Why does dhcpd node in failover setup delete DNS records following daemon restart?
Issue
Two systems are running dhcpd in failover mode using dynamic DNS. If one of them goes down unexpectedly then upon dhcpd service restart some DNS records with valid leases may get deleted. The exact scenario is as follows:
- Both nodes (A and B) are up and serving dhcp leases.
- Node A serves lease for host MYHOST.mydomain.com and updates DNS record.
- Node A crashes.
- Host MYHOST.mydomain.com renews its lease, node B serves it.
- The original lease served in step 2 expires but the one served in step 4 doesn't.
- Node A is brought back up and dhcpd is restarted.
- DNS records for MYHST.mydomain.com are removed despite the fact the lease obtained in step 4 is still valid.
Environment
Red Hat Enterprise Linux 7
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