Red Hat Ansible for Network Automation

Procedure 3.6. Instructions

1. Define interface data using variables. Define interface data for spine and leaf devices using group variables named spine_interfaces and leaf_interfaces that map interfaces by name to descriptions.

   To save typing, the files can be downloaded using wget. Download the spines and leafs group variable files:

   [student@workstation proj]$ cd group_vars
   [student@workstation group_vars]$ wget \
   > http://materials.example.com/content/ch3/lab3/group_vars/spines
   [student@workstation group_vars]$ wget \
   > http://materials.example.com/content/ch3/lab3/group_vars/leafs
   [student@workstation group_vars]$ cd ..

   [student@workstation proj]$ cat group_vars/spines
   spine_interfaces:
   - { name: eth0, description: mgmt }
   - { name: eth1, description: leaf01 }
   - { name: eth2, description: leaf02 }
   - { name: eth3, description: peer-link1 }
   - { name: eth4, description: peer-link2 }
   - { name: eth5, description: cloud-services }

   [student@workstation proj]$ cat group_vars/leafs
   leaf_interfaces:
   - { name: eth0, description: mgmt }
   - { name: eth1, description: server01 }
   - { name: eth2, description: server02 }
   - { name: eth3, description: peer-link1 }
   - { name: eth4, description: peer-link2 }
   - { name: eth5, description: spine01 }
   - { name: eth6, description: spine02 }

   Hide Solution

2. Create a playbook named spine-leaf-ifdescr.yml with plays that set interface descriptions for two host groups.

   1. Create a playbook named spine-leaf-ifdescr.yml with plays that set interface descriptions for two host groups.

      • A play that uses the spine_interface variable to set interface descriptions for the spines group.

      • A play that uses the leaf_interface variable to set interface descriptions for the leafs group.

      [student@workstation proj]$ cat spine-leaf-ifdescr.yml
      ---
      - name: set interface descriptions for spine devices
        hosts: spines
        # interface description data is in group variables file
      
        tasks:
      
        - name: set interface description
          vyos_interface:
            aggregate: "{{ spine_interfaces }}"
      
      - name: set interface descriptions for leaf devices
        hosts: leafs
        gather_facts: no
        # interface description data is in group variables file
      
        tasks:
      
        - name: set interface description
          vyos_interface:
            aggregate: "{{ leaf_interfaces }}"

      The spine and leaf devices use the same authentication credentials, so you could optionally model this using a when statement.

      [student@workstation proj]$ cat spine-leaf-ifdescr2.yml
      ---
      - name: set interface descriptions for spine and leaf devices
        hosts: vyos
        # interface description data is in group variables file
      
        tasks:
      
        - name: set interface description
          vyos_interface:
            aggregate: "{{ spine_interfaces }}"
          when: inventory_hostname in groups['spines']
      
        - name: set interface description
          vyos_interface:
            aggregate: "{{ leaf_interfaces }}"
          when: inventory_hostname in groups['leafs']

   2. Check the plays in the playbook to determine if they do what they are intended to do.

      [student@workstation proj]$ ansible-playbook --syntax-check spine-leaf-ifdescr.yml
      ...output omitted...
      [student@workstation proj]$ ansible-playbook --check spine-leaf-ifdescr.yml
      SSH password: vyos
      ...output omitted...
      [student@workstation proj]$ ansible-playbook --syntax-check spine-leaf-ifdescr2.yml
      ...output omitted...
      [student@workstation proj]$ ansible-playbook --check spine-leaf-ifdescr2.yml
      SSH password: vyos
      ...output omitted...

   Hide Solution

3. Convert the plays into roles named vyos-spine and vyos-leaf.

   1. Create appropriate directory structures.

      Create the ~/proj/roles/ directory if it does not already exist:

      [student@workstation proj]$ mkdir -p roles

      Create vyos-spine and vyos-leaf role directory structures in the ~/proj/roles/ directory using ansible-galaxy:

      [student@workstation proj]$ ansible-galaxy init roles/vyos-spine
      [student@workstation proj]$ ansible-galaxy init roles/vyos-leaf

      Hide Solution

   2. Describe the new roles and take credit for them by populating their meta/main.yml files.

      Preserve the original meta/main.yml files:

      [student@workstation proj]$ mv roles/vyos-spine/meta/main.yml \
      >  roles/vyos-spine/meta/main.yml.orig
      [student@workstation proj]$ mv roles/vyos-leaf/meta/main.yml \
      >  roles/vyos-leaf/meta/main.yml.orig

      Create new meta/main.yml files that describe the roles:

      [student@workstation proj]$ $ cat roles/vyos-spine/meta/main.yml
      ---
      galaxy_info:
        author: DO457 Student
        description: Interface descriptions for example.com VyOS spines
        company: Example, Ltd.
        license: ASL 2.0
        min_ansible_version: 2.5
        galaxy_tags:
          - acme
          - network
          - interface
      dependencies: []
      
      [student@workstation proj]$ $ cat roles/vyos-leaf/meta/main.yml
      ---
      galaxy_info:
        author: DO457 Student
        description: Interface descriptions for example.com VyOS leafs
        company: Example, Ltd.
        license: ASL 2.0
        min_ansible_version: 2.5
        galaxy_tags:
          - acme
          - network
          - interface
      dependencies: []

      Hide Solution

   3. Reproduce the play tasks as corresponding role tasks.

      Populate the roles/vyos-spine/tasks/main.yml file with tasks from the corresponding play:

      [student@workstation proj]$ cat roles/vyos-spine/tasks/main.yml
      ---
      # tasks file for vyos-spine
      - name: set interface description
        vyos_interface:
          aggregate: "{{ spine_interfaces }}"

      Populate the roles/vyos-leaf/tasks/main.yml file with tasks from the corresponding play:

      [student@workstation proj]$ cat roles/vyos-leaf/tasks/main.yml
      ---
      # tasks file for vyos-leaf
      - name: set interface description
        vyos_interface:
          aggregate: "{{ leaf_interfaces }}"

      Hide Solution

4. Create a playbook named spine-leaf-roles.yml that uses the new roles. It should contains two plays:

   • A play that maps the vyos-spine role to spines.

   • A play that maps the vyos-leaf role to leafs.

   [student@workstation proj]$ cat spine-leaf-roles.yml
   ---
   - name: Map roles to spines and leafs
     hosts: vyos
   
     tasks:
   
     - name: apply vyos-spine role to spines
       include_role:
         name: vyos-spine
       when: inventory_hostname in groups['spines']
   
     - name: apply vyos-leaf role to leafs
       include_role:
         name: vyos-leaf
       when: inventory_hostname in groups['leafs']

   Hide Solution

5. Verify that the roles work as desired.

   1. Execute ansible-playbook with the new playbook to perform the new role-based plays.

      [student@workstation proj]$ ansible-playbook spine-leaf-roles.yml
      SSH password: vyos
      ...output omitted...

      Hide Solution

   2. Execute ad hoc commands to verify that all went as expected.

      [student@workstation proj]$ ansible -m vyos_command -a "commands='sh int'" vyos
      SSH password: vyos
      ...output omitted...

      Hide Solution