[Failover]

[Simon Hobson]

Cedric OLLIVIER wrote:
> I would like a local server to manage the dhcp requests even if the remote peer has not been reachable yet (no sync was done before).
> It is possible that one server operates alone without its peer if it is configured as follows:
>
>
>   failover peer "dhcp-failover" state {
>   my state partner-down;
> }

> Primary can manage the adress pool without any previous synchronisation (state "partner-down").

The whole point of failover is that the two servers *MUST* communicate their offerings to each other as they happen. Ie, when an address is leased to a client, **BOTH** servers must know about that lease. Without that knowledge, there is no way for a secondary server to take over as it will have no means of a) offering a client the same address it already has, or more importantly b) not offering an address to a client when that address has been leased to another client.
So the only way to maintain a failover pair AS A FAILOVER PAIR is for them to be active at the same time and communicating changes to each other.
Now there are techniques to arrange that one of the pair is the primary and the secondary one doesn't do much. But what you do, both need to know what leases are issued and to which clients.