Red Hat Ansible for Network Automation

Procedure 3.5. Instructions

1. Create a data variable that maps names to IP addresses. Download the host-objects.yml file into the vars subdirectory:

   [student@workstation proj]$ mkdir -p vars
   [student@workstation proj]$ cd vars
   [student@workstation vars]$ wget \
   > http://materials.example.com/full/vars/host-objects.yml
   [student@workstation vars]$ cd ..
   [student@workstation proj]$ cat vars/host-objects.yml
   host_object_data:
   - { name: spine01, ipv4: 10.0.0.1/32 }
   - { name: spine02, ipv4: 10.0.0.11/32 }
   - { name: leaf01, ipv4: 192.168.0.1/32 }
   - { name: leaf02, ipv4: 192.168.0.2/32 }
   - { name: cs01, ipv4: 172.16.0.1/32 }
   - { name: server01, ipv4: 10.10.10.2 }
   - { name: server02, ipv4: 192.168.10.2 }
   - { name: server03, ipv4: 172.16.10.2 }

2. Create a Jinja2 template that loops over the data, generating an IOS ip host command for each row of data. Create a file named j2/ios-host-objects.j2 with the following content:

   {% for obj in host_object_data %}
   ip host {{ obj.name }} {{ obj.ipv4 | ipaddr('address') }}
   {% endfor %}

3. Write a play that uses the template module and connection method local to write the set of commands generated by your Jinja2 template to a file. Create a playbook named j2test-ios-host-objects.yml that defines a task that dumps text from your Jinja2 template out to a file named out/ios-host-objects.cmd. The playbook should look similar to the following:

   ---
   - name: build a file containing IOS static host object statements
     hosts: localhost
     connection: local
     vars:
       srcfile: j2/ios-host-objects.j2
       destfile: out/ios-host-objects.cmd
     vars_files:
     - vars/host-objects.yml
   
     tasks:
   
     - name: dump output from template to a file
       template:
         src: "{{ srcfile }}"
         dest: "{{ destfile }}"

4. Before you run the play, create the out directory that will hold the file created by the template module:

   [student@workstation proj]$ mkdir out
   [student@workstation proj]$ echo 'directory for generated output' > out/README

   Run the play found in your new playbook. Type any text when prompted for a password, because it is not used.

   [student@workstation proj]$ ansible-playbook j2test-ios-host-objects.yml
   SSH password: anything

5. View the output file containing the generated list of IOS ip host commands:

   [student@workstation proj]$ cat out/ios-host-objects.cmd
   ip host spine01 10.0.0.1
   ip host spine02 10.0.0.11
   ip host leaf01 192.168.0.1
   ip host leaf02 192.168.0.2
   ip host cs01 172.16.0.1
   ip host server01 10.10.10.2
   ip host server02 192.168.10.2
   ip host server03 172.16.10.2

6. Write a play that uses the ios_config module (connection method network_cli) to configure IOS devices directly from the set of commands generated by your Jinja2 template.

   1. Create a playbook named ios-host-objects.yml. It uses the src attribute of the ios_config module to source the config lines directly from the Jinja2 template: The ios-host-objects.yml playbook must include the following:

      ---
      - name: build a file containing IOS static host object statements
        hosts: ios
        vars:
          srcfile: j2/ios-host-objects.j2
        vars_files:
          - vars/host-objects.yml
      
        tasks:
          - name: configure directly from template
            ios_config:
              src: "{{ srcfile }}"
            when: ansible_network_os == 'ios'

   2. Run the play, and this time specify student as the SSH password.

      [student@workstation proj]$ ansible-playbook ios-host-objects.yml
      SSH password: student

   3. Execute an ad hoc command to confirm that the change was successful:

      [student@workstation proj]$ ansible -m ios_command \
      > -a "commands='sh run | include ip host'" cs01
      SSH password: student
      cs01 | SUCCESS => {
          "changed": false,
          "stdout": [
              "ip host cs01 172.16.0.1\nip host leaf01 192.168.0.1\nip
              host leaf02 192.168.0.2\nip host server01 10.10.10.2\nip host
              server02 192.168.10.2\nip host server03 172.16.10.2 ip host
              spine01 10.0.0.1\nip host spine02 10.0.0.11\n"
          ],
          "stdout_lines": [
              [
                  "ip host cs01 172.16.0.1",
                  "ip host leaf01 192.168.0.1",
                  "ip host leaf02 192.168.0.2",
                  "ip host server01 10.10.10.2",
                  "ip host server02 192.168.10.2",
                  "ip host server03 172.16.10.2"
                  "ip host spine01 10.0.0.1",
                  "ip host spine02 10.0.0.11",
              ]
          ]
      }