CORD will require various interfaces bonded then bridged, when used with VTN.
This playbook creates interfaces in the following topology for both fabric and management networks. The example below is for the fabric interfaces - replace fabric with management for all variable names for that interface:
A bond interface is defined, named fabricbond, which contains physical interfaces connected to the switching fabric.
A fabricbridge is defined, which contains:
The bridge is assigned an IP address, specified by fabric_net_ip_cidr, which is an IP address in CIDR format (ex: 10.234.56.7/8) which is used to create the IP address of the interface, it's network mask, broadcast address, and so on. The ipcalc tool can be useful for calculating these values.
The interface configuration files are stored in /etc/network/interfaces.d/management.cfg and /etc/network/interfaces.d/fabric.cfg.
Once these files are created, the interfaces they describe are brought up using ifup, and should be recreated if the system reboots.
An example ansible inventory is given in example-inventory.yaml, and uses the YAML inventory format
For this playbook to function, you must define one or both of the the fabric_net_ip_cidr or management_net_ip_cidr variables as described above for each host. If you don't define one of these variables, the corresponding bridge or bond will not be created.
ansible-playbook -i <inventory_file> prep-interfaces-playbook.yaml
There are three ways to select which interfaces are added to each bond. You may use these additively in any combination - they'll simply add more interfaces to the bond.
The three methods are:
By interface name: Specific interface names can be listed for each bond. This is useful if you have a specific configuration and know the names of interfaces before you configure the system, or if you have multiple of the same manufacturer of NIC. This is used by adding interface names (as listed in ansible_intefaces when running the setup task) to the (fabric|management)_net_interfaces list.
By kernel module name: By creating a list of kernel module names for the bond device, interfaces can be selected. For example, every interface using the em or mlx4 driver might be in the fabric bond. The specific driver names can be found by running ansible's setup module on a host, and looking through the output. For example, if you have an interface on the system named eth0, the driver name would befound in ansible_eth0.module. This is used by adding kernel module names to the (fabric|management)_net_kmods list.
By hardware (MAC) address: The MAC addresses of the interfaces can be listed. This can be useful in systems where the intefaces change names through kernel or driver updates. This is used by adding 48-bit hardware addresses in the lowercase, zero padded, colon delimited hex format (01:23:45:67:89:ab) to the (fabric|management)_net_hwaddrs list.
These variables are optional, and set on a per-host basis. Not setting them will result in an empty bond in a bridge.