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vSphere

Reset vSphere Appliance Root Password

To reset the root password when you don’t know it you have to reset it at the command line before boot.

Press “e” while booting to boot into the GRUB edit menu

Add the following to the end of the config line beginning with “linux”

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rw init=/bin/bash

Press F10 to reboot which will then boot into a bash shell as the root user.

Change the root password with:

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passwd

Then reboot:

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reboot -f

Sizing VMs

When choosing number of cpus per socket of VMs you want to pay attention to the processors of the host the vms are running on. You want to maximize the number of vNUMA nodes that are available to the VM. This is based on the architecture of the processors in the host.

By using the least cores per socket you will usually get the best performance.

Be careful as some applications can only use one socket, SQL servers can cause a problem here where you want more cores in the socket.

See here for detailed information https://blogs.vmware.com/vsphere/2013/10/does-corespersocket-affect-performance.html

Performance Monitoring

Monitor the vCenter appliance resources - you can use the VAMI or ssh into the vCenter appliance and use “vimtop”

Poor performance on vSphere Client or other services

poor performance can be caused by lack of memory. Check memory used by services with the following command:

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cloudvm-ram-size -J 

cloudvm-ram-size -J vsphere-ui

Change the heap size for a specific service:

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cloudvm-ram-size -C  

cloudvm-ram-size -C 700 vsphere-ui

Change Machine SSL cert

Change the machine ssl cert to allow browsers to trust the vsphere.

Generate a CSR then for windows CA create a template to produce a certificate. Then apply the certificate and certificate chain.

Certificate change process

Using a microsoft CA

Creating the certificate template

VM Customization

can customize vms with VM Customization Specifications.

If this fails on windows vms this could be due to the sysprep process failing if this is set in the VM Customization Specification.

To fix sysprep failing you may need to check the logs: $env:windir\system32\sysprep\panther\

if in the logs you see an issue with applications installed for a specific user you will need to uninstall them. Remove the package for all users:

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Get-AppxPackage #Find the package name
Remove-AppxPackage -Package 'SomeAppName_1.2.3.500_x64__8we4y23f8b4ws' AllUsers #Remove the package for all users

Regenerate certificate on vsphere appliances

regenerate certificates