Ansible network modules and collections for Cisco, Arista and Juniper

Collections for network vendors

Network support in Ansible lives in collections, one per platform. Common ones include cisco.ios, cisco.nxos, cisco.iosxr, arista.eos, junipernetworks.junos and vyos.vyos, all built on the shared ansible.netcommon collection. Install or update them with ansible-galaxy collection install cisco.ios arista.eos junipernetworks.junos, and pin versions in a requirements.yml file so every engineer uses the same code.

Connection settings per platform

Put these in group_vars for each platform group. For enable mode on IOS and EOS, set ansible_become: true and ansible_become_method: enable. Junos devices need NETCONF over SSH enabled (set system services netconf ssh) before the netconf connection works.

Resource modules

Resource modules manage one feature as structured data, for example cisco.ios.ios_vlans, arista.eos.eos_interfaces or junipernetworks.junos.junos_vlans. The same data shape and states work across vendors, so the playbook reads like a description of intent.

- name: Standard VLANs on all access switches
  hosts: access
  gather_facts: false
  vars:
    vlans:
      - { vlan_id: 10, name: STAFF }
      - { vlan_id: 20, name: STUDENTS }
      - { vlan_id: 30, name: CCTV }
  tasks:
    - name: Ensure VLANs exist (IOS)
      cisco.ios.ios_vlans:
        config: "{{ vlans }}"
        state: merged
      when: ansible_network_os == 'cisco.ios.ios'

    - name: Ensure VLANs exist (EOS)
      arista.eos.eos_vlans:
        config: "{{ vlans }}"
        state: merged
      when: ansible_network_os == 'arista.eos.eos'

Be careful with overridden: it removes every item not in your list, so an override of VLANs could delete VLANs that other teams rely on. Use merged while you are learning and move to replaced or overridden only when your data is the trusted source of truth. The gathered state is a safe way to read current configuration as data, and rendered shows the commands a task would send without connecting to a device.

Config, command and facts modules

- name: Login banner via raw config lines
  cisco.ios.ios_config:
    lines:
      - banner motd ^Authorised access only^
    save_when: modified

- name: Read a show command
  arista.eos.eos_command:
    commands: show version
  register: ver

The *_config modules push configuration lines and check the running config to stay roughly idempotent; save_when: modified writes to startup config only when something changed. The *_command modules run show commands and never change configuration. The *_facts modules gather model, version, serial number and interfaces into variables such as ansible_net_model.

Tip: always run against a lab or a single device with --check --diff first, and confirm you have out-of-band access before changing management interfaces or ACLs remotely.