diff --git a/sandwich-contexts-kubernetes/lib/Test/Sandwich/Contexts/Kubernetes/PostgresServer.hs b/sandwich-contexts-kubernetes/lib/Test/Sandwich/Contexts/Kubernetes/PostgresServer.hs
index 1ea109ce..4e0def79 100644
--- a/sandwich-contexts-kubernetes/lib/Test/Sandwich/Contexts/Kubernetes/PostgresServer.hs
+++ b/sandwich-contexts-kubernetes/lib/Test/Sandwich/Contexts/Kubernetes/PostgresServer.hs
@@ -205,6 +205,10 @@ postgresYaml name namespace image username password database extraEnv = [__i|
         exec:
           command:
           - pg_isready
+          \# Without -h this checks the Unix socket, which initdb's temporary
+          \# server answers before 5432 is open.
+          - -h
+          - 127.0.0.1
           - -U
           - "#{username}"
         initialDelaySeconds: 5