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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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NFS Multi-Connections in vSphere 8.0 Update 1

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The upcoming vSphere 8.0 Update 1 release includes a lot of exciting new features, some of which you can learn about by listening to either The Unexplored Territory and VirtuallySpeaking Podcasts, both of which covered the vSphere 8.0 Update 1 launch announcement. One of the highlighted core storage platform feature is the long awaited NFS capability that will allows users to select and isolate a specific VMKernel interface as shown in the screenshot below.


This actually reminded me of another interesting NFS capability that will also be part of the upcoming vSphere 8.0 Update 1 release, which is for ESXi to support multiple TCP connections for a single NFS v3 volume, also referred to as nconnect for those familiar with this NFS capability.

For those interested in this new NFS capability, it is important to note that this setting will initially only be configurable by using either the vSphere API or ESXCLI directly on an ESXi host.

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