HOWTO: Validate DNS Cutover During a DR Failover¶

Purpose: Execute and validate DNS cutover during a DR failover, measuring propagation and confirming application reconnection with structured run records.

Difficulty: Intermediate

Track: Disaster Recovery Automation

Overview¶

DNS cutover is not an instantaneous operation: it is a sequence with timing constraints, observable propagation behaviour, and application-level effects that must all be confirmed. This HOWTO teaches the complete cutover validation workflow used in every HybridOps DR drill.

1. Pre-Cutover Preparation¶

Confirming the TTL on the target record is sufficiently low.
Pre-staging the DR target IP in DNS (where possible).
Resolver path inventory: which resolvers does the application use?

2. Executing the Record Update¶

PowerDNS API record update command.
Confirming the update is accepted by the authoritative nameserver.
Timestamp capture for the propagation window start.

3. Measuring Propagation¶

Querying each resolver path with dig.
Expected propagation timeline based on TTL.
Handling resolvers with extended caching behaviour.

4. Application Reconnection Verification¶

Connection pool drain and reconnect cycle.
Probe: successful connection to the DR target endpoint.
Error rate check: confirming no application-visible errors persist after propagation.

5. Run-record capture¶

Full cutover timeline: update timestamp, propagation observations, reconnection time.
Storing under <runtime-root>/logs/dr/dns-cutover/.
Linking to the DR drill run record as a required supporting record.

References¶

License: MIT-0 for code, CC-BY-4.0 for documentation unless otherwise stated.