public static ClusterMembership from(String stringValue, Version vespaVersion, Optional<DockerImage> dockerImageRepo) {
        return from(stringValue, vespaVersion, dockerImageRepo, ZoneEndpoint.defaultEndpoint);
    }
@Test
    void testContainerServiceInstance() {
        ClusterSpec cluster = ClusterSpec.request(ClusterSpec.Type.container, ClusterSpec.Id.from("id1")).vespaVersion("6.42").build();
        assertContainerService(ClusterMembership.from(cluster, 3));
    }