Ansible Interfaces Role

An ansible role for configuring different network interfaces.

WARNING: This role can be dangerous to use. If you lose network connectivity to your target host by incorrectly configuring your networking, you may be unable to recover without physical access to the machine.

• Ethernet interfaces
• Bridge interfaces
• Bonded interfaces
• Network routes
• IP routing tables
• IP routing rules

Role Variables

The variables that can be passed to this role and a brief description about them are as follows:

# The list of route tables to be defined
interfaces_route_tables: []

# The list of ethernet interfaces to be added to the system
interfaces_ether_interfaces: []

# The list of bridge interfaces to be added to the system
interfaces_bridge_interfaces: []

# The list of bonded interfaces to be added to the system
interfaces_bond_interfaces: []

# An optional filter parameter to pass to the setup module.
interfaces_setup_filter: "{{ omit }}"

# An optional gather_subset parameter to pass to the setup module.
interfaces_setup_gather_subset: "{{ omit }}"

# An option to merge all configurations setup with merge: true
# in the global interfaces file (Debian-Family only)
interfaces_merge: false

Note: The values for the list are listed in the examples below.

1. Configure eth1 and eth2 on a host with a static IP and a dhcp IP. Also define static routes and a gateway.

- hosts: myhost
  roles:
    - role: MichaelRigart.interfaces
      interfaces_ether_interfaces:
       - device: eth1
         bootproto: static
         address: 192.168.1.150
         netmask: 255.255.255.0
         gateway: 192.168.1.1
         dnsnameservers: 192.0.2.1 192.0.2.2
         dnssearch: example.com
         mtu: 9000
         pre_up: sleep 5
         route:
          - network: 192.168.200.0
            netmask: 255.255.255.0
            gateway: 192.168.1.1
          - network: 192.168.100.0
            netmask: 255.255.255.0
            gateway: 192.168.1.1
       - device: eth2
         bootproto: dhcp

2. Configure a bridge interface with multiple NICs added to the bridge.

- hosts: myhost
  roles:
    - role: MichaelRigart.interfaces
      interfaces_bridge_interfaces:
       -  device: br1
          type: bridge
          address: 192.168.1.150
          netmask: 255.255.255.0
          bootproto: static
          stp: "on"
          mtu: 1500
          ports: [eth1, eth2]

Note: Routes can also be added for this interface in the same way routes are added for ethernet interfaces.

3. Configure a bond interface with an "active-backup" slave configuration.

- hosts: myhost
  roles:
    - role: MichaelRigart.interfaces
      interfaces_bond_interfaces:
        - device: bond0
          mtu: 9000
          address: 192.168.1.150
          netmask: 255.255.255.0
          bootproto: static
          bond_mode: active-backup
          bond_miimon: 100
          bond_slaves: [eth1, eth2]
          route:
          - network: 192.168.222.0
            netmask: 255.255.255.0
            gateway: 192.168.1.1

4. Configure a bonded interface with "802.3ad" as the bonding mode, specify the 802.3ad aggregation selection logic to use the aggregator with largest aggregate bandwidth, and IP address obtained via DHCP.

- hosts: myhost
  roles:
    - role: MichaelRigart.interfaces
      interfaces_bond_interfaces:
        - device: bond0
          bootproto: dhcp
          bond_mode: 802.3ad
          bond_ad_select: bandwidth
          bond_miimon: 100
          bond_downdelay: 200
          bond_updelay: 200
          bond_lacp_rate: 1
          bond_xmit_hash_policy: layer3+4
          bond_slaves: [eth1, eth2]

5. Configure a routing table myroutetable, and an Ethernet interface eth1 with an IP routing rule that defines when to use the routing table. It also configures an IP route on the interface for the myroutetable routing table.

- hosts: myhost
  roles:
    - role: MichaelRigart.interfaces
      interfaces_route_tables:
       - name: myroutetable
         id: 42
      interfaces_ether_interfaces:
       - device: eth1
         bootproto: static
         address: 192.168.1.150
         netmask: 255.255.255.0
         dnsnameservers: 192.0.2.1 192.0.2.2
         dnssearch: example.com
         mtu: 9000
         route:
          - network: 192.168.200.0
            netmask: 255.255.255.0
            gateway: 192.168.1.1
            table: myroutetable
         rules:
          - from 192.168.200.0/24 table myroutetable

6. Configure a hot-pluggable Wifi interface wlan0 with a static IP and a wpa_supplicant configuration. Also configure eth0 with a dhcp IP.

