Using a Deployed OVB Environment

After an OVB environment has been deployed, there are a few things to know.

  1. The undercloud vm can be used with something like TripleO to do a baremetal-style deployment to the virtual baremetal instances deployed previously.

  2. To reset the environment, usually it is sufficient to do a nova rebuild on the undercloud to return it to the original image. To ensure that no traces of the old environment remain, the baremetal vms can be rebuilt to the ipxe-boot image as well.


    If you are relying on the ipxe-boot image to provide PXE boot support in your cloud because Nova does not know how to PXE boot natively, the baremetal instances must always be rebuilt before subsequent deployments.


    Do not rebuild the bmc. It is unnecessary and not guaranteed to work.

  3. If the host cloud’s tenant network MTU is 1500 or less, it will be necessary to configure the deployed interfaces with a smaller MTU. The tenant network MTU minus 50 is usually a safe value. For the undercloud this can be done by setting local_mtu in undercloud.conf.


    In Mitaka and older versions of TripleO it will be necessary to do the MTU configuration manually. That can be done with the following commands (as root):

    # Replace 'eth1' with the actual device to be used for the
    # provisioning network
    ip link set eth1 mtu 1350
    echo -e "\ndhcp-option-force=26,1350" >> /etc/dnsmasq-ironic.conf
    systemctl restart 'neutron-*'
  4. If using the full network isolation provided by one of the all-networks*.yaml environments then a TripleO overcloud can be deployed in the OVB environment by using the network templates in the overcloud-templates directory. The names are fairly descriptive, but this is a brief explanation of each:

    • network-templates: IPv4 multi-nic. Usable with the network layout deployed by the all-networks.yaml environment.
    • ipv6-network-templates: IPv6 multi-nic. Usable with the network layout deployed by the all-networks.yaml environment.
    • bond-network-templates: IPv4 multi-nic, with duplicate public interfaces for testing bonded nics. Usable with the network layout deployed by the all-networks-public-bond.yaml environment.

    The undercloud’s public interface should be configured with the address of the default route from the templates in use. Firewall rules for forwarding the traffic from that interface should also be added. The following commands will make the necessary configuration:

    cat >> /tmp/eth2.cfg <<EOF_CAT
      - type: interface
        name: eth2
        use_dhcp: false
          - ip_netmask:
          - ip_netmask: 2001:db8:fd00:1000::1/64
    sudo os-net-config -c /tmp/eth2.cfg -v
    sudo iptables -A POSTROUTING -s ! -d -j MASQUERADE -t nat