# Deploying with Custom Networks¶

TripleO offers the option of deploying with a user-defined list of networks, where each network can be enabled (or not) for each role (group of servers) in the deployment.

## Default networks¶

TripleO offers a default network topology when deploying with network isolation enabled, and this is reflected in the network_data.yaml file in tripleo-heat-templates.

These default networks are as follows:

• External - External network traffic (disabled by default for Compute/Storage nodes)
• InternalApi - Internal API traffic, most intra-service traffic uses this network by default
• Storage - Storage traffic
• StorageMgmt - Storage management traffic (such as replication traffic between storage nodes)
• Tenant - Tenant networks for compute workloads running on the cloud

## Deploying with custom networks¶

Each network is defined in the network_data.yaml file. There is a sample file in /usr/share/openstack-tripleo-heat-templates, or the tripleo-heat-templates git repository which can be copied and modified as needed.

The network_data.yaml file contains a list of networks, with definitions like:

- name: CustomNetwork
vip: false
name_lower: custom_network
ip_subnet: '172.16.6.0/24'
allocation_pools: [{'start': '172.16.6.4', 'end': '172.16.6.250'}]
gateway_ip: '172.16.6.1'


The data in network_data.yaml is used to perform templating with jinja2 such that arbitrary user-defined networks may be added, and the default networks may be modified or removed.

The steps to define your custom networks are:

1. Copy the default network_data.yaml provided by tripleo-heat-templates:

cp /usr/share/openstack-tripleo-heat-templates/network_data.yaml custom_network_data.yaml

2. Modify the custom_network_data.yaml file as required. The network data is a list of networks, where each network contains at least the following items:

name

Name of the network (mandatory)

vip

Enable creation of a virtual IP on this network

ip_subnet

IP/CIDR, e.g. '10.0.0.0/24'

allocation_pools

IP range list, e.g. [{'start':'10.0.0.4', 'end':'10.0.0.250'}]

gateway_ip

gateway for the network

vlan (supported in Queens and later)

Vlan ID for this network.

Other options are supported, see the documentation in the default network_data.yaml for details.

Warning

Currently there is no validation of the network subnet and allocation_pools, so care must be take to ensure these are consistent, and do not conflict with any existing networks, otherwise your deployment may fail or result in unexpected results.

3. Copy network configuration templates, add new networks.

Prior to Queens the nic config templates are not dynamically generated, so it is necessary to copy those that are in use, and add parameters for any additional networks, for example:

cp -r /usr/share/openstack-tripleo-heat-templates/network/config/single-nic-vlans custom-single-nic-vlans


Each file in single-nic-vlans will require update to add parameters for each custom network. Copy those that exist for the default networks, and rename to match the name field in custom_network_data.yaml.

Note

In Queens and later the NIC config templates are dynamically generated so this step is only necessary when creating custom NIC config templates, not when just adding a custom network.

It is necessary to adjust the environment paths to match the location of the copied nic templates above:

cp /usr/share/openstack-tripleo-heat-templates//environments/net-single-nic-with-vlans.yaml custom-net-single-nic-with-vlans.yaml


Edit the paths for each role to reference custom-single-nic-vlans directory created above.

2. To deploy you pass the custom_network_data.yaml file via the -n option to the overcloud deploy, for example:

openstack overcloud deploy --templates -n custom_network_data.yaml -e custom-net-single-nic-with-vlans.yaml


Note

It is also possible to copy the entire tripleo-heat-templates tree, and modify the network_data.yaml file in place, then deploy via --templates <copy of tht>.