Exercise: Managing network configuration

Managing network configuration

• Configure a network interface with the network system role.
• Read network facts.

Prerequisites: Complete control-node setup and the preceding lessons in this chapter. Run commands as student on workstation unless a step names another machine.

From the project directory, run the relevant home-lab check. For an exercise with several checkpoints, grade each state before changing or removing it:

lab grade system-network

The grader reads project files and host state. A passing report covers the listed checks; also perform the task’s independent connection, repeat-run, and reboot checks where requested.

Change the dummy interface address to another documentation address, then verify the old address is gone.

Record the published result first. The grader checks the original requirements, so a changed name or value may intentionally fail those checks.

Add a persistent secondary connection on servera with playbook.yml, without interrupting its management connection.

• Use the network system role, with the connection values stored in group_vars/webservers/network.yml.
• In the classroom, use eth1 at 172.25.250.30/24. At home, use the dummy connection named eth1 at 192.0.2.30/24.
• get-eth1.yml must report the resulting interface facts.
• Verify the address, active connection, and continued SSH access, including after an explicit reboot.

The home-lab VMs have one network card, which Ansible uses. Instead of a second card, eth1 is a dummy interface, created by the same role from type: dummy, with an address from 192.0.2.0/24, a range reserved for documentation. Everything else is the same.

Install the collection

[student@workstation ~]$ cd ~/system-network
[student@workstation system-network]$ ansible-galaxy collection install \
> ./redhat-rhel_system_roles-1.120.5.tar.gz -p collections
...output omitted...
redhat.rhel_system_roles:1.120.5 was installed successfully

Write the playbook

---
- name: NIC Configuration
  hosts: webservers

  roles:
    - redhat.rhel_system_roles.network

Find the variable in the documentation

The role's README.md has a section for each kind of setting. Look for "Setting the IP configuration":

[student@workstation system-network]$ less \
> collections/ansible_collections/redhat/rhel_system_roles/roles/network/README.md

Its example shows a network_connections entry with an ip dictionary, whose address is a list of addresses with their prefix.

Put the setting in group_vars

[student@workstation system-network]$ mkdir -pv group_vars/webservers
mkdir: created directory 'group_vars'
mkdir: created directory 'group_vars/webservers'

---
network_connections:
  - name: eth1
    type: ethernet
    ip:
      address:
        - 172.25.250.30/24

---
network_connections:
  - name: eth1
    type: dummy
    interface_name: eth1
    ip:
      address:
        - 192.0.2.30/24

Run it

[student@workstation system-network]$ ansible-navigator run -m stdout playbook.yml
...output omitted...
TASK [redhat.rhel_system_roles.network : Print network provider] ***************
ok: [servera.lab.example.com] => {
    "msg": "Using network provider: nm"
}
...output omitted...
TASK [redhat.rhel_system_roles.network : Configure networking connection profiles] ***
changed: [servera.lab.example.com]
...output omitted...
ok: [servera.lab.example.com] => {
    "__network_connections_result.stderr_lines": [
        "[002] <info>  #0, state:None persistent_state:present, 'eth1': add connection eth1, 08b92940-ef4a-49ad-a309-e4f05eae64af"
    ]
}
...output omitted...
TASK [redhat.rhel_system_roles.network : Re-test connectivity] *****************
ok: [servera.lab.example.com]
...output omitted...

The role uses NetworkManager (nm), added a connection profile called eth1, and finally checked that it can still reach the host.

Read it back from the facts

---
- name: Obtain network info for webservers
  hosts: webservers

  tasks:
    - name: Display eth1 info
      ansible.builtin.debug:
        var: ansible_facts['eth1']['ipv4']

[student@workstation system-network]$ ansible-navigator run -m stdout get-eth1.yml
...output omitted...
TASK [Display eth1 info] *******************************************************
ok: [servera.lab.example.com] => {
    "ansible_facts['eth1']['ipv4']": {
        "address": "192.0.2.30",
        "broadcast": "192.0.2.255",
        "netmask": "255.255.255.0",
        "network": "192.0.2.0",
        "prefix": "24"
    }
}
...output omitted...

In a classroom, the address is 172.25.250.30.

Finish

Check your work with lab grade system-network, then put the exercise away with lab finish system-network.