            asn: "65535"
            vrfs:
              - vrf: default
                router_id: 10.0.0.1
                address_families:
                  - address_family: ipv4_unicast
                    max_ecmp_paths: 4
                    redistributions:
                      - protocol: direct
                        protocol_instance: "none"
                        route_map: fabric-rmap-redist-subnet
                neighbors:
                  - ip: 10.1.11.2
                    asn: "65011"
                    description: "L1-Eth1/29"
                    source_interface: eth1/1
                    address_families:
                      - address_family: ipv4_unicast
                  - ip: 10.1.11.6
                    asn: "65011"
                    description: "L1-Eth1/30"
                    source_interface: eth1/11
                    address_families:
                      - address_family: ipv4_unicast
                  - ip: 10.1.12.2
                    asn: "65012"
                    description: "L2-Eth1/29"
                    source_interface: eth1/2
                    address_families:
                      - address_family: ipv4_unicast
                  - ip: 10.1.12.6
                    asn: "65012"
                    description: "L2-Eth1/30"
                    source_interface: eth1/12
                    address_families:
                      - address_family: ipv4_unicast

  3. Press Ctrl + s to save the S1.nac.yaml file.

    If the keyboard shortcut does not work, please open the VS Code Server hamburger menu and click File > Save.

Warning

Be sure to save your file! Not saving will result in your code not executing.


Step 4 - Create S2 (Spine-2) Switch configuration file

Create the configuration file S2.nac.yaml for Spine-2 switch (S2) in the data directory. This YAML file defines the complete configuration for the Spine-2 switch including system settings, interfaces, and BGP routing.

  1. Copy and paste the below command in the VS Code Server terminal window to create the S2.nac.yaml file in the data directory.

    2. 
code-server -r data/S2.nac.yaml

  2. Copy the following code into your newly created S2.nac.yaml file.

    3. 
---
nxos:
  devices:
    - name: S2
      url: https://10.15.103.22
      configuration:
        system:
          hostname: S2
          feature:
            bgp: true
            lldp: true
        interfaces:
          loopbacks:
            - id: 0
              ipv4_address: 10.0.0.2/32
              admin_state: true
          ethernets:
            - id: 1/1
              description: "connected to L1 Ethernet1/31"
              layer3: true
              ipv4_address: 10.1.21.1/30
              admin_state: true
            - id: 1/11
              description: "connected to L1 Ethernet1/32"
              layer3: true
              ipv4_address: 10.1.21.5/30
              admin_state: true
            - id: 1/2
              description: "connected to L2 Ethernet1/31"
              layer3: true
              ipv4_address: 10.1.22.1/30
              admin_state: true
            - id: 1/12
              description: "connected to L2 Ethernet1/32"
              layer3: true
              ipv4_address: 10.1.22.5/30
              admin_state: true
        routing:
          ipv4_prefix_lists:
            - name: REDISTRIBUTE_PREFIXES
              entries:
                - order: 10
                  action: permit
                  prefix: 10.0.0.2/32
                  criteria: exact
          route_maps:
            - name: fabric-rmap-redist-subnet
              entries:
                - order: 10
                  action: permit
                  match_prefix_list: REDISTRIBUTE_PREFIXES
          bgp:
            asn: "65535"
            vrfs:
              - vrf: default
                router_id: 10.0.0.2
                address_families:
                  - address_family: ipv4_unicast
                    max_ecmp_paths: 4
                    redistributions:
                      - protocol: direct
                        protocol_instance: "none"
                        route_map: fabric-rmap-redist-subnet
                neighbors:
                  - ip: 10.1.21.2
                    asn: "65011"
                    description: "L1-Eth1/31"
                    source_interface: eth1/1
                    address_families:
                      - address_family: ipv4_unicast
                  - ip: 10.1.21.6
                    asn: "65011"
                    description: "L1-Eth1/32"
                    source_interface: eth1/11
                    address_families:
                      - address_family: ipv4_unicast
                  - ip: 10.1.22.2
                    asn: "65012"
                    description: "L2-Eth1/31"
                    source_interface: eth1/2
                    address_families:
                      - address_family: ipv4_unicast
                  - ip: 10.1.22.6
                    asn: "65012"
                    description: "L2-Eth1/32"
                    source_interface: eth1/12
                    address_families:
                      - address_family: ipv4_unicast

  3. Press Ctrl + s to save the S2.nac.yaml file.

    If the keyboard shortcut does not work, please open the VS Code Server hamburger menu and click File > Save.

