VCP 5 – Objective 4.4 – Administer Virtual Machines and vApps

Identify files used by virtual machines

Files used by VMs are as follows
  • .vmx – Virtual machine configuration File
  • .vmxf – Additional VM Config File
  • .vmdk – Virtual disk characteristics
  • -flat.vmdk – preallocated virtual disk
  • .nvram – BIOS config
  • .vmsd – snapshot database
  • .vmsn – snapshot data file
  • .vswp – swap file
  • .vmss – VM suspend file
  • .log – log file
  • #.log – old log files.
Identify locations for virtual machine configuration files and virtual disks
By default when creating new disks for VMs it wants to store all the files in the same directory.  You can avoid this by using VM Storage Profiles which will use predetermined settings to place disks on the proper datastore.  Also, you can manually chose to change the location of a virtual disk.  By utilizing storage vMotion, you can separate disks and the vmx (config) file for the VM after they have been created.  Also, you can change locations of the swap files as explained in other sections of this study guide.
Identify common practices for securing virtual machines
  • Install Antivirus and stagger the scans to avoid contention.
  • Leave the default of copy/paste operations disabled.
  • Remove unnecessary Hardware devices
  • Limit guest OS system writes to host memory.
  • Configure VM Logging Levels
  • Secure FT logging network traffic
Hot Extend a virtual disk
Hot extending a virtual disk involves increasing the size of the disk within vSphere, then you need to go into the operating system itself and extend your partitions into the free space.  VMware has kb that recommends either using diskpart or adding the disk to another windows VM.
Configure virtual machine options
Virtual Machine options are as follows
  • General options
    • Modify VM Name
    • Check vmx location as well as working location.
    • Change Guest OS type (must be powered off).
  • vApp Options
    • Enable or disable vApp functionality.  When enabled, vApp options can be changed such as IP allocation policies.
  • VMware Tools
    • Manage power controls for the VM – VM must be powered off
      • Stop – Power Off, Shutdown Guest(default)
      • Pause – Suspend
      • Start (Power On/Resume)
      • Restart – Reset, Restart Guest (default)
    • Run VM Tools scripts(after power on, after resuming, before suspending, before shutting down guest).  VM must be powered off.
    • Can also check and upgrade VMware Tools during power cycling as well as synchronize guest time with the host.
  • Power management
    • How should VM respond when OS is placed in standby.  Options are to suspend the VM or put the guest OS into standby and leave VM powered on.
  • Advanced Options
  • General
    • Disable Acceleration – used to allow a VM to successfully run or install software.  Used if you see an issue which causes the VM to stop responding early in the execution of a program.  This setting actually slows down the VM.
    • Enable/Disable Logging
    • Debug Stats
      • Run Normal (default) – collects debug info
      • Record Debugging Information – collects debug and performance info.  Use to aid in troubleshooting when the guest OS is crashing frequently.
      • Record Statistics
    • Also some advanced configuration parameters
  • CPUID Mask – used to expose or hide nx/xd flags from the VM in order to increase vMotion compatibility.
  • Boot Options
    • Specify boot firmware (BIOS or EFI)
    • Power on Boot delay
    • Force into bios on next boot
    • Failed Boot Recovery – automatically retries a reboot if it fails.
  • Fibre Channel NPIV
    • Can enable/disable NPIV and assign and generate new WWNs for the VM.
    • allows you to share a physical hba port amongst multiple virtual ports in efforts to give the VM access to LUNs on a per VM basis.
    • Each virtual port is assigned a WWPN and a WWNN.
    • NPIV needs to be enabled on a SAN switch and supported only for VMs with RDMs.
    • Each VM can only have 4 NPIV WWNs.
  • CPU/MMU Virtualization
    • Allows you to override the hardware page table settings.
  • Swap File Location
    • Store with the VM
    • Store with the hosts swap file datastore.

Configure virtual machine power settings

Explained above.
Configure virtual machine boot options
Explained Above.
Configure virtual machine troubleshooting options
Explained above.
Assign a Storage Policy to a virtual machine
Storage Profiles list the storage capabilities that a VM's set of files and disks require in order to run the applications within the VM.  It's possible to create a list of VM storage profiles in order to define different levels of storage.  You then assign those storage profiles to both the VMs home files (.vmx, .vmsd, .nvram, .log) and the virtual disks (.vmdk).
Whenever a VM is created, cloned, or migrated you can select to associate it with a Storage Profile.  When you select the desired profile, the client will show you the list of datastores that are compatible with the capabilities of the selected profile.  You can then select the desired datastore or datastore cluster.
To associate a VM with a storage profile follow this process
  1. Right click the VM and select Edit Settings then navigate to the Profiles tab.
  2. Associate the VM home files with a storage profile from the Home VM storage profile menu.
  3. You can then either select to propagate that to the virtual disks, or associate each virtual disk with the VM Storage Profile menu.
Verify Storage Policy compliance for virtual machines
You can view the compliance of a VMs storage profile on the Summary tab of that VM in the VM Storage Profiles section.
Determine when an advanced virtual machine parameter is required
Virtual Machine advance parameters can be set in a couple of ways.  Either by using the Configuration Parameters button on Advanced Option settings of a VM or directly in the vmx file itself.  In either occurrence, the VM needs to be powered off to do so.  Most options that you need to perform are configurable without the use of advanced options and they should certainly be used sparingly and correctly by following specific VMware Knowledge base articles or through the direction of support.
Adjust virtual machine resources (shares, limits and reservations) based on virtual machine workloads
I've talked about this many times throughout these notes, so I'm not going to populate this area.

Leave a Reply

Your email address will not be published. Required fields are marked *