Failover

HAProxy has failover!

backend mybackend server s1 10.0.0.101:80 check server s2 10.0.0.102:80 check server s3 10.0.0.103:80 check backup server s4 10.0.0.104:80 check backup

In the above config s1 and s2 are the primary servers. They have the check keyword turned on which turns on healthchecking. If both fail then s3 is pulled into rotation. If s3 fails then it will pull s4 into rotation. Finally, if s4 fails it will return a http status code 503 SERVICE UNAVAILABLE.

Reference

• HAProxy Failover