ESXi – Page 109

UEFI PXE boot is possible in ESXi 6.0

10.09.2015 by William Lam // 21 Comments

A couple of days ago I received an interesting question from fellow colleague Paudie O'Riordan, who works over in our Storage and Availability Business Unit at VMware. He was helping a customer who was interested in PXE booting/installing ESXi using UEFI which is short for Unified Extensible Firmware Interface. Historically, we only had support for PXE booting/installing ESXi using the BIOS firmware. You also could boot an ESXi ISO using UEFI, but we did not have support for UEFI when it came to booting/installing ESXi over the network using PXE and other variants such as iPXE/gPXE.

For those of you who may not know, UEFI is meant to eventually replace the legacy BIOS firmware. There are many benefits with using UEFI over BIOS, a recent article that does a good job of explaining the differences can be found here. In doing some research and pinging a few of our ESXi experts internally, I found that UEFI PXE boot support is actually possible with ESXi 6.0. Not only is it possible to PXE boot/install ESXi 6.x using UEFI, but the changes in the EFI boot image are also backwards compatible, which means you could potentially PXE boot/install an older release of ESXi.

Note: Auto Deploy still requires legacy BIOS firmware, UEFI is not currently supported today. This is something we will be addressing in the future, so stay tuned.

Not having worked with ESXi and UEFI before, I thought this would be a great opportunity for me to give this a try in my homelab which would also allow me to document the process in case others were interested. For my PXE server, I am using CentOS 6.7 Minimal (64-Bit) which runs both the DHCP and TFTP services but you can use any distro that you are comfortable with.

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Erasing existing disk partitions now available in the vSphere Web Client (vSphere 6.0 Update 1)

09.29.2015 by William Lam // 9 Comments

One of the primary challenges when trying re-purpose existing storage devices is ensuring that all data and existing partitions have been completely removed. Often times, customers end up resorting to third-party tools like GParted which requires you to boot your server into the LiveCD before you can remove the existing partitions. This is less than ideal, especially if you need to perform this operation across multiple systems.

For customers who wish to re-purpose their existing storage devices for other use, including VSAN, there is now a new UI option in the vSphere Web Client introduced in vSphere 6.0 Update 1 to help assist with this procedure. I had not seen anyone talk about this feature yet and figure I would share some details as this is something I have heard customers ask for in the past. You can find this new option (icon with disk and eraser) by clicking onto a specific ESXi host and then selecting the Manage->Storage Adapters and then highlighting the specific storage device you wish to erase as seen in the screenshot below.

Once the erase partition icon or action is selected, you will then be presented with a summary of the existing partitions on the disk and then prompted to confirm that you wish to delete ALL partitions on the disk.

After the operation has successfully completed, you can now re-purpose the storage device for other use like VSAN!

For those of you who are interested from an Automation standpoint, this UI operation actually makes use of an existing vSphere API that has been for quite some time called updateDiskPartitions() under the StorageSystem manager of an ESXi host. To erase all partitions, you simply pass in an empty spec to the API method.

In addition, I also want to quickly mention that you will also have the ability to edit and erase existing disk partitions using the ESXi Embedded Host Client Fling which will be available in a future update. Below is a quick screenshot on what that would look like.

Override default VSAN Maintenance (decommission) Mode in VSAN 6.1

09.14.2015 by William Lam // Leave a Comment

Earlier this year, there was an interesting use case that was brought up from a customer regarding the use of vSphere Update Manager (VUM) and VSAN enabled ESXi hosts. Everything was working from a functional standpoint, but the customer wanted a way to control the default VSAN decommission mode which specifies how the data should be moved, if at all when a host is placed into maintenance mode. There are three supported options which includes Ensure Accessibility (default), Evacuate All Data and No Action. Depending on the customer and their use case, there may be valid reasons to use one or the other. For example, if I am shutting down my entire VSAN cluster for some hardware upgrade, I probably do not want any of my data to be migrated and the No Action setting would be acceptable. During an upgrade or patching an of ESXi host, some customers have expressed that they would prefer to leverage the Evacuate All Data setting which is perfectly fine, of course the maintenance mode would take long as all the dat must be migrated off the host first.

Prior to VSAN 6.1 (included in the vSphere 6.0 Update 1 release), it was not possible to override the default VSAN maintenance mode (decommission mode) option which defaults to Ensure Accessibility. This was a problem because if you decided you wanted to use a different option, there would be some manual intervention required from the user when using VUM. The workaround for the customer would be to either manually or using the vSphere API to automate the ESXi host maintenance mode operation and specify the decommission mode type before VUM would take over and update the host. Not an ideal solution but would work if you needed to override the default.

I thought this would be a nice feature enhancement to be able to override the default VSAN maintenance mode option which could vary from customer to customer depending on their use case. I got in touch with one of the VSAN Engineers to discuss the use case in more detail and he agreed that it would be useful to expose this type of a capability. In VSAN 6.1, there is now a new ESXi Advanced Setting called DefaultHostDecommissionMode which allows you to specify the default VSAN maintenance mode behavior.

Below is a table of the three available options (ensureAccessibility is default) that can be configured:

VSAN Decommission Mode Value	Description
ensureAccessibility	VSAN data reconfiguration should be performed to ensure storage object accessibility
evacuateAllData	VSAN data evacuation should be performed such that all storage object data is removed from the host
noAction	No special action should take place regarding VSAN data

This ESXi Advanced Setting can also be retrieved and configured using ESXCLI as well as the vSphere API.

To retrieve the current VSAN maintenance mode option using ESXCLI, run the following command:

esxcli system settings advanced list -o /VSAN/DefaultHostDecommissionMode

To configure the default VSAN maintenance mode option using ESXCLI, run the following command:

esxcli system settings advanced set -o /VSAN/DefaultHostDecommissionMode -s [DECOMISSION_MODE]