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UEFI PXE boot is possible in ESXi 6.0

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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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How to create custom ESXi boot menu to support multiple Kickstart files?

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I recently received a question from one of my readers who was looking to migrate from ESXi 4.1 to newer version and one of the challenges they faced was around their ESXi scripted installs, better known as ESXi Kickstart. Previously, they had relied on using a custom syslinux boot menu to be able to select a specific Kickstart configuration file that resided locally on a bootable ESXi Image (USB, ISO or CDROM) as a PXE/DHCP environment was not allowed in their environment. There was a small change to how ESXi boot files were reference between ESXi 4.x and ESXi 5.x/6.x and a new boot.cfg configuration is now used which I had written about here with respect to scripted installs when ESXi 5.0 was first released.

Luckily, even with these changes one can still use a custom menu with ESXi 5.x/6.x and be able to select a specific Kickstart configurations based on user input. Here is a screenshot example of a custom ESXi Image that I built providing three different install options that could be selected which would map to three different Kickstart configurations which can be either local to the boot media or can also be retrieved remotely.

bootable-esxi-image-with-multiple-kickstart-option
The first thing you should be aware of if you plan to boot the custom ESXi Image from local media such as USB, CDROM or ISO is that the path to the Kickstart file must be in all UPPER CASE which is mentioned in this VMware KB 1026373. The next caveat that I found in my testing is that if you plan to store the local Kickstart files inside of a directory within the ESXi Image, the name of the directory can not be too long. I would recommend using "ks" as "kickstart" apparently was too long.

After you have extracted the contents of an ESXi ISO which you have downloaded, you will want to create a root directory called "ks" which will contain the different Kickstart configuration files. Here is an example of what structure look like:

ks
├── ks1.cfg
├── ks2.cfg
└── ks3.cfg

Next, you will need to edit the isolinux.cfg file which comes by default within the ESXi ISO. This is where you will add the different Kickstart options that a user will be able to select from. In this first example, we will look at referencing the Kickstart files locally on the media which can be either USB or CDROM and you will need to ensure you specify the right boot option as shown here in the VMware documentation. The path to the Kickstart file needs to be appended to the line that contains boot.cfg reference and you must ensure you include "+++" at the end of that line.

Here is an example of referencing a Kickstart file that lives on a USB device under this path /ks/ks.cfg:

APPEND -c boot.cfg ks=usb:/KS/KS.CFG +++

Here is an example of my isolinux.cfg for the boot menu that I have shown above which provides three different options mapping to three different Kickstart configuration files:

DEFAULT menu.c32
MENU TITLE vGhetto Custom ESXi 6.0 Boot Menu
NOHALT 1
PROMPT 0
TIMEOUT 80
LABEL Ghetto Install
  KERNEL mboot.c32
  APPEND -c boot.cfg ks=cdrom:/KS/KS1.CFG +++
  MENU LABEL ^1 Ghetto Install
LABEL A bit More Ghetto Install
  KERNEL mboot.c32
  APPEND -c boot.cfg ks=cdrom:/KS/KS2.CFG +++
  MENU LABEL ^2 A bit More Ghetto Install
LABEL Super Ghetto ESXi Install
  KERNEL mboot.c32
  APPEND -c boot.cfg ks=cdrom:/KS/KS3.CFG +++
  MENU LABEL ^3 Super Ghetto ESXi Install
LABEL hddboot
  LOCALBOOT 0x80
  MENU LABEL ^Boot from local disk

As I mentioned earlier, the Kickstart configuration file can either be retrieved locally or it can also be retireved remotely using one of the following supported protocols: http, https, ftp & nfs as shown here in the VMware documentation.

Here is an example of isolinux.cfg for a boot menu which references both a local kickstart as well as one that remotely lives on a web server:

DEFAULT menu.c32
MENU TITLE vGhetto Custom ESXi 6.0 Boot Menu
NOHALT 1
PROMPT 0
TIMEOUT 80
LABEL Ghetto Install
  KERNEL mboot.c32
  APPEND -c boot.cfg ks=cdrom:/KS/KS1.CFG +++
  MENU LABEL ^1 Ghetto Install
LABEL A bit More Ghetto Install
  KERNEL mboot.c32
  APPEND -c boot.cfg ks=http://172.30.0.108/ks/ks2.cfg +++
  MENU LABEL ^2 A bit More Ghetto Install
LABEL Super Ghetto ESXi Install
  KERNEL mboot.c32
  APPEND -c boot.cfg ks=http://172.30.0.108/ks/ks3.cfg +++
  MENU LABEL ^3 Super Ghetto ESXi Install
LABEL hddboot
  LOCALBOOT 0x80
  MENU LABEL ^Boot from local disk

For additional ESXi Kickstart resources and example, be sure to check out my pages here.

Easily automate ESXi 6.0 Active Directory join using domainjoin-cli

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A nice little enhancement that I recently came across in ESXi 6.0 is the inclusion of the Likewise utility called domainjoin-cli which allows you to join a system to an Active Directory Domain. Previously, if you wanted to automate the process of joining an ESXi host to an Active Directory Domain, you had to either manually configure it using the vSphere Web/Client, using Host Profiles or creating an external script using the vSphere APIs.

All of these options were mostly executed during the post-provisioning process and if you wanted to include Active Directory configuration as part of the provisioning process, you may have had to resort to something like calling into the vSphere MOB within a Kickstart script as I had shown back in 2011 in this article here. The solution I came up with was not ideal but it worked for those that did not want to have additional steps after initial provisioning.

With the domainjoin-cli utility now included in the ESXi Shell of ESXi 6.0, you easily automate the joining an Active Directory Domain with just a couple of lines added to your Kickstart or provisioning scripts. Before you can use the command-line utility, you will need to ensure the Likewise Service Manager Daemon is running by running the following two commands which will start the service and also ensure the service automatically starts up:

/etc/init.d/lwsmd start
chkconfig lwsmd on

esxi6_active_domain_join_1
Next, to join to your Active Directory Domain, you will need to specify the following 3 parameters:

  1. join - Specifying the operation is a join versus a leave
  2. AD Domain Name - Active Directory Domain to join
  3. AD Username - Active Directory username to join to the domain
  4. AD Password - Active Directory password to join to the domain (optional as you will be prompted if it is not specified)

Here is an example of what the command looks like joining my Active Directory Domain in my lab:

/usr/lib/vmware/likewise/bin/domainjoin-cli join primp-industries.com administrator [PASSWORD]

esxi6_active_domain_join_2
You should see a success message if the ESXi host was successfully joined to the Active Directory Domain and you will want to reboot your ESXi host for the changes to take full effect. This is definitely a simpler method to include into an ESXi Kickstart script to automate the joining of an Active Directory Domain and hopefully you will find this handy when using ESXi 6.0.