OVN DB Sync Integration with neutron-ovn-db-sync-util

Overview

The OVN Octavia provider includes a synchronization plugin that integrates with Neutron’s neutron-ovn-db-sync-util CLI tool. This allows operators to synchronize both Neutron and Octavia resources with the OVN Northbound database in a single operation.

The plugin is automatically discovered when ovn-octavia-provider is installed, and is invoked as part of the standard Neutron OVN database synchronization process.

Plugin Registration

The plugin is registered via setuptools entry point:

[entry_points]
neutron.ovn.db_sync =
    octavia_ovn_sync = ovn_octavia_provider.ovn.db_sync:OctaviaOvnSynchronizer

This allows the Neutron sync utility to automatically discover and load the Octavia synchronizer when it runs.

Usage

Using with neutron-ovn-db-sync-util

To synchronize both Neutron and Octavia resources with OVN, run the neutron-ovn-db-sync-util command:

neutron-ovn-db-sync-util \
    --config-file /etc/neutron/neutron.conf \
    --config-file /etc/neutron/plugins/ml2/ml2_conf.ini \
    --ovn-neutron_sync_mode repair

Note

You do NOT need to pass /etc/octavia/octavia.conf as a config file. The Octavia plugin automatically loads it from the standard location (/etc/octavia/octavia.conf). Passing it would cause conflicts with Neutron’s database connection configuration.

This will:

1. Synchronize Neutron resources (networks, ports, routers, etc.)

2. Synchronize Octavia load balancers (OVN provider only)

3. Use the same OVN Northbound database connection

4. Apply the same sync mode to all resources

Sync Modes

The Octavia OVN synchronizer supports the following modes:

repair (Recommended)

Synchronizes all Octavia load balancers with the OVN provider with the OVN Northbound database. This is the default and recommended mode.

Example:

neutron-ovn-db-sync-util \
    --config-file /etc/neutron/neutron.conf \
    --config-file /etc/neutron/plugins/ml2/ml2_conf.ini \
    --ovn-neutron_sync_mode repair

log (Not Supported)

The Octavia synchronizer does not support read-only verification mode. If you run the sync utility in log mode, the Octavia plugin will skip synchronization and log a warning.

migrate

In migrate mode (used for OVS to OVN migration), the Octavia synchronizer behaves the same as in repair mode, synchronizing all load balancers.

Synchronizing Only Octavia Resources

If you only need to synchronize Octavia load balancers without Neutron resources, you can use either approach:

Option 1: Using the plugin (Recommended)

neutron-ovn-db-sync-util \
    --config-file /etc/neutron/neutron.conf \
    --config-file /etc/neutron/plugins/ml2/ml2_conf.ini \
    --sync_plugin octavia_ovn_sync \
    --ovn-neutron_sync_mode repair

This will synchronize only Octavia load balancers, skipping Neutron resources.

Option 2: Using the standalone tool

octavia-ovn-db-sync-util

The standalone tool remains available for compatibility and can be used if you prefer a dedicated command for Octavia synchronization.

Recommended Workflows

Synchronize everything (Neutron + Octavia):

# Stop services first
sudo systemctl stop neutron-server octavia-api

# Run sync
neutron-ovn-db-sync-util \
    --config-file /etc/neutron/neutron.conf \
    --config-file /etc/neutron/plugins/ml2/ml2_conf.ini \
    --ovn-neutron_sync_mode repair

# Restart services
sudo systemctl start neutron-server octavia-api

Synchronize only Octavia:

# Stop Octavia services first
sudo systemctl stop octavia-api

# Run Octavia sync (using plugin)
neutron-ovn-db-sync-util \
    --config-file /etc/neutron/neutron.conf \
    --config-file /etc/neutron/plugins/ml2/ml2_conf.ini \
    --sync_plugin octavia_ovn_sync \
    --ovn-neutron_sync_mode repair

# Or use standalone tool
# octavia-ovn-db-sync-util

# Restart Octavia
sudo systemctl start octavia-api

Configuration

Required Configuration Files

Configuration passed to neutron-ovn-db-sync-util:

• /etc/neutron/neutron.conf - Core Neutron configuration

• /etc/neutron/plugins/ml2/ml2_conf.ini - ML2 plugin configuration (includes OVN connection settings)

Configuration automatically loaded by the plugin:

• /etc/octavia/octavia.conf - Octavia configuration (includes Octavia database connection and OVN provider settings)

The Octavia plugin automatically searches for and loads octavia.conf from standard locations (/etc/octavia/octavia.conf, ~/octavia.conf, ./octavia.conf). You should NOT pass it via --config-file to avoid database connection conflicts.

OVN Connection Sharing

The Octavia synchronizer reuses the OVN Northbound database connection established by Neutron. This means:

• Only the OVN connection settings in the Neutron ML2 configuration are used

• No separate OVN connection is created for Octavia synchronization

• Reduced overhead and consistent connection parameters

Limitations

The Octavia OVN synchronizer has the following limitations:

1. No LOG Mode: The plugin does not support read-only verification. When run in LOG mode, the plugin skips synchronization and logs a warning.

2. OVN Provider Only: Only load balancers using the OVN provider are synchronized. Load balancers using other providers (e.g., Amphora) are not affected.

3. Octavia Configuration Location: The plugin expects Octavia configuration at /etc/octavia/octavia.conf or other standard locations. It cannot be passed via --config-file to avoid database connection conflicts.

Best Practices

Pre-Sync Checklist

Before running the synchronization utility:

1. Stop Services: Stop neutron-server and octavia-api to prevent race conditions

2. Backup Databases: Create backups of both Neutron and Octavia databases

3. Verify OVN Connection: Ensure OVN NB database is accessible

Post-Sync Verification

After synchronization completes:

1. Check Logs: Review output for errors or warnings

2. Verify Resources: Confirm load balancers match between Octavia and OVN

3. Restart Services: Bring services back online