- hosts: myhost
  roles:
    - role: MichaelRigart.interfaces
      interfaces_ether_interfaces:
        - device: wlan0
          allowclass: allow-hotplug
          bootproto: static
          address: 192.168.1.150
          netmask: 255.255.255.0
          network: 192.168.1.0
          broadcast: 192.168.1.255
          gateway: 192.168.1.1
          dnsnameservers: 192.168.1.1
          wpaconf: /etc/wpa_supplicant/wpa_supplicant.conf
        - device: eth0
          bootproto: dhcp

7. Configure a static IPv4 address, route along with an IPv6 address and route on an interface.

- hosts: myhost
  roles:
    - role: MichaelRigart.interfaces
      interfaces_ether_interfaces:
        - device: ens160
          bootproto: static
          address: 10.99.99.2
          netmask: 255.255.255.0
          route:
            - network: 10.99.98.0
              netmask: 255.255.255.0
              gateway: 10.99.99.1
          ip6:
            address: fd49:f9f5:ccb4:2acd::ac18:1002
            prefix: 120
            route:
              - network: 64:FF9B::/96
                gateway: fd49:f9f5:ccb4:2acd::ac18:1001

8. All the above examples show how to configure a single host, The below example shows how to define your network configurations for all your machines.

Assume your host inventory is as follows:

/etc/ansible/hosts

[dc1]
host1
host2

Describe your network configuration for each host in host vars:

host_vars/host1

interfaces_ether_interfaces:
  - device: eth1
    bootproto: static
    address: 192.168.1.150
    netmask: 255.255.255.0
    gateway: 192.168.1.1
    route:
     - network: 192.168.200.0
       netmask: 255.255.255.0
       gateway: 192.168.1.1
interfaces_bond_interfaces:
  - device: bond0
    mtu: 9000
    bootproto: dhcp
    bond_mode: 802.3ad
    bond_miimon: 100
    bond_slaves: [eth2, eth3]

host_vars/host2

interfaces_ether_interfaces:
  - device: eth0
    bootproto: static
    address: 192.168.1.150
    netmask: 255.255.255.0
    gateway: 192.168.1.1

Create a playbook which applies this role to all hosts as shown below, and run the playbook. All the servers should have their network interfaces configured and routes updated.

- hosts: all
  roles:
    - role: MichaelRigart.interfaces

Note: Ansible needs network connectivity throughout the playbook process, you may need to have a control interface that you do not modify using this method so that Ansible has a stable connection to configure the target systems.

9. CentOS 8 cloud image workaround

CentOS 8 cloud images ship with ifcfg files for ens3 and eth0. ifcfg-ens3 seems to be a relic from the image build process, and causes the network service to fail. ifcfg-eth0 is useful for most virtual machines, but if a cloud image is deployed on bare metal and eth0 is absent, the network service will fail. This role will by default remove these files, if there is no such interface on the system, and no such interface is specified in the role variables.

This workaround is configured via interfaces_workaround_centos_remove. To set a different interface file to remove:

interfaces_workaround_centos_remove:
  - eth1

Or to avoid performing this workaround:

interfaces_workaround_centos_remove: []

10. Allowed addresses

Sometimes it may be useful to not immediately assign an IP address to an interface, but to allow another process to assign one. An example use case is a virtual IP address dynamically added or by a process such as keepalived. This may be configured via an allowed_addresses field in an Ethernet, bond or bridge interface configuration.

- hosts: myhost
  roles:
    - role: MichaelRigart.interfaces
      interfaces_ether_interfaces:
        - device: eth0
          bootproto: static
          address: 0.0.0.0
          allowed_addresses:
            - 10.0.0.2

11. Custom options for static routes

Adding custom options to static routes is possible via the options attribute, which should be a list.

- hosts: myhost
  roles:
    - role: MichaelRigart.interfaces
      interfaces_ether_interfaces:
        - device: eth0
          bootproto: static
          address: 0.0.0.0
          route:
           - network: 192.168.200.0
             netmask: 255.255.255.0
             gateway: 192.168.1.1
             options:
               - onlink
               - metric 400

12. Configure an IPoIB (infiniband) interface

Configuring an IPoIB interface is possible using type: ipoib when defining the interface.

