Cant send mapping refresh for ; no master known. – How to solve related issues

Opster Team

Jan-20, Version: 1.7-8.0

In addition to reading this guide, we recommend you run the Elasticsearch Template Optimizer to fix problems in your data modeling.

It will analyze your templates to detect issues and improve search performance, reduce indexing bottlenecks and optimize storage utilization. The Template Optimizer is free and requires no installation.

This guide will help you check for common problems that cause the log to appear. It’s important to understand the issues related to the log, so to get started, read the general overview on common issues and tips related to the Elasticsearch concepts below. Advanced users might want to skip right to the common problems section in each concept or run the template optimizer.

Log Context

Log “Can’t send mapping refresh for [{}]; no master known.” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

             NodeMappingRefreshRequest::new; ThreadPool.Names.SAME; new NodeMappingRefreshTransportHandler());

    public void nodeMappingRefresh(final DiscoveryNode masterNode; final NodeMappingRefreshRequest request) {
        if (masterNode == null) {
            logger.warn("can't send mapping refresh for [{}]; no master known."; request.index());
        transportService.sendRequest(masterNode; ACTION_NAME; request; EmptyTransportResponseHandler.INSTANCE_SAME);


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