Unable to index the following ILM history items n – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 7.6-7.15

Briefly, this error occurs when Elasticsearch is unable to index the Index Lifecycle Management (ILM) history items due to issues like insufficient permissions, disk space, or network connectivity. To resolve this, you can check and increase the disk space if it’s low, ensure the user has the necessary permissions to index ILM history items, and verify the network connectivity. Also, check the Elasticsearch logs for more detailed error messages that can help identify the root cause.

This guide will help you check for common problems that cause the log ” unable to index the following ILM history items:\n{} ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index, plugin.

Log Context

Log “unable to index the following ILM history items:\n{}” classname is ILMHistoryStore.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

            new BulkProcessor.Listener() {
                public void beforeBulk(long executionId; BulkRequest request) {
                    if (clusterService.state().getMetadata().templatesV2().containsKey(ILM_TEMPLATE_NAME) == false) {
                        ElasticsearchException e = new ElasticsearchException("no ILM history template");
                        logger.warn(new ParameterizedMessage("unable to index the following ILM history items:\n{}";
                                .filter(dwr -> (dwr instanceof IndexRequest))
                                .map(dwr -> ((IndexRequest) dwr))