VMware ESXI troubleshooting guide


  • Troubleshooting Tools importance
  • ESXI Architecture
  • ESXI Architecture-Components
  • ESXI Log Files
  • EXSI Commands
  • HOW to Monitor & Configure ESXI Server Setting?
  • HOW to Monitor core ESXI Performance?
  • ESXI Troubleshooting-frequently used Commands
  • ESXI Configuration Files

Troubleshooting Tools importance

To improvise troubleshooting steps, we must Understand the ESXI Architecture from a component breakdown perspective.
Troubleshooting ESXI is very much the same as any operating system.
Start by narrowing down the component which is causing the problem
Key Learning Objective:
  • ESXI Architecture
  • ESXI Architecture Components
  • ESXI Log Files:which logs files to review and when
  • ESXI Commands: To isolate and troubleshoot issues
  • EXSI Configartion Files:Forms the backbone of troubleshooting sessions

ESXI Architecture

esxi host
ESXI Architecture Components
The ESXI architecture comprises the underlying operating system,called the VMkernel,and processes that run on top of it.
VMkernel provides a means for running all processes on the system,including management applications and agents as well as virtual machines.
It has control of all hardware devices on the server and manages resource for the applications.
The main processes that run on top of VMkernel are
  • Direct console user interface (DCUI)
  • Virtual Machine Monitor (VMM)
  • VMware Agents (hostdvpxa)
  • Common information Model (CIM) System
Direct Console User interface (DCUI)
  • Low-Level configuration and management interface,accessible through the console of the server used primarilly for initial basic configuration.
Virtual Machine Monitor (VMM)

Process that provides the execution environment for a virtual machine, as well as ahelper process known as VMX. Each running virtual machine has its own VMM and VMX Process.

VMware Agents (hostd and vpxa)

Used to enable high-level VMware infrastructure management from remote applications.

Common information Model (CIM)system

Interface that enables hardware-Level management from remote applications through a set of standard Apis.

ESXI Deep Dive-VMkernel

A POSIX-Like operating system developed by VMware which provides certain functionality like that found in other operating systems, such as process creation and control, signals, file system and process threads

  • Resource scheduling
  • i/o stacks
  • Device drivers
ESXI Deep Dive-File System
VMkernel uses a simple in-memory file system to hold the esxi server configuration files,log files,and staged patches
The file system structure is designed to be the same as that used in the service console of the traditional ESX server. for example
ESX Server configuration files are found in /etc/vmware
Log files are found in /var/log/vmware
Staged patches are uploaded to /tmp
This file system is independent of the vmware vSphere NMFS file system used to store virtual machines
The in-memory file system does not persist when the power is shout down.Therefore, log files do not survive a reboot if no scratch partition is configured
ESXI can configure a remot syslog server and remote dump server enabling us to save all log information on an external system
ESXI Deep Dive-User Worlds

The term user world refers to aprocess running in the VMkernel operating system. The environment in which a user world runs is limited compared to what is found in a general-purpose POSIX-compliant operating system such as Linux

  • The set of available signals is limited
  • The system API is a subset of POSIX
  • The/proc file system is very limited

A singale swap file is available for all user world processes. if a local disk exists, the swap file is created automatically in a small VFAT partion. otherwise the user is free to set up a swap file on one of the attached VMFS datastores.

Agents used by VMware to implement certain management capabilities have been ported from running in the service console to running in user words
The hosted process provides a programmatic interface to VMkernel and it is used by direct VMware vSphere client connections as well as apis. it the process that authenticates user and keeps track of which user and groups have privileges
The vpxa process is the agent used to connect to vCenter.it runs as a special system user called vpxuser.it acts as the intermediary between the hosted agent and vCenter server
The FDM agent used to provide vSphere High Avalibility capabilites has also been ported from runnung in the service console to running in its own user world
A Syslog daemon runs as a user world. if you enable remote logging that daemon forwards all log files to the remote target in addition to putting them in local files
Aprocess that handles the initial discovery of an iscsi target aftwer which point all iscsi traffic is handled by the VM kernel just as it handles any other device driver
esxi log
  • Dcui is the local user interface that is displayed only on the console of an esxi system
  • It provides a Bios-like menu-driven interface for interacting with the system its main purpose is initial configartion and troubleshooting
The DCUI configartion taks include
  • Set administrative password
  • Set Lockdown mode(if attached to VMware vCenter)
  • Configure and revert networking tasks
Troubleshooting tasks include
  • Perfrom simple network tests
  • view lo
  • restart agents
  • Restore defaults
Esxi Troubleshooting-Common files
log files
VMKsummary.log-Abrupt Host reboots
  • Time stamp indicating esxi server reboot.
  • VMkernel will always track Host reboots.
  • Disable the Automated Server Recovery feature from the bios to avoid automatic reboots.
Boot.gz log-slow boot issues
To troubleshoot booth slow boot and boot process hang of ESXI server.
Use DCUI-Alt+f12 to review VMkernel message during this time.
ESXI Troubleshooting-Commands

VMware vSphere ESXI shell which includes:

  • Esxcli commands
  • Aset of esxcg-*commands
  • A set of other commands for troubleshooting
How to Monitor & configure ESXI Server setting?
ESXI -Effective Commands for Troubleshooting
How to Monitor core ESXI performance?
Esxi Troubleshooting-frquently used commands
ESXI Troubleshooting-Configuration Files
ESXI-Effctive Commands for Troubleshooting
HOW to Monitor Core ESXI Performance?

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