DevOpsil
Intermediateload-balancing

The Phantom 504s

Users are intermittently getting 504 Gateway Timeout errors — but only about 10% of requests. The backend appears healthy and responds quickly when you test it directly. The load balancer health checks pass. A deeper investigation reveals the LB is routing traffic to a node that's technically 'healthy' but has a saturated connection table.

Aareez Asif
Aareez Asifguides you
4 steps60s per step400 max points
INCOMING INCIDENT
$ incident --describe the-phantom-504s
Users are intermittently getting 504 Gateway Timeout errors — but only about 10% of requests. The backend appears healthy and responds quickly when you test it directly. The load balancer health checks pass. A deeper investigation reveals the LB is routing traffic to a node that's technically 'healthy' but has a saturated connection table.
4
Decision Points
60s
Per Step
400
Max Score
200
Passing Score