Unable to lock JVM Memory error= reason= – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch is unable to lock the JVM memory due to insufficient system settings or permissions. This can lead to swapping issues, affecting performance. To resolve this, ensure that the ‘bootstrap.memory_lock’ setting is true in the Elasticsearch configuration. Also, check the system’s limits.conf file to ensure that the ‘memlock’ limit is set to unlimited for the Elasticsearch user. If running in a Docker container, use the ‘ulimit’ command to increase the memory limit. Lastly, ensure Elasticsearch has the necessary permissions to lock memory.

This guide will help you check for common problems that cause the log ” Unable to lock JVM Memory: error={}; reason={} ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: bootstrap.

Log Context

Log “Unable to lock JVM Memory: error={}; reason={}” classname is JNANatives.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

            // this will have already been logged by CLibrary; no need to repeat it

        // mlockall failed for some reason
        logger.warn("Unable to lock JVM Memory: error={}; reason={}"; errno; errMsg);
        logger.warn("This can result in part of the JVM being swapped out.");
        if (errno == JNACLibrary.ENOMEM) {
            if (rlimitSuccess) {
                    "Increase RLIMIT_MEMLOCK; soft limit: {}; hard limit: {}";