vSphere Client service has stopped working with vCenter "503-Service Unavailable" Error due to ESXi Memory Exhaustion - Host Memory at 100% .

Products

• VMware vSphere ESX 8.x
• VMware vSphere ESXi 8.0

Issue/Introduction

You will notice below errors in the vCenter UI. 

You have no privileges to view this object or it is deleted.

You can use "Search Bar" to find the object you have access to.
No privileges to view this object or it is deleted image.

Example :

After restarting the vCenter Page you will notice the below banner with error "vSphere Client service has stopped working". 

VMware vSphere Client

i vSphere Client service has stopped working.
For troubleshooting refer Skyline Health Diagnostics.

Learn more by checking VMware vSphere Documentation and Support.

For appliance administration, navigate to vCenter Server Management appliance

Example :

After clicking vCenter Server Management appliance link you will notice 503 error

Few of the vCenter Services would be in stopped state. 

Example :

Stopped:
 vmcam vmonapi vmware-content-library vmware-hvc vmware-imagebuilder vmware-netdumper vmware-perfcharts vmware-rbd-watc
hdog vmware-sps vmware-trustmanagement vmware-vapi-endpoint vmware-vcha vmware-vsan-health vsphere-ui

 

When vCenter services are restarted it takes a long time to start and then fails to start few services. 

Environment

vCenter 8.x 

vCenter 9.x

ESXi 8.x 

ESXi 9.x

Cause

vCenter Server outage caused by a resource exhaustion loop. When the underlying ESXi host hits 100% memory utilization, the vCenter Server Appliance (VCSA) becomes unstable, leading to the "Service has stopped working" errors and the eventual 503 Service Unavailable page.

Resolution

Since the vCenter UI is inaccessible, you must manage this via the ESXi Command Line or the Direct Console User Interface (DCUI).

Step A: Free up Host Memory

You cannot fix the vCenter while the host is at 100% RAM.

1. Log directly into the ESXi Host Client (not vCenter) using the host's IP address.

2. Identify non-critical VMs and Power them Off to bring host memory usage down below 90%.

3. Ensure the vCenter VM has a Memory Reservation so the host doesn't throttle its RAM in the future.

Step B: Restart Services via SSH

Once the host has breathing room, log into the vCenter Server via SSH (using the root account):

1. Check Service Status: service-control --status

2. Attempt a Clean Start: service-control --start --all

Additional Information

High memory utilization alarms observed on ESXi hosts and cluster despite low active memory usage.

ESXi memory analysis using batch ESXTOP for high memory consumption troubleshooting