vLCM update for ESXi host update fails with message "Host cannot download files from VMware vSphere Lifecycle Manager patch store"

Products

• VMware vSphere ESXi

Issue/Introduction

• Users may experience failures when attempting to update ESXi hosts through vSphere Lifecycle Manager. The primary symptom is hosts being unable to download files from the patch store, often accompanied by error messages indicating download failures or service unavailability.
• The most common message from vLCM is "Host cannot download files from VMware vSphere Lifecycle Manager patch store"
• Common error messages to watch for:
  • "Cannot download files from VMware vSphere Lifecycle Manager patch store"
  • "MetadataDownloadError"
  • "HTTP Error 503 - Service Unavailable"

Environment

• VMware vSphere environments using Lifecycle Manager for host updates
• ESXi hosts managed by vCenter Server
• Environments where hosts and vCenter Server communicate across different network segments

Cause

This issue typically occurs due to one or more of the following conditions:

• Network connectivity issues between ESXi hosts and vCenter Server
• DNS resolution problems preventing proper host-to-vCenter communication
• Firewall configurations blocking required update traffic
• Network performance issues affecting large file transfers
• Missing or incorrect port configurations

Resolution

1. Verify Network Connectivity
   1. Test basic connectivity between ESXi host and vCenter Server using netcat:
      • nc -zv <vcenter_ip> 80
      • nc -zv <vcenter_ip> 443
      • nc -zv <vcenter_ip> 902
      • nc -zv <vcenter_ip> 9084
        
        
2. Check DNS Resolution
   1. Verify DNS resolution of vCenter FQDN from the ESXi host
   2. If needed, add vCenter FQDN to the host's `/etc/hosts` file
      
      
3. Configure Firewall Rules
   1. Ensure required ports (80, 443, 902, 9084) are open between hosts and vCenter
   2. Verify no SSL inspection is interfering with update traffic
      
      
4. Review Network Performance
   1. Check Basic Network Status
      • Run esxcli network nic list to verify NIC status and speed
      • Use esxcli network vm list to check VMkernel interface configuration
      • Verify MTU settings match across the network path
   2. Monitor Network Performance with esxtop
      • Enter esxtop by running esxtop` in the ESXi shell
      • Press 'n' to switch to network view
      • Key metrics to monitor:
        • %DRPTX and %DRPRX (% of dropped packets)
        • MbTX/s and MbRX/s (throughput)
        • USED-pct (network utilization)
      • Press 'f' to customize fields, ensure these columns are visible:
        • Press 'j' for %DRPTX
        • Press 'k' for %DRPRX
        • Press 'l' for MbTX/s
        • Press 'm' for MbRX/s
   3. Perform Network Performance Testing
   4. Collect Network Traces for Analysis
      • On ESXi host
        • pktcap-uw --vmk vmk0 --dir 2 -o /tmp/capture.pcap
        • Monitor for:
          • Excessive retransmissions
          • High latency in responses
          • Connection resets
          • Packet fragmentation issues
   5. Review Network Resource Allocation
      • Check for resource pool constraints
      • Verify QoS settings aren't limiting update traffic
      • Monitor CPU usage during transfers:
        • On ESXi host
          • esxtop -b -n 10 -d 5 > esxtop_output.txt
            
            
5. Document Performance Findings
   1. Record baseline performance metrics:
      • Normal network latency
      • Expected throughput
      • Typical packet loss rates
   2. Compare against observed metrics during update operations
   3. Document any deviations from baseline
      
      
6. Apply Performance Optimizations
   1. If packet loss is detected:
      • Consider adjusting VMkernel buffer sizes
      • Review network QoS settings
   2. For bandwidth constraints:
      • Schedule updates during low-traffic periods
      • Consider implementing traffic shaping
   3. For latency issues:
      • Verify routing efficiency
      • Check for network congestion points
        
        
7. Clear and Reset Update Process
   1. Clear the Lifecycle Manager database if necessary
   2. Perform a new compliance scan
   3. Monitor logs for successful downloads
      
      
8. - For environments with low bandwidth (<5 Mbps), consider staging updates during off-peak hours

Additional Information

• Normal network performance baselines:

  • Expected throughput: >100 Mbps for LAN environments

  • Acceptable packet loss: <0.1%

  • Maximum latency: <5ms within same datacenter

• Common performance bottlenecks:

  • Network interface configuration mismatches

  • Oversubscribed uplinks

  • Resource contention with other services