VNA not starting properly and the web UI REST page is unavailable

Products

• Virtual Network Assurance
• Network Observability
• CA Performance Management
• Spectrum

Issue/Introduction

After system reboots for OS patching, VNA is not starting properly.

We have the Spectrum integration disabled presently, but it's showing down in NetOps Portal, and the rest page is unavailable. 

I've tried stopping / restarting wildfly and mysql, as well as rebooting the system, but still a no go. 

The environment is our lab, though we need to determine whether its related to the OS patching prior to patching in production. 

After an in place OS upgrade on the VNA server, RH 7.x to RH 8.x, the VNA Gateway shows Operational Status Down in the Portal System Status VNA Gateway table. The same is seen in the VNA Administration page (Portal UI Administration -> Monitored Items Management -> VNA Administration.

• DX NetOps Virtual Network Assurance (VNA) Gateway shows Operational Status as Down.
• VNA web UI at VNA_HOST:8080 returns a 404 page not found error.
• The MySql and Wildfly services at the OS level start and remain running, but there are errors in the server.log.
  • The server.log for the VNA host shows this error at the end of it's startup cycle:

Sample server.log file error from a VNA 23.3.2 install whose OS was updated from RH 7 to 8. Post OS update when trying to start the environment this error appears.

2025-04-10 17:02:51,344 WARN  [org.jboss.modules.define] (MSC service thread 1-1) Failed to define class com.ca.em.sdn.gateway.broker.core.flow.FlowManager in Module "deployment.core-23.3.2-RELEASE.war" from Service Module Loader: java.lang.UnsupportedClassVersionError: Failed to link com/ca/em/sdn/gateway/broker/core/flow/FlowManager (Module "deployment.core-23.3.2-RELEASE.war" from Service Module Loader): com/ca/em/sdn/gateway/broker/core/flow/FlowManager has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0

Environment

All supported Network Observability DX NetOps Virtual Network Assurance releases

Cause

System patching cycle removed the required Java version for VNA, or set the systems Java release to an unsupported version.

Resolution

Install the Java version required by your VNA version. After ensuring the correct required Java version is set for use, restart the VNA Wildfly service.

What Java version is required for our VNA version? Review the System Requirements "Default JDK" section of the VNA Installation Requirements and Considerations documentation topic.

Additional Information

• What version of java is in use?
  • Run the command "which java" to determine the java executable used by the OS.
  • Run "<path> java -version" using the path output from the which command.
  • A common output from the which command is /bin/java. We'd then run "/bin/java -version".
• How to tell the system to use Java 11 vs Java 8 if both are installed?
  • For RH we'd use the alternatives command.
    • Running "alternatives --config java" will allow specification of the java version the system should use.
• Additional information can be found on the How to install Java 8 and 11 on Red Hat Enterprise Linux 8 page on the RedHat Developers website.