Automatic failover and health checks for Cloudflare® sites

Round-robin DNS + failover

Round-robin DNS is an easy to implement technique to distribute traffic and load between servers.

To protect a round-robin setup against failure, we included another check mode: “automatic failover (remove DNS record)”.

If the primary server of the check fails, the DNS entry will be removed from the pool.

Technically this is done by changing the domain name of the DNS entry to a defined value (a prefix is added, i.e. and changing it back, once the check is “ok” again.

To set up Round-robin DNS + failover:

  • add multiple DNS entries for your domain in Cloudflare DNS page
  • use the ‘update from cloudflare’ button in dashboard
  • create a check for each DNS entry with:
    • your domain selected
    • only the primary server selected (the same one as in the DNS entry!)
    • click “Save & Check”
    • if ok: change the check mode to ‘automatic failover (remove DNS record)’ and save

To test the DNS entry removal, use the ‘Test remove’ button in checks page. Do not forget to use the ‘Test restore’ button to restore the entry to previous name.

Note: Please do not modify the DNS entries in Cloudflare, if there are checks active for that entry - or there will be strange results ;)

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