How it works...

We created another dictionary data structure in the core.yml file that describes the L3 links between the core switches and the WAN routers. We specified whether they will run OSPF and what the OSPF metric is on these links.

Currently, Ansible doesn't provide a declarative module to manage OSPF configuration on IOS-based devices. Therefore, we need to push the required configuration using the ios_config module. We created two separate tasks using ios_config in order to push the OSPF-related configuration on each device. In the first task, we configured the interface-related parameters under each interface, and we looped over both the svi_interface and core_l3_interfaces data structures to enable OSPF on all the OSPF-enabled interfaces. We used the Jinja2 selectattr filter to select all the interfaces that have the OSPF attribute set to yes/true.

In the last task, we applied the passive interface configuration to all the interfaces that have the passive flag enabled on them. We used the Jinja2 selectattr filter to select only those interfaces with the passive parameter set to yes/true.