Sometimes (about 5 times this month), I have the following errors in the haproxy logs and I don’t really understand why:
Server XXXXX is going DOWN for maintenance (DNS timeout status). 0 active and 0 backup servers left. 0 sessions active, 0 requeued, 0 remaining in queue.
Server XXXXX administratively READY thanks to valid DNS answer.
Server XXXXX ('XXXXXXX') is UP/READY (resolves again).
The HA Proxy version is 1.7.9 and I use the nbproc parameter in the configuration.
I know there is a bug about this parameter and the DNS resolution (DNS Resolution *Sigh* v1.7.1) but it seems to be resolved in the 1.7.3 (https://www.haproxy.org/download/1.7/src/CHANGELOG).
The HA Proxy servers use AWS DNS to resolve the backend name.
Thanks for your help,