Here an Ansible Playbook with three different examples how to configure Cisco router interfaces:
1. Static IP address configuration in playbook
2. Configuration comes out of Jinja2 template, can be run dynamic with variables
3. Loop in playbook configures multiple interfaces
There are some disadvantages to work with templates, if you use commands like “no shutdown” to enable the interface. They are not shown in the running-configuration which means Ansible will assume that the configuration is not matching and execute the template again.
Another disadvantage with templates is that you cannot run “before” or “after” commands to remove existing configuration all this needs to be implemented in your Jinja2 template.
Here the Ansible Playbook:
- name: Cisco interface config
connection: local
hosts: all
gather_facts: false
vars:
cli:
username: "{{ username }}"
password: "{{ password }}"
host: "{{ device_ip }}"
tasks:
- name: configure IP address
ios_config:
before:
- default interface FastEthernet1/0
lines:
- ip address 10.1.1.1 255.255.255.0
after:
- no shutdown
match: strict
parents: interface FastEthernet1/0
provider: "{{ cli }}"
- name: configure IP out of template
ios_config:
src: "interfaces.j2"
provider: "{{ cli }}"
- name: configure IP with loop
ios_config:
provider: "{{ cli }}"
before:
- "default interface {{ item.interface }}"
lines:
- "ip address {{ item.address }} 255.255.255.0"
after:
- no shutdown
parents: "interface {{ item.interface }}"
with_items:
- { interface : FastEthernet2/0, address : 10.3.3.3 }
- { interface : FastEthernet2/1, address : 10.4.4.4 }
Read my new posts about Ansible Playbook for Cisco ASAv Firewall Topology or Ansible Playbook for Cisco BGP Routing Topology.
Great stuff. You state two disadvantages of using ios_config with templates. The first disadvantage states that the idempotent functionally will be broken when using certain options in the template. Since shutdown is shown in the running config, the template can have a condition to only apply “no shutdown” if “shutdown” have been found. Would that solve the first disadvantage?
The second disadvantage can also be seen as an advantage for it keeps the configuration logic centrally in the template and reusable.
Personally I would prefer and use the Jinja2 templates because it keeps the playbook config short and the same place like you already said. But unfortunately I didn’t figure out a way how to deal with the “shutdown” and “no shutdown” scenarios. You have an idea how to solve this?
Here is how I used this in the past in my j2 templates:
{% for item in sub_interfaces %} interface Port-channel{{ item.channel }}.{{ item.vlan }} description {{ item.desc }} encapsulation dot1Q {{ item.vlan }} ip vrf forwarding {{ item.vrf }} ip address {{ item.ip }} {{ item.subnet }} no shutdown {% endfor %}