Red Hat Ansible for Network Automation

Update the host inventory to support end-to-end reachability testing. Ensure that the hosts inventory contains a group that identifies some devices as access-layer routers. Modify the inventory file so it contains content similar to the following:

[leafs]
leaf[01:02]

[spines]
spine[01:02]

[border-routers]
spine01
spine02
cs01

[access-layer]
leaf01
leaf02
cs01

[cloud-services]
cs01

[ios]
cs01

[vyos:children]
spines
leafs

[network:children]
vyos
ios

Add variables that identity ingress and egress points as source and destination for ping test. Create a variables file named vars/ping-srcdst.yml that contains this data:

pingcount: 2
ping_data:
  leaf01:
  - { src: "10.10.10.1", dst: "192.168.10.1" }
  - { src: "10.10.10.1", dst: "172.16.10.1" }
  leaf02:
  - { src: "192.168.10.1", dst: "10.10.10.1" }
  - { src: "192.168.10.1", dst: "172.16.10.1" }
  cs01:
  - { src: "172.16.10.1", dst: "10.10.10.1" }
  - { src: "172.16.10.1", dst: "192.168.10.1" }

It is possible to use Ansible and Jinja2 to automatically generate the data in this variables file, but for now we are going to keep matters as simple as possible and start with this data.

Perform a play that verifies reachability across the network on an end-to-end basis.

1. Compose a multivendor playbook that loops over the ping data tuples for each host and pings from source to destination. Include a task that loops over the result set and asserts that output from the ping test matches patterns that reliably indicate a successful test.

   Create a file named e2e.yml with content similar to the following:

   ---
   - name: verify connectivity end-to-end
     hosts: access-layer
     vars_files:
       - vars/ping-srcdst.yml
   
     tasks:
   
     - name: run ping commands on VyOS access layer device
       # this runs a ping command across the link
       vyos_command:
         commands:
         - ping {{ item.dst }} interface {{ item.src }} count {{ pingcount }}
       register: ping_result
       loop: "{{ ping_data[inventory_hostname] }}"
       when: ansible_network_os == 'vyos'
       # registering within loop associates values with varname.results
   
     - name: looped assertion of ping results from VyOS access layer device
       assert:
         that: "', 0% packet loss' in item.stdout[0]"
       loop: "{{ ping_result.results }}"
       when: ansible_network_os == 'vyos'
   
     - name: prime IOS arp cache
       ios_command:
         commands:
         - ping {{ item.dst }} source {{ item.src }} repeat 1
       loop: "{{ ping_data[inventory_hostname] }}"
       when: ansible_network_os == 'ios'
   
     - name: "run ping commands on IOS access layer device {{ inventory_hostname }}"
       ios_command:
         commands:
         - ping {{ item.dst }} source {{ item.src }} repeat {{ pingcount }}
       register: ping_result
       loop: "{{ ping_data[inventory_hostname] }}"
       when: ansible_network_os == 'ios'
   
     - name: looped assertion of ping results from IOS access layer device
       assert:
         that: "'Success rate is 100 percent' in item.stdout[0]"
       loop: "{{ ping_result.results }}"
       when: ansible_network_os == 'ios'

2. Perform the play found in your new playbook.

   [student@workstation proj]$ ansible-playbook e2e.yml

   If all goes well, the play recap should show ok=2 and failed=0 for each device.

   PLAY RECAP
   PLAY RECAP *********************************************************************
   cs01                       : ok=2    changed=0    unreachable=0    failed=0
   leaf01                     : ok=2    changed=0    unreachable=0    failed=0
   leaf02                     : ok=2    changed=0    unreachable=0    failed=0