private void setSearchClusterForLocalProvider(Map<String, ? extends SearchCluster> clusterIndexByName) {
        for (LocalProvider provider : localProviders()) {
            String clusterName = provider.getClusterName();
            SearchCluster cluster = clusterIndexByName.get(clusterName);
            if (cluster == null) {
                if (clusterName.contains(".")) { // Is there a super cluster ...
                    String prefix = clusterName.substring(0, clusterName.indexOf('.'));
                    cluster = clusterIndexByName.get(prefix);
                }
                if (cluster == null) {
                    throw new IllegalArgumentException("No searchable content cluster with id '" + provider.getClusterName() + "'");
                }
            }
            provider.setSearchCluster(cluster);
        }
    }
Root config producer of the whole search chains model (contains searchchains and searchers).

@author Tony Vaagenes
config-model/src/main/java/com/yahoo/vespa/model/container/search/searchchain/SearchChains.java