@Override
    public void validate() throws Exception {
        super.validate();
        if (search.usesHierarchicDistribution() && !isHosted) {
            // validate manually configured groups
            new IndexedHierarchicDistributionValidator(rootGroup, redundancy, search.getSearchCluster().getTuning().dispatch.getDispatchPolicy()).validate();
        }
        new ReservedDocumentTypeNameValidator().validate(documentDefinitions);
        new GlobalDistributionValidator().validate(documentDefinitions, globallyDistributedDocuments);
    }
Returns the distribution bits this cluster should use.
On Hosted Vespa this is hardcoded and not computed from the nodes because reducing the number of nodes is a common
operation, while reducing the number of distribution bits can lead to consistency problems.
This hardcoded value should work fine from 1-200 nodes. Those who have more will need to set this value
in config and not remove it again if they reduce the node count.
config-model/src/main/java/com/yahoo/vespa/model/content/cluster/ContentCluster.java