clusterIDVar      = env.Register("ISTIO_META_CLUSTER_ID", "", "")
	// Provider for XDS auth, e.g., gcp. By default, it is empty, meaning no auth provider.
	xdsAuthProvider = env.Register("XDS_AUTH_PROVIDER", "", "Provider for XDS auth")

	jwtPolicy = env.Register("JWT_POLICY", jwt.PolicyThirdParty,
		"The JWT validation policy.")
	// ProvCert is the environment controlling the use of pre-provisioned certs, for VMs.