Automated underlay network provisioning

An underlay network is a physical Layer 3 network. An overlay network is a virtual network built on top of the underlay network. The main stream overlay technology is VXLAN. For more information about VXLAN, see VXLAN Configuration Guide.

Automated underlay network provisioning sets up a Layer 3 underlay network for users. It is implemented by automatically executing configurations (such as IRF configuration and Layer 3 reachability configurations) in user-defined template files.

Provisioning prerequisites

Before you start automated underlay network provisioning, complete the following tasks:

  1. Finish the underlay network planning (such as IP address assignment, reliability design, and routing deployment) based on user requirements.

  2. Configure the DHCP server and the TFTP server.

  3. Upload startup image files to the TFTP server. Skip this step if all devices in the VCF fabric use the same startup image files and no software update is required.

  4. Create template files for all device roles based on the topology type and upload the template files to the TFTP server. A template file is a file that ends with .template file extension. The following are different template types:

    • Template for a leaf node in a VLAN.

    • Template for a leaf node in a VXLAN with a centralized IP gateway.

    • Template for a leaf node in a VXLAN with distributed IP gateways.

    • Template for a spine node in a VLAN.

    • Template for a spine node in a VXLAN with a centralized IP gateway.

    • Template for a spine node in a VXLAN with distributed IP gateways.

Process of automated underlay network provisioning

The device finishes automated underlay network provisioning as follows:

  1. Starts up with factory configuration.

  2. Obtains an IP address, the IP address of the TFTP server, and a template file name in the networktype.template format from the DHCP server.

  3. Downloads a template file (named networktype_role.template) that corresponds with its device role from the TFTP server.

  4. Parses the template file and executes the configurations in the template file.


    [NOTE: ]

    NOTE:

    • If the template file contains software version information, the device first compares the software version with the current software version. If the two versions are inconsistent, the device downloads the new software version to perform software upgrade. After restarting up, the device executes the configurations in the template file.

    • If the template file does not include IRF configurations, the device does not save the configurations after executing all configurations in the template file. To save the configurations, use the save command.


Template file

A template file contains the following contents: