vCenter Server shows alarms "vsphere-ui status changed from green to yellow"

Products

• VMware vCenter Server

Issue/Introduction

• A "vSphere UI Health Alarm" has occurred indicating that vsphere-ui status has changed to yellow
• The vsphere_client_virgo.log in /var/log/vmware/vsphere-ui/logs contains the following errors:

  [YYYY-MM-DDTHH:mm:SS.SSSZ] [WARN ] health-status-73              com.vmware.vise.vim.cm.healthstatus.AppServerHealthService        Memory usage: used=566,946,048; max=629,669,888; percentage=90.03861528153621%. Status: YELLOW         
  [YYYY-MM-DDTHH:mm:SS.SSSZ] [INFO ] health-status-73              c.v.v.v.cm.HealthStatusRequestHandler$HealthStatusCollectorTask   Determined health status 'YELLOW: [(vmodl.LocalizableMessage) {
     dynamicType = null,
     dynamicProperty = null,
     key = webclient.memory.lowheap,
     arg = null,
     message = The server is running low on heap memory (>90% utilized.)
  }]' in 31 ms

Environment

VMware vCenter Server 8.x 

Cause

The heap memory utilization of the vsphere-ui service exceeds 90%

Resolution

Workaround:

• To workaround this issue, restart vsphere-ui service:
  service-control --restart vsphere-ui
  
  
• If the issue persists or occurred again, manually increase the vsphere-ui heap memory. For more information, see Manually increase the heap memory for vCenter services

Additional Information

• The memory consumption by vsphere-ui service depends on many factors like the size of vCenter Server, the scale of the inventory, how many and what kind of plugins are used, and so on.
  Although the initial heap sizes of each services are determined during system boot as cloudvm-ram-size -l shows, tuning may be required if the initial allocation does not fully meet the requirement of each environment.
  
  
  
• vCenter Server で "vsphere-ui status changed from green to yellow" というアラームが発生する。