Cannot mlockall because JNA is not available – How to solve this OpenSearch error

Opster Team

Aug-23, Version: 1-2.9

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Briefly, this error occurs when the Java Native Access (JNA) library is not available or not properly installed in your OpenSearch environment. The mlockall function, which prevents the process memory from being swapped to disk, relies on JNA. To resolve this issue, ensure that the JNA library is correctly installed and accessible. If it’s not, you may need to download and install it. Also, check your OpenSearch configuration to ensure it’s correctly set to use JNA. Lastly, verify that your operating system permissions allow OpenSearch to use mlockall.

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This guide will help you check for common problems that cause the log ” cannot mlockall because JNA is not available ” to appear. To understand the issues related to this log, read the explanation below about the following OpenSearch concepts: bootstrap.

Log Context

Log “cannot mlockall because JNA is not available” classname is
We extracted the following from OpenSearch source code for those seeking an in-depth context :

        JNA_AVAILABLE = v;

    static void tryMlockall() {
        if (!JNA_AVAILABLE) {
            logger.warn("cannot mlockall because JNA is not available");


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