Open vSwitch VLAN Bridge Setup

This repository contains scripts and configuration files to set up an Open vSwitch (OVS) bridge for a host with VLAN trunking and access ports.

Topology

• ens4 and ens6: Trunk ports carrying VLANs 2201–2205

• ens5: Access port on VLAN 2201, used for management (IP: 10.10.3.2/24)

• The diagram:

Files

• setup-ovs.sh: Configures the OVS bridge and ports
• setup-ovs.service: systemd unit to automatically apply the OVS setup on boot
• netplan/01-netcfg.yaml: Netplan config to assign an IP address on VLAN 2201

⚠️ Important

Note: The IP addresses, VLAN IDs, and interface names in the YAML and setup script are specific to one environment.

You must update these values to match your network infrastructure:

• IP address (10.0.22.3/24) → your desired management IP on the ens3 port (in netplan)
• VLANs (2201–2205) → your VLAN range
• Interfaces (ens4, ens5, ens6) → your actual NIC names

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Installation Instructions

1. Install Open vSwitch

sudo apt update
sudo apt install -y openvswitch-switch openvswitch-common

2. Copy Setup Script

sudo cp setup-ovs.sh /usr/local/bin/
sudo chmod +x /usr/local/bin/setup-ovs.sh

3. Install systemd Service

sudo cp setup-ovs.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable setup-ovs.service

4. Configure Netplan

Edit /etc/netplan/01-netcfg.yaml to include a defined br0 bridge:

network:
  version: 2
  renderer: networkd

#this configuration is for the OOB (Out-Of-Band) management of the host only.

  ethernets:
    ens3: #change this to you out-of-band management port
      dhcp4: false
      dhcp6: false
      addresses:
      - 10.0.22.3/24 #change this to the IP you want to assign
      routes:
      - to: default
        via: 10.0.22.254 #change this to the gateway of interface
      nameservers:
        addresses: [8.8.8.8] #change to whatever the DNS you want to use

Then apply the configuration:

sudo netplan generate
sudo netplan apply

5. Reboot the Host

sudo reboot

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Validation Steps

After rebooting:

1. Check if bridge br0 is are up:

   ip addr show br0
   

2. Test IP connectivity:

   ping 10.0.22.3

3. Test SSH access to 10.0.22.3 from another host.

4. Check Open vSwitch config:

   sudo ovs-vsctl show

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Troubleshooting

Network Startup Delay

If the system stalls at systemd-networkd-wait-online.service, disable and mask it:

sudo systemctl disable systemd-networkd-wait-online.service
sudo systemctl mask systemd-networkd-wait-online.service

Interface br0 Not Defined

Ensure that br0 is declared in the Netplan YAML. Netplan must define the bridge, even if Open vSwitch also creates it.

OVS Bridge Already Exists

If ovs-vsctl shows: could not add network device br0 to ofproto (file exists), the bridge might have been defined both by Netplan and OVS. To avoid this:

• Use Netplan only to define the existence of br0 (with no interfaces).
• Let setup-ovs.sh handle the OVS configuration.

Still Delays on Boot?

Create a systemd-networkd override for br0:

sudo mkdir -p /etc/systemd/network/
cat <<EOF | sudo tee /etc/systemd/network/br0.network
[Match]
Name=br0

[Network]
DHCP=no

[Link]
RequiredForOnline=no
EOF

sudo systemctl restart systemd-networkd

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Requirements

• Ubuntu system with Open vSwitch installed
• systemd-networkd as the Netplan renderer

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License

MIT License