Config Sync

Configuration synchronization (config sync) is a feature of VyOS that permits synchronization of the configuration of one VyOS router to another in a network.

The main benefit to configuration synchronization is that it eliminates having to manually replicate configuration changes made on the primary router to the secondary (replica) router.

The writing of the configuration to the secondary router is performed through the VyOS HTTP API. The user can specify which portion(s) of the configuration will be synchronized and the mode to use - whether to replace or add.

To prevent issues with divergent configurations between the pair of routers, synchronization is strictly unidirectional from primary to replica. Both routers should be online and run the same version of VyOS.


set service config-sync secondary <address|key|timeout|port>

Specify the address, API key, timeout and port of the secondary router. You need to enable and configure the HTTP API service on the secondary router for config sync to operate.

set service config-sync section <section>

Specify the section of the configuration to synchronize. If more than one section is to be synchronized, repeat the command to add additional sections as required.

set service config-sync mode <load|set>

Two options are available for mode: either load and replace or set the configuration section.

Supported options for <section> include:
    interfaces <interface>
    protocols <protocol>
    qos <interface|policy>
    service <service>
    system <conntrack|


  • Synchronize the time-zone and OSPF configuration from Router A to Router B

  • The address of Router B is and the port used is 8443

Configure the HTTP API service on Router B

set service https listen-address ''
set service https port '8443'
set service https api keys id KID key 'foo'

Configure the config-sync service on Router A

set service config-sync mode 'load'
set service config-sync secondary address ''
set service config-sync secondary port '8443'
set service config-sync secondary key 'foo'
set service config-sync section protocols 'ospf'
set service config-sync section system 'time-zone'

Make config-sync relevant changes to Router A’s configuration

vyos@vyos-A# set system time-zone 'America/Los_Angeles'
vyos@vyos-A# commit
INFO:vyos_config_sync:Config synchronization: Mode=load,
vyos@vyos-A# save

vyos@vyos-A# set protocols ospf area 0 network ''
vyos@vyos-A# commit
INFO:vyos_config_sync:Config synchronization: Mode=load,
yos@vyos-A# save

Verify configuration changes have been replicated to Router B

vyos@vyos-B:~$ show configuration commands | match time-zone
set system time-zone 'America/Los_Angeles'

vyos@vyos-B:~$ show configuration commands | match ospf
set protocols ospf area 0 network ''

Known issues

Configuration resynchronization. With the current implementation of service config-sync, the secondary node must be online.