Distributed Dossier Database

In a distributed architecture, it is often necessary to have the dossier database distributed among several hosts.

In the current implementation, the dossier database is available for editing only on the principal server known as master. It is in sync with several additional FindFace Security instances that serve as slaves. On the slaves, the dossier database is available only for reading and monitoring.

Important

You will be able to delete dossiers on the slaves if the master is unavailable.

Important

If a watch list on the future slave already contains dossiers, they will be replaced with those from the master during the first synchronization. All information in the previous dossiers will be lost.

Warning

Neural networks on the master and slaves must be identical.

In this section:

Configure Master/Slave Synchronization

To configure master/slave synchronization, do the following:

1. On the master, open the findface-security configuration file. Come up with a synchronization token and specify it in the SYNC_TOKEN parameter (be sure to uncomment it prior).

   sudo vi /etc/findface-security/config.py
   
   ...
   
   # ========== DossierLists sync ===========
   ...
   # token must be identical on master and slave
   # use pwgen -s 64 1
   SYNC_TOKEN = 'ABC_123456789'
   ...
   

2. Copy the synchronization token into the findface-security configuration file on the slave(s).

3. Make sure that the EXTERNAL_ADDRESS parameter of the findface-security configuration file on the slave(s) contains the same address as on the master.

The master/slave sync is now set and will be enabled once you configure a watch list replication from the master to slave(s).

Replicate Watch List from Master to Slaves

To replicate a watch list from the master to slave instances, send a POST request to the slave with the following parameters in the body:

• remote_dossier_list: id of the original watch list on the master
• remote_url: master URL
• slave_dossier_list: id of the watch list on the slave, which is to be a replica of the original watch list

POST /sync/dossier-lists/
{remote_dossier_list: 1,
remote_url: "http://172.17.46.14",
slave_dossier_list: 3}

Set Synchronization Time

By default, replicated watch lists on the slaves and the master are synced nightly at 3 a.m. You can modify the synchronization time as follows:

1. Open the findface-security configuration file on the master.

   sudo vi /etc/findface-security/config.py
   

2. Uncomment the following lines and set your own schedule.

   ...
   
   # ========== DossierLists sync ===========
   ...
   SYNC_TIME = {
       # 24 hour format
       'hour': 3,
       'minute': 0,
   }
   

Cancel Watch List Replication and Synchronization

To cancel a watch list replication and synchronization, send the following API request to the slave with the {id} of the watch list on the slave:

DELETE /sync/dossier-lists/{id}/

Duplicate Functionality to Web Interface

By default, you can enable and disable watch list replication only via API. To make the functionality available in the web interface as well, do the following:

1. Open the findface-security configuration file on the master.

   sudo vi /etc/findface-security/config.py
   

2. Enable the ffsecurity_sync plugin by uncommenting the line INSTALLED_APPS.append('ffsecurity_sync') into the plugins section:

   ...
   
   # ========== DossierLists sync ===========
   INSTALLED_APPS.append('ffsecurity_sync')
   ...
   

3. Do the same on each slave.

4. On each host, migrate the main database architecture from FindFace Security to PostgreSQL. Re-create user groups in the main database. Restart the findface-security service.

   sudo findface-security migrate
   sudo findface-security create_groups
   sudo systemctl restart findface-security.service