public void setChainName(String name) {
        chainName = name;
    }
Returns the name of the docproc cluster running indexing for this search cluster. This is derived from the
services file on initialization, this can NOT be used at runtime to determine indexing chain. When initialization
is done, the {@link #getServiceName()} method holds the actual indexing docproc chain object.

@return the name of the docproc cluster associated with this
config-model/src/main/java/com/yahoo/vespa/model/search/IndexingDocproc.java