WildFly Fails to Start After VNA Server Patch and Reboot

Products

• Network Observability

Issue/Introduction

After patching and rebooting the VNA server, the WildFly application server failed to start. Investigation revealed that the system was unable to detect Java 17, which is required by VNA. Executing the java -version command returned an error indicating that Java was not found.

Environment

DX NetOps Virtual Network Assurance 23.3.x/24.3.x

Cause

The issue was caused by an incorrect or missing Java installation path in the system's environment. As a result, the system could not locate the required Java 17 binary.

Resolution

1. Identify the Java Installation Path:

   Run the following command to locate the Java installation path:

   find / -name java

2. Create a Symbolic Link to the Java Binary:

   Use the identified Java path to create a symbolic link:

   ln -s <Java 17 path> /bin/java

3. Verify the Java Installation:

   Confirm the system recognizes Java by running:

   java -version

   The output should display the correct version of Java (Java 17 in this case).

4. Restart WildFly:

Start the WildFly application server. Ensure it launches successfully without errors.

systemctl start wildfly systemctl status wildfly

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Verification

• Confirm the server is operational and that WildFly is running without issues.
• Validate that the Java version is correctly recognized.

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Recommendations

• To simplify Java version management and avoid similar issues, use the update-alternatives command or maintain a permanent symbolic link to the correct Java binary.