@Override
    public void allocatePorts(int start, PortAllocBridge from) {
        if (start == 0) {
            from.allocatePort("messaging");
            from.allocatePort("rpc");
            from.allocatePort("http");
        } else {
            from.wantPort(start++, "messaging");
            from.wantPort(start++, "rpc");
            from.wantPort(start++, "http");
        }
    }
Common class for config producers for storage and distributor nodes.
config-model/src/main/java/com/yahoo/vespa/model/content/ContentNode.java