Real-time scenario-based questions and answers on VMware ESXi: Part-2

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6. ESXi Host Boots into “No Network Adapters Found” Error

Scenario:

After rebooting an ESXi host, you see the error “No Network Adapters Found” and cannot connect to the host via network.

Possible Causes:

  • NIC drivers are missing or incompatible.
  • ESXi version does not support the NIC hardware.
  • Network adapters are disabled in BIOS.
  • vSwitch or VLAN misconfiguration.

Solution Steps:

  1. Check BIOS Settings
    • Reboot the host and go into BIOS/UEFI.
    • Ensure onboard NICs are enabled.
  2. Check Physical NIC Connectivity
    • Try another network cable and switch port.
    • Use a USB NIC temporarily for management.
  3. Verify NIC Presence in ESXi CLI (DCUI or Direct Console)
    • Run: bashCopyEditesxcli network nic list
    • If no NICs are listed, drivers may be missing.
  4. Install or Reinstall NIC Drivers
    • Check VMware’s HCL (Hardware Compatibility List) for supported drivers.
    • Upload and install the correct VIB package for the NIC: bashCopyEditesxcli software vib install -v /vmfs/volumes/datastore/NIC-driver.vib
  5. Check for vSwitch or VLAN Misconfiguration
    • Go to vSphere Client → Configure → Networking.
    • Verify the correct VLAN ID and port group.
  6. Reinstall or Upgrade ESXi (If Necessary)
    • If drivers are not available, consider reinstalling ESXi with a compatible version.

7. Unable to Power On a VM – “Insufficient Resources” Error

Scenario:

A VM fails to power on with the error “Insufficient resources to satisfy the configured failover level”.

Possible Causes:

  • CPU/Memory is exhausted on the ESXi host.
  • HA (High Availability) settings prevent VM power-on.
  • VM is pinned to a specific host (Affinity Rules).

Solution Steps:

  1. Check Resource Utilization
    • Go to vSphere Client → Host → Monitor → Performance.
    • Check CPU/Memory usage.
  2. Check Admission Control (HA Settings)
    • If in an HA cluster, reduce HA failover capacity:
      • Go to vSphere Client → Cluster → Configure → HA.
      • Adjust Failover Capacity or disable Admission Control.
  3. Check vSphere DRS (Distributed Resource Scheduler)
    • If DRS is enabled, try migrating other VMs to free up resources.
  4. Verify VM Affinity Rules
    • Check if the VM is restricted to a specific host:
      • Compute Cluster → VM/Host Rules.
  5. Increase Host Resources (If Needed)
    • Add more RAM/CPU to the ESXi host or vMotion VMs to another host.

8. VM Stuck in “Powering Off” or “Powering On” State

Scenario:

A VM gets stuck during power operations and does not respond to normal commands.

Possible Causes:

  • VM process is stuck in the ESXi host.
  • Storage issues prevent proper shutdown.
  • vCenter lost sync with the ESXi host.

Solution Steps:

  1. Try to Power Off via vSphere Client
    • Right-click VM → Power Off.
    • If unresponsive, proceed to CLI.
  2. Find and Kill the VM Process Using CLI
    • SSH into the ESXi host.
    • Identify the stuck VM: bashCopyEditesxcli vm process list
    • Force kill the VM using the World ID: bashCopyEditesxcli vm process kill --type=force --world-id=<VM_ID>
  3. Restart Management Services (If Needed) bashCopyEdit/etc/init.d/hostd restart /etc/init.d/vpxa restart
  4. Check Storage Issues
    • If VM storage is inaccessible, verify the datastore status.
    • Use esxtop to check for high storage latency.

9. ESXi Host PSOD (Purple Screen of Death) – What to Do?

Scenario:

An ESXi host crashes with a Purple Screen of Death (PSOD), displaying an error message.

Possible Causes:

  • Hardware failure (RAM, CPU, NIC, HBA).
  • Driver or firmware compatibility issue.
  • Memory corruption or ESXi bug.

Solution Steps:

  1. Capture a Screenshot of the PSOD Message
    • Note the error code and module name.
  2. Reboot the Host and Check Logs
    • After reboot, check logs for details: bashCopyEditcat /var/log/vmkernel.log | grep -i "error"
  3. Verify Hardware Issues
    • Run hardware diagnostics via iLO (HP), iDRAC (Dell), or CIM monitoring.
    • Check server memory using Memtest.
  4. Update Drivers and Firmware
    • Check VMware HCL for the latest supported firmware/drivers.
    • Update using: bashCopyEditesxcli software vib update -d /vmfs/volumes/datastore/driver.vib
  5. Check for Known ESXi Bugs and Patch
    • Search VMware KB articles for known issues.
    • Apply the latest ESXi patches.

10. VM Disk Consolidation Needed – How to Fix It?

Scenario:

A VM shows “Virtual Machine Disks Consolidation Needed”, but the operation fails.

Possible Causes:

  • Snapshot file is locked.
  • Datastore is out of space.
  • VM is running on multiple snapshots.

Solution Steps:

  1. Try Manual Consolidation
    • Right-click VM → Snapshot → Consolidate.
  2. Check Snapshot Files Manually
    • SSH into ESXi and navigate to VM directory: bashCopyEditcd /vmfs/volumes/datastore/VM_Name ls -lh *.vmdk
  3. Remove Unused Snapshots
    • If the VM has multiple snapshots, delete old ones.
  4. Check for Locked Files
    • Run: bashCopyEditvmkfstools -D /vmfs/volumes/datastore/VM_Name/VM-flat.vmdk
    • If locked, check which host has the lock and restart it.
  5. Check Datastore Space
    • If low on space, free up storage before consolidating.
  6. Manually Remove Stale Snapshot Files bashCopyEditrm -rf VM-00000X-delta.vmdk

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