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Quick Tip - Enabling ESXi Coredumps to be stored on USB

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I was recently working with Engineering to reproduce an issue which causes an ESXi PSOD (Purple Screen of Death) and I wanted the generated ESXi coredump to simply write to the USB device, which I could easily grab.

As of ESXi 7.x, I know we had removed a few of the old ESXi kernel boot options for allowing ESXi to store coredumps on a USB device and the using the ESXi kernel boot option allowCoreDumpOnUsb=TRUE should now be used, however I was struggling to get it to work.

Since I was using a debug version of ESXi, I needed to install ESXi from scratch and I thought I could simpply add the required kernel option, as shown in the screenshot below, and I had assumed it would automatically configure the ESXi coredump file to be stored on the VMFS-L volume residing on the USB device.


After a couple of attempts, I finally realized that this particular ESXi kernel boot option, is literally that, a boot option that is only applicable after the initial ESXi installation. 🤦 Unlike other ESXi kernel boot options which can be used during the initial installation which would apply certain configuration changes, this setting applies after ESXi has been installed. Once I appended the setting, the ESXi coredump file was created in the VMFS-L volume and I was then able to reproduce the issue and generate vm-support bundle that included the coredump!

Changing the default HTTP(s) Reverse Proxy Ports on ESXi 8.0

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The process of changing the default ports for the ESXi Reverse Proxy service has always been pretty straight forward, which I had also shared back in 2015 HERE. While most customers stick with the default configuration (80 for HTTP and 443 for HTTPS), we do have some customers that need to change these ports to meet certain organization security and/or compliance requirements.

Disclaimer: VMware does not officially support modifying the default HTTP/HTTPS ports on an ESXi host.

I recently came across a customer report where the previous method for changing the ESXi Reverse Proxy ports on an 8.0 host no longer worked and the only thing that was shared was that the user could no longer run ESXCLI directly within the ESXi Shell, which I thought was a strange observation.

I deployed the latest ESXi 8.0b as a Nested ESXi VM and I went through the instructions I had outlined in my blog post HERE and changed the HTTPS port from 443 to 4444, which was the setup the user was looking to do and I ran into the exact same issue. At first, I thought maybe we actually no longer support this capability and decided to quickly test by using the remote version of ESXCLI, which allows you to specify a port as part of the connection and it failed with the same error.

UPDATE (07/31/23) - For ESXi 8.0 Update 1 instructions, please refer to this blog post HERE.

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Automated ESXi Installation with a USB Network Adapter using Kickstart

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I have been working with the Project Keswick team for quite some time now, which is an OCTO project is lead by my good friend Alan Renouf, who is doing some really innovative work with ESXi at the edge and application deployment using a desired state engine.

Recently I had met with the team to discuss some of the options for their automated deployment which uses the tried and true ESXi scripted installation aka ESXi Kickstart. One thing that I had shared was just how powerful the %pre section within the kickstart is and can be used to redefine or update the original kickstart based on your installation criteria. For example, you could pull down external configuration files and determine at runtime to decide how you want to configure your networking to even fully bootstrapping a local vSAN datastore and this would all happen prior to ESXi installer starting. I have used the %pre section numerous times as a customer and also demonstrated in my USB-to-SDDC project which has also been an inspiration for the Project Keswick team.

One very cool capability that Project Keswick is enabling is the integration of the popular USB Network Native Driver for ESXi and one challenge they had faced with automating an ESXi installation when only a USB network adapter was available is additional configuration that must be setup before the installer can begin. They shared their solution and thought this would be a good blog post topic, especially as I know many folks use the USB Network Native Driver for ESXi in their homelab and if you wish to automate the installation, the solution shared from the team could help.

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