Warning

Be sure to save your file! Not saving will result in your code not executing.


Step 5 - Create L1 (Leaf-1) Switch configuration file

Create the configuration file L1.nac.yaml for Leaf-1 switch (L1) in the data directory. This YAML file defines the complete configuration for the Leaf-1 switch including system settings, VLANs, interfaces, and BGP routing.

  1. Copy and paste the below command in the VS Code Server terminal window to create the L1.nac.yaml file in the data directory.

    2. 
code-server -r data/L1.nac.yaml

  2. Copy the following code into your newly created L1.nac.yaml file.

    3. 
---
nxos:
  devices:
    - name: L1
      url: https://10.15.103.23
      configuration:
        system:
          hostname: L1
          feature:
            bgp: true
            interface_vlan: true
            lldp: true
        vlans:
          - id: 101
            name: VLAN101
        interfaces:
          loopbacks:
            - id: 0
              ipv4_address: 10.0.1.1/32
              admin_state: true
          vlans:
            - id: 101
              description: "SVI for VLAN 101"
              ipv4_address: 10.254.101.1/24
              admin_state: true
          ethernets:
            - id: 1/1
              description: "host1-ens2"
              access_vlan: 101
              admin_state: true
            - id: 1/2
              description: "host2-ens2"
              access_vlan: 101
              admin_state: true
            - id: 1/29
              description: "connected to S1 Ethernet1/1"
              layer3: true
              ipv4_address: 10.1.11.2/30
              admin_state: true
            - id: 1/30
              description: "connected to S1 Ethernet1/11"
              layer3: true
              ipv4_address: 10.1.11.6/30
              admin_state: true
            - id: 1/31
              description: "connected to S2 Ethernet1/1"
              layer3: true
              ipv4_address: 10.1.21.2/30
              admin_state: true
            - id: 1/32
              description: "connected to S2 Ethernet1/11"
              layer3: true
              ipv4_address: 10.1.21.6/30
              admin_state: true
        routing:
          ipv4_prefix_lists:
            - name: REDISTRIBUTE_PREFIXES
              entries:
                - order: 10
                  action: permit
                  prefix: 10.0.1.1/32
                  criteria: exact
                - order: 20
                  action: permit
                  prefix: 10.254.101.0/24
                  criteria: exact
          route_maps:
            - name: fabric-rmap-redist-subnet
              entries:
                - order: 10
                  action: permit
                  match_prefix_list: REDISTRIBUTE_PREFIXES
          bgp:
            asn: "65011"
            vrfs:
              - vrf: default
                router_id: 10.0.1.1
                address_families:
                  - address_family: ipv4_unicast
                    max_ecmp_paths: 4
                    redistributions:
                      - protocol: direct
                        protocol_instance: "none"
                        route_map: fabric-rmap-redist-subnet
                neighbors:
                  - ip: 10.1.11.1
                    asn: "65535"
                    description: "S1-Eth1/1"
                    source_interface: eth1/29
                    address_families:
                      - address_family: ipv4_unicast
                  - ip: 10.1.11.5
                    asn: "65535"
                    description: "S1-Eth1/11"
                    source_interface: eth1/30
                    address_families:
                      - address_family: ipv4_unicast
                  - ip: 10.1.21.1
                    asn: "65535"
                    description: "S2-Eth1/1"
                    source_interface: eth1/31
                    address_families:
                      - address_family: ipv4_unicast
                  - ip: 10.1.21.5
                    asn: "65535"
                    description: "S2-Eth1/11"
                    source_interface: eth1/32
                    address_families:
                      - address_family: ipv4_unicast

  3. Press Ctrl + s to save the L1.nac.yaml file.

    If the keyboard shortcut does not work, please open the VS Code Server hamburger menu and click File > Save.

