After a lot of trials I’ve found this document
https://cloud.google.com/kubernetes-engine/docs/how-to/ingress-features#cloud_cdn where is specified that Multi Cluster Ingress (used by Anthos) does not allows setting of some cache parameters needed by Google Load Balancer CDN, in particular cacheMode / defaultTtl / serveWhileStale. The default and immutable cache TTL of 1 hour applied to arbitrary selected static content is too small to pass performances quality score. This way MCI is unusable for production high-performances web site. We already tried to move all static assets to a dedicated sub-domain served by a standard GLB, but still have problems with many html pages that need cache time > 1 hour to avoid continue hits against backend. Any suggestion or workaround is appreciated.