One or more of the ML internal indices could not be made hidden

One or more of the ML internal indices could not be made hidden – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 8-8.9

Briefly, this error occurs when Elasticsearch Machine Learning (ML) internal indices fail to convert to hidden indices. This could be due to insufficient permissions, a locked index, or a system error. To resolve this, ensure the user has the correct permissions to make changes to indices. If the index is locked, unlock it. If it’s a system error, restarting Elasticsearch may help. Also, consider upgrading Elasticsearch to the latest version as this issue might have been fixed in newer versions.

This guide will help you check for common problems that cause the log ” One or more of the ML internal indices could not be made hidden. ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: indices, plugin.

Log Context

Log “One or more of the ML internal indices could not be made hidden.” classname is MlInitializationService.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

        }; finalListener::onFailure);

        // Step 3: Once indices are hidden; fetch ML internal aliases to find out whether the aliases are hidden or not.
        ActionListener updateSettingsListener = ActionListener.wrap(updateSettingsResponse -> {
            if (updateSettingsResponse.isAcknowledged() == false) {
                logger.warn("One or more of the ML internal indices could not be made hidden.");
                return;
            }
            GetAliasesRequest getAliasesRequest = new GetAliasesRequest().indices(mlHiddenIndexPatterns)
                .indicesOptions(IndicesOptions.LENIENT_EXPAND_OPEN_CLOSED_HIDDEN);
            executeAsyncWithOrigin(client; ML_ORIGIN; GetAliasesAction.INSTANCE; getAliasesRequest; getAliasesResponseListener);