Warning

Be sure to save your file! Not saving will result in your code not executing.


Step 6 - Create L2 (Leaf-2) Switch configuration file

Create the configuration file L2.nac.yaml for Leaf-2 switch (L2) in the data directory. This YAML file defines the complete configuration for the Leaf-2 switch including system settings, VLANs, interfaces, and BGP routing.

  1. Copy and paste the below command in the VS Code Server terminal window to create the L2.nac.yaml file in the data directory.

    2. 
code-server -r data/L2.nac.yaml

  2. Copy the following code into your newly created L2.nac.yaml file.

    3. 
---
nxos:
  devices:
    - name: L2
      url: https://10.15.103.24
      configuration:
        system:
          hostname: L2
          feature:
            bgp: true
            interface_vlan: true
            lldp: true
        vlans:
          - id: 102
            name: VLAN102
        interfaces:
          loopbacks:
            - id: 0
              ipv4_address: 10.0.2.2/32
              admin_state: true
          vlans:
            - id: 102
              description: "SVI for VLAN 102"
              ipv4_address: 10.254.102.1/24
              admin_state: true
          ethernets:
            - id: 1/1
              description: "host1-ens3"
              access_vlan: 102
              admin_state: true
            - id: 1/2
              description: "host2-ens3"
              access_vlan: 102
              admin_state: true
            - id: 1/29
              description: "connected to S1 Ethernet1/2"
              layer3: true
              ipv4_address: 10.1.12.2/30
              admin_state: true
            - id: 1/30
              description: "connected to S1 Ethernet1/12"
              layer3: true
              ipv4_address: 10.1.12.6/30
              admin_state: true
            - id: 1/31
              description: "connected to S2 Ethernet1/2"
              layer3: true
              ipv4_address: 10.1.22.2/30
              admin_state: true
            - id: 1/32
              description: "connected to S2 Ethernet1/12"
              layer3: true
              ipv4_address: 10.1.22.6/30
              admin_state: true
        routing:
          ipv4_prefix_lists:
            - name: REDISTRIBUTE_PREFIXES
              entries:
                - order: 10
                  action: permit
                  prefix: 10.0.2.2/32
                  criteria: exact
                - order: 20
                  action: permit
                  prefix: 10.254.102.0/24
                  criteria: exact
          route_maps:
            - name: fabric-rmap-redist-subnet
              entries:
                - order: 10
                  action: permit
                  match_prefix_list: REDISTRIBUTE_PREFIXES
          bgp:
            asn: "65012"
            vrfs:
              - vrf: default
                router_id: 10.0.2.2
                address_families:
                  - address_family: ipv4_unicast
                    max_ecmp_paths: 4
                    redistributions:
                      - protocol: direct
                        protocol_instance: "none"
                        route_map: fabric-rmap-redist-subnet
                neighbors:
                  - ip: 10.1.12.1
                    asn: "65535"
                    description: "S1-Eth1/2"
                    source_interface: eth1/29
                    address_families:
                      - address_family: ipv4_unicast
                  - ip: 10.1.12.5
                    asn: "65535"
                    description: "S1-Eth1/12"
                    source_interface: eth1/30
                    address_families:
                      - address_family: ipv4_unicast
                  - ip: 10.1.22.1
                    asn: "65535"
                    description: "S2-Eth1/2"
                    source_interface: eth1/31
                    address_families:
                      - address_family: ipv4_unicast
                  - ip: 10.1.22.5
                    asn: "65535"
                    description: "S2-Eth1/12"
                    source_interface: eth1/32
                    address_families:
                      - address_family: ipv4_unicast

  3. Press Ctrl + s to save the L2.nac.yaml file.

    If the keyboard shortcut does not work, please open the VS Code Server hamburger menu and click File > Save.

Warning

Be sure to save your file! Not saving will result in your code not executing.


Step 7 - Verify Configuration Files

After creating all the configuration files, your VS Code landing page should look similar to the screenshot below, showing the new branch and all the YAML configuration files you created in the data directory.


Continue to the next section to create the .gitlab-ci.yml file and run these Nexus deployment configurations in a pipeline.