private void addDocproc(ContainerCluster<?> cluster) {
            if (cluster.getDocproc() == null) {
                DocprocChains chains = new DocprocChains(cluster, "docprocchains");
                ContainerDocproc containerDocproc = new ContainerDocproc(cluster, chains);
                cluster.setDocproc(containerDocproc);
            }
        }
Create a new container cluster for indexing and add it to the Vespa model
config-model/src/main/java/com/yahoo/vespa/model/content/Content.java