4.2. Networking

It is important to plan what networking type to use and the subnets in your environment so that you can properly map services and hosts to correctly communicate with each other.
The installer providers two different networking options:
Nova
This is the legacy networking type where the Compute nodes manage IP forwarding, bridges, and VLANs.
Neutron
This is the newer networking service that operates autonomously and manages software-based networks, static and floating IP addresses, and DHCP. The installer maps and deploys this service onto each Controller node in a RHEL OpenStack Plaform environment.
The installer also provides functions to map different services to different subnets. For example, the hosts in Figure 4.1, “Sample Deployment Topology” communicate with each other and with external networks over the four following subnets:
  • The green subnet represents the provisioning network that the installer uses for provisioning and configuring hosts. This network carries traffic between the installer and the hosts in the deployment. This is the network that the installer uses to boot hosts using PXE, and to set up and configure hosts when you provision a RHEL OpenStack Platform environment. While this network traffic type is carried over a dedicated subnet in this deployment, this network traffic type can be shared with any of the network traffic types carried by the blue network outlined below. The subnet that carries this network traffic type must be assigned to every host in the deployment.
  • The dark blue subnet represents a private network that carries network traffic between the nodes in a RHEL OpenStack Platform environment. This network carries management, cluster management, administrative API, storage, and storage clustering network traffic. The subnet that carries these network traffic types must be assigned to every host in the deployment.
  • The light blue subnet represents a public network that carries network traffic between instances in the RHEL OpenStack Platform environment and external networks. This network provides external network connectivity to virtual machines. A dedicated subnet must be created to carry this type of network traffic. The subnet that carries this network traffic type is only assigned to controller nodes.
    This network also allows the installer to communicate with external network resources such as the Content Delivery Network. It is configured manually on the machine hosting the installer. See Section 3.5, “Configuring a Gateway” for more information.
All scenarios in this guide require three networks:
  • A network for the installer's provisioning network
  • A network for OpenStack services
  • A network for external access
The initial configuration of the installer already contains a subnet entry for the provisioning network (10.1.1.0/24). Thie following procedures show how to map networks for an External subnet (192.168.1.0/24) and OpenStack services (10.1.1.0/24).

Important

An incompatibility between Modular Layer 2 Population and Layer 3 High Availability plugins means only one network configuration plugin should be used. The installer automatically configures Layer 3 High Availability (l3_ha) for use if Layer 2 Population (l2_population) is disabled. Likewise, if Layer 2 Population is enabled, the Layer 3 High Availability is disabled.

4.2.1. Creating an External Subnet

The following procedure maps the external network (192.168.1.0/24) for provisioned hosts to use.

Procedure 4.1. Creating an External Subnet

  1. From the title bar in the main screen of the user interface, click InfrastructureSubnets.
  2. Click New Subnet.
  3. Configure general subnet details:
    1. Enter a name for the subnet (e.g. External) in the Name field.
    2. Enter the network address of the subnet (e.g. 192.168.1.0) in the Network address field.
    3. Enter the network mask for the subnet (e.g. 255.255.255.0) in the Network mask field.
    4. Enter the address of a gateway (e.g. 192.168.1.1) in the Gateway address field.
    5. Enter the address of the primary DNS server, if any, in the Primary DNS server field.
    6. Enter the address of the secondary DNS server, if any, in the Secondary DNS server field.
    7. Select None as IP address management source from the IPAM list. This lets the external networks' DHCP server take care of the IP management.
    8. Optionally, enter the ID of a VLAN for the subnet.
    9. Select DHCP as the default boot mode for interfaces assigned to the subnet from the Boot mode list.
  4. Configure domain membership:
    1. Click Domains.
    2. Check all domains for which the subnet is a member.

      Note

      This is an optional step and if you need to add the domain for your external network, you can do so later by navigating to InfrastructureDomains.
  5. Click the Capsules tab to view the capsule settings. A capsule acts as a proxy for certain installer services, such as DHCP, TFTP, and DNS.
    The capsule settings are only required for the default provisioning subnet. This is because the installer uses this subnet for host provisioning and deployment of Red Hat OpenStack Platform services. Any new subnets added to the installer do not require capsule settings.
  6. Click Submit.
You now have an external subnet mapping to use in your RHEL OpenStack Platform environment.

4.2.2. Creating an OpenStack Services Subnet

The following procedure maps the OpenStack services network (10.1.2.0/24) for provisioned hosts to use.

Procedure 4.2. Creating an OpenStack Services Subnet

  1. From the title bar in the main screen of the user interface, click InfrastructureSubnets.
  2. Click New Subnet.
  3. Configure general subnet details:
    1. Enter a name for the subnet (e.g. OpenStack Services) in the Name field.
    2. Enter the network address of the subnet (e.g. 10.1.2.0) in the Network address field.
    3. Enter the network mask for the subnet (e.g. 255.255.255.0) in the Network mask field.
    4. Enter the address of a gateway (e.g. 10.1.2.1) in the Gateway address field.
    5. Enter the address of the primary DNS server, if any, in the Primary DNS server field.
    6. Enter the address of the secondary DNS server, if any, in the Secondary DNS server field.
    7. Select Internal DB as IP address management source from the IPAM list. The installer automatically assigns IP addresses to hosts.
    8. Select the default boot mode for interfaces assigned to the subnet from the Boot mode list. This sets the boot protocol for client network interfaces. Select Static to manually assign IP address through the installer's IPAM Internal Database option.
  4. Configure domain membership:
    1. Click the Domains tab.
    2. Check all domains for which the subnet is a member.

      Note

      This is an optional step and if you need to add the domain for your external network, you can do so later by navigating to InfrastructureDomains.
  5. Click the Capsules tab to view the capsule settings. A capsule acts as a proxy for certain installer services, such as DHCP, TFTP, and DNS.
    The capsule settings are only required for the default provisioning subnet. This is because the installer uses this subnet for host provisioning and deployment of Red Hat OpenStack Platform services. Any new subnets added to the installer do not require capsule settings.
  6. Click Submit.
You now have a OpenStack services subnet mapping to use in your RHEL OpenStack Platform environment.