WARNING: You can configure the ip address and routes for an IPoIB interface but other functionalities like vlans are not supported in infiniband networks

- hosts: myhost
  roles:
    - role: MichaelRigart.interfaces
      interfaces_ether_interfaces:
        - device: eth0
          bootproto: static
          address: 192.168.1.150
          netmask: 255.255.255.0
          gateway: 192.168.1.1
        - device: ib0
          bootproto: static
          address: 10.10.1.10
          netmask: 255.255.255.0
          type: ipoib

13. Configure ethtool options (RedHat-family only)

Setting ethtool options on an interface is possible using the ethtool_opts attribute, which should be a string. For example, this can be used to set RX/TX ring parameters. This is only supported on distributions of the RedHat family.

- hosts: myhost
  roles:
    - role: MichaelRigart.interfaces
      interfaces_ether_interfaces:
        - device: eth0
          bootproto: static
          address: 192.168.1.150
          netmask: 255.255.255.0
          gateway: 192.168.1.1
          ethtool_opts: "-G ${DEVICE} rx 8192 tx 8192"

To apply ethtool options to bond slaves or bridge ports, set the attribute on the bond or bridge itself. Setting different options per underlying interface is not supported at this time.

14. Configure firewalld zones (RedHat-family only)

Adding interface to firewalld zone is possible using the zone attribute. This is only supported on distributions of the RedHat family.

- hosts: myhost
 roles:
   - role: MichaelRigart.interfaces
     interfaces_ether_interfaces:
       - device: eth0
         bootproto: static
         address: 192.168.1.150
         netmask: 255.255.255.0
         gateway: 192.168.1.1
         zone: trusted

15. Pause to wait for interfaces to become active

On some OS distributions (including Ubuntu), it may be necessary to wait after bouncing network interfaces before they are active. This can be done by setting interfaces_pause_time to a number of seconds to delay.

16. Configure HW(MAC) address for interface

Configuring interface HW adrress is possible using the hwaddr attribute. This alone may not be sufficient to change MAC from default one, however specifying hw address is necessary for some systems.

 - hosts: myhost
   roles:
     - role: MichaelRigart.interfaces
       interfaces_ether_interfaces:
         - device: eth0
           bootproto: static
           address: 192.168.1.150
           netmask: 255.255.255.0
           gateway: 192.168.1.1
           hwaddr: 00:11:22:33:44:55

17. Configure HW(MAC) address for bonded/bridged interface

Configuring interface HW adrress is possible using the hwaddr attribute.

- hosts: myhost
  roles:
    - role: MichaelRigart.interfaces
      interfaces_bond_interfaces:
        - device: bond0
          bootproto: dhcp
          bond_mode: 802.3ad
          hwaddr: 00:11:22:33:44:55
      interfaces_bridge_interfaces:
       -  device: br1
          type: bridge
          bootproto: dhcp
          hwaddr: 00:11:22:33:44:66
          ports: [eth1, eth2]

18. Routes and rules can be a mix of strings and hashes (a.k.a. dict, mapping, associative array, etc.) allowing the role to handle rules and routes outside the expected formats.

    The example below configures an interface, to act as a second interface so that any traffic that hits it is returned via the same interface. In addition internal traffic is marked so it can be picked up by some other service (like HAproxy).

host_vars/proxy1

interfaces_route_tables:
    - name: frontend
      id: 200
    - name: marktable
      id: 100
interfaces_ether_interfaces:
    - device: eth1
      bootproto: static
      address: 10.10.10.1
      netmask: 255.255.255.0
      defroute: false
      route:
        - table: frontend
          device: eth1
          network: 0.0.0.0
          netmask: 0.0.0.0
          gateway: 10.10.10.254
        - "local 0.0.0.0/0 dev lo table marktable"
      rules:
        - from: 10.10.10.1
          table: frontend
        - "fwmark 1 lookup marktable"

Example Playbook

- hosts: servers
  roles:
     - { role: MichaelRigart.interfaces, become: true }

License

GPLv3

Author Information

Michaël Rigart michael@netronix.be