DHCP failover maintains redundancy between two DHCP servers, enabling seamless service takeover in case of unavailability, and minimizing downtime and disruption to network operations.
Failover relationships for Kea DHCP servers in Micetro are exclusively managed at the server level. When two Kea DHCP servers are in a failover relationship, Micetro ensures the identical replication of DHCP-related data from the primary to the secondary server. The synchronization process continues, copying changes from the primary to the secondary server, until the failover relationship is deleted. This means that all scopes, pools, reservations, etc., are meticulously mirrored between the two servers, all under the exclusive management of Micetro.
Key aspects of Kea DHCP failover include:
- Failover relationships: Establish, create, and remove failover relationships—one per service type—forming a redundant and synchronized configuration. These relationships are crucial for maintaining a synchronized state between DHCP servers. This feature is particularly beneficial in ensuring High Availability and fault tolerance for DHCP services.
- Server-level management: Failover relationships are managed at the server level, seamlessly integrating with Micetro. Micetro's failover management is built on top of the High Availability feature of Kea DHCP servers.
- Integration with Micetro: Micetro provides streamlined DHCP service management across the network, offering a comprehensive approach to failover relationships and scopes.
Two modes of failover operation are supported:
- Load balancing
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- Designate one server as primary and another as secondary.
- During normal operation, the two servers are identical.
- When the two servers are started at (nearly) the same time and synchronize their lease databases, the primary server always synchronizes its database first. The secondary waits for the primary to finish before it starts its own synchronization.
- Hot standby
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- Designate one server as primary and another as secondary.
- During normal operation, only the primary server responds to DHCP requests.
- The secondary (or standby) server receives lease updates from the primary server over the control channel.
- When the secondary server perceives the primary to be offline, it begins responding to DHCP queries.
Refer to the following topics for instructions on managing Kea DHCP failover relationships in Micetro: