The command snippet for GKE cluster creation as specified in a3/README.md is missing user's own credential mount (which is correctly done in the main readme for MIG example).
It's also missing working GKE version specification.
NCCL benchmark example as well as LIT GPT fail with cryptic errors until I mentioned the GKE version = "1.27.8-gke.1067000"
(Thanks to the recommendation from @samuelkarp.