How to fix Opensearch failed to start “java.lang.exceptionininitializererror: exception java.lang.unsatisfiedlinkerror” Error

If you’re running into the Opensearch failed to start error message caused by: java.lang.exceptionininitializererror:exception java.lang.unsatisfiedlinkerror: /tmp/opensearch-

when starting OpenSearch, you’re not alone. This error is usually triggered when Java tries to load a native (JNI) library, but fails due to missing files, incorrect permissions, or misconfigured environments. In this blog, we’ll walk through step-by-step fixes for resolving this startup issue and getting OpenSearch up and running smoothly.

Understanding the Error

At its core, the UnsatisfiedLinkError means Java is unable to load a native shared library. OpenSearch relies on such libraries — especially through Java Native Access (JNA) — to perform lower-level system operations. When this process fails, you’ll likely see a set of initialization errors during startup. The following are some things that you can check:

• Check if the file system permissions are correct.
• Ensure that /tmp is not mounted with the noexec flag; if it is, configure a custom directory for OpenSearch to execute temporary files.
• Check if the java installation and version is compatible to Opensearch

Step-by-Step Fixes

1. Check File System Permissions

Temporary directories like /tmp or /var/tmp are where JNA libraries are extracted during runtime. If OpenSearch doesn’t have proper permissions to execute files in these locations, it will throw an UnsatisfiedLinkError.

What to check:

• Does the OpenSearch user have execute permissions on /tmp, /var/tmp, or any other temporary directories?
  
• Are these directories mounted with the noexec flag?
  

How to fix:

You can view mount options using:

mount | grep /tmp

If you see noexec, you can remount with execution. Only do this if it aligns with your security policy.

mount -o remount, exec /tmp

2. Configure a Custom Temporary Directory (If noexec Is Required)

If you must keep /tmp mounted with noexec (common in hardened environments), you can point Java to a different, executable temp directory.

Steps:

Create a dedicated temp directory for OpenSearch:

sudo mkdir -p /opt/tmp/opensearch
sudo chown opensearch:opensearch /opt/tmp/opensearch
chmod 755 /opt/tmp/opensearch

Add this JVM option to your jvm.options or OpenSearch start script:

-Djava.io.tmpdir=/opt/tmp/opensearch

This tells Java to extract and run native libraries in that safe location.

3.  Verify Java Installation and JAVA_HOME

Ensure that a compatible Java Development Kit (JDK) or Java Runtime Environment (JRE) is installed and that the JAVA_HOME environment variable is correctly set and points to the root of your Java installation. 

java -version

If Java is missing or incompatible, install OpenJDK 17 (for Opensearch 2.x and higher):

sudo apt install openjdk-17-jdk   # Debian/Ubuntu
sudo yum install java-17-openjdk  # RHEL/CentOS

4. Check for Corrupted Installations or Upgrades (Optional)

If this issue appeared after upgrading OpenSearch or Java, there might be broken dependencies or missing files.

Fix:

• Backup your configuration and data

• Completely remove and reinstall OpenSearch.
• Restore your configurations and reindex if necessary.

Conclusion

The UnsatisfiedLinkError in OpenSearch is often caused by Java being unable to load native libraries due to permission issues, system hardening, or incompatible configurations. By checking file system permissions, configuring a custom temporary directory, verifying your Java setup, and reviewing logs, you can quickly diagnose and resolve the problem. Whether you’re running on a hardened server or a local development machine, these steps will help you get OpenSearch running smoothly again.

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