18.4. Configuring an Ethernet connection with a dynamic IP address by using the network RHEL system role with a device path
By using the network RHEL system role, you can configure an Ethernet connection to retrieve its IP addresses, gateways, and DNS settings from a DHCP server and IPv6 stateless address autoconfiguration (SLAAC). The role can assign the profile by the device’s path.
To connect a Red Hat Enterprise Linux host to an Ethernet network, create a NetworkManager connection profile for the network device. By using Ansible and the network RHEL system role, you can automate this process and remotely configure connection profiles on the hosts defined in a playbook.
Prerequisites
- You have prepared the control node and the managed nodes.
- You are logged in to the control node as a user who can run playbooks on the managed nodes.
-
The account you use to connect to the managed nodes has
sudopermissions for these nodes. - A physical or virtual Ethernet device exists in the server’s configuration.
- A DHCP server and SLAAC are available in the network.
- The managed hosts use NetworkManager to configure the network.
-
You know the path of the device. You can display the device path by using the
udevadm info /sys/class/net/<device_name> | grep ID_PATH=command.
Procedure
Create a playbook file, for example,
~/playbook.yml, with the following content:--- - name: Configure the network hosts: managed-node-01.example.com tasks: - name: Ethernet connection profile with dynamic IP address settings ansible.builtin.include_role: name: redhat.rhel_system_roles.network vars: network_connections: - name: example match: path: - pci-0000:00:0[1-3].0 - '&!pci-0000:00:02.0' type: ethernet autoconnect: yes ip: dhcp4: yes auto6: yes state: upThe settings specified in the example playbook include the following:
match: path-
Defines that a condition must be met in order to apply the settings. You can only use this variable with the
pathoption. path: <path_and_expressions>-
Defines the persistent path of a device. You can set it as a fixed path or an expression. Its value can contain modifiers and wildcards. The example applies the settings to devices that match PCI ID
0000:00:0[1-3].0, but not0000:00:02.0. dhcp4: yes- Enables automatic IPv4 address assignment from DHCP, PPP, or similar services.
auto6: yes-
Enables IPv6 auto-configuration. By default, NetworkManager uses Router Advertisements. If the router announces the
managedflag, NetworkManager requests an IPv6 address and prefix from a DHCPv6 server.
For details about all variables used in the playbook, see the
/usr/share/ansible/roles/rhel-system-roles.network/README.mdfile on the control node.Validate the playbook syntax:
$ ansible-playbook --syntax-check ~/playbook.ymlNote that this command only validates the syntax and does not protect against a wrong but valid configuration.
Run the playbook:
$ ansible-playbook ~/playbook.yml
Verification
Query the Ansible facts of the managed node and verify that the interface received IP addresses and DNS settings:
# ansible managed-node-01.example.com -m ansible.builtin.setup ... "ansible_default_ipv4": { "address": "192.0.2.1", "alias": "enp1s0", "broadcast": "192.0.2.255", "gateway": "192.0.2.254", "interface": "enp1s0", "macaddress": "52:54:00:17:b8:b6", "mtu": 1500, "netmask": "255.255.255.0", "network": "192.0.2.0", "prefix": "24", "type": "ether" }, "ansible_default_ipv6": { "address": "2001:db8:1::1", "gateway": "2001:db8:1::fffe", "interface": "enp1s0", "macaddress": "52:54:00:17:b8:b6", "mtu": 1500, "prefix": "64", "scope": "global", "type": "ether" }, ... "ansible_dns": { "nameservers": [ "192.0.2.1", "2001:db8:1::ffbb" ], "search": [ "example.com" ] }, ...