Monitoring service is DOWN on NSX Manager and cluster is degraded when using small form factor

Products

• VMware NSX

Issue/Introduction

• NSX cluster status System> Appliances> Cluster Degraded is reported as degraded due to the Monitoring service not starting properly.
• The NSX Manager is small size form factor.
• The Monitoring service appears as "down" in the NSX UI or when checking cluster status via CLI using get cluster status.

• After rebooting the NSX manager the Monitoring service starts temporarily but stops again after a few minutes.
• The issue may be observed after upgrading from NSX 3.2.x to NSX 4.x or on a new deployment of NSX 4.x 
  • Deployed initially shows the Monitoring service as healthy.
  • Post-upgrade, the Monitoring service transitions to a down state and cluster status becomes degraded.
• On the NSX manager /var/log/syslog show the Monitoring service is down:
  • NSX 3945900 SYSTEM [nsx@6876 comp="nsx-manager" level="INFO" subcomp="upgrade-coordinator"] Services status is not up. MONITORING - DOWN, MESSAGING-MANAGER - UP
• /var/log/phonehome-coordinator/phonehome-coordinator-tomcat-wrapper.log shows Java heap space errors:
  • INFO   | jvm 8    | 2025/05/16 14:55:26 | java.lang.OutOfMemoryError: Java heap space
INFO   | jvm 8    | 2025/05/16 14:55:26 | Terminating due to java.lang.OutOfMemoryError: Java heap space
INFO   | jvm 9    | 2025/05/16 14:56:32 | java.lang.OutOfMemoryError: Java heap space
INFO   | jvm 9    | 2025/05/16 14:56:32 | Terminating due to java.lang.OutOfMemoryError: Java heap space
INFO   | jvm 10   | 2025/05/16 14:57:45 | java.lang.OutOfMemoryError: Java heap space 

Environment

VMware NSX 4.X

Cause

The Monitoring service fails to start due to Java heap space exhaustion, as indicated by the OutOfMemoryError messages in the logs. This can occur if the service is not allocated sufficient memory or if certain upgrade-related configurations are not correctly applied.

Resolution

This is known issue impacting VMware NSX.

This issue impacts only Small size form factor NSX Manager, 4 vCPU and 16GB Memory. As a workaround Medium size Manager should be used, 6 vCPU and 24GB Memory.