Question

A financial services company runs a stateful TCP application behind an internal passthrough Network Load Balancer in a single region. The application stores per-client session state in memory on each backend VM, so all packets from a given client must consistently reach the same backend instance for the life of the session. Clients connect from within the same VPC. Which load balancer configuration should the network engineer apply to meet this requirement?

Accepted Answer

Set the backend service session affinity to CLIENT_IP (or a more specific tuple such as CLIENT_IP_PORT_PROTO) so connections from the same client hash to the same backend.

Answer

Enable Cloud CDN on the backend service to cache client sessions closer to the backends.

Answer

Switch to an internal Application Load Balancer and enable generated-cookie (HTTP cookie) session affinity.

Answer

Configure connection draining with a 300-second timeout and leave session affinity set to NONE.