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

06.11.2015 by William Lam // 31 Comments

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.

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.

vCenter Server 6.0 Tidbits Part 11: Automate SSO Admin password change

06.09.2015 by William Lam // 1 Comment

After publishing my last article around the topic of Automating SSO Admin configurations using some simple LDAP commands which is applicable for both vSphere 5.5 and 6.0. It was pointed out to me by my buddy G. Blair Fritz who works over in our GSS Organization that another handy operation to share with customers is the ability to easily and quickly change an SSO Administrator password across multiple Platform Services Controllers (PSC). This is especially important for customers who have a password rotation policy set fourth by their Security team which most Enterprise customers have and are require to update their admin passwords every N-number of days.

Though you will not be able to query for an existing SSO Administrator's password (it is encrypted), you can however modify the password and this will require you to provide a valid SSO Administrator's account to connect with. To modify an LDAP entry, we will need to first create a file that contains the change, in the example here we are going to name it change.ldif and it should contain the following where the "replace" keyword shows which property is getting modified and the next line after shows the value that it will be changed to. Make sure to also replace the dc=vghetto with the name of your SSO Site Name

dn: cn=administrator,cn=users,dc=vghetto,dc=local
changetype: modify
replace: userpassword
userpassword: VMware1!

To apply the change, we will now run the following ldapmodify command and specifying our change.ldif configuration file:

/opt/likewise/bin/ldapmodify -f change.ldif -h 192.168.1.60 -D "cn=administrator,cn=users,dc=vghetto,dc=local" -w 'VMware1!!'

The really nice thing about this is that you can quickly change the password for your SSO Administrators across multiple Platform Services Controller and across multiple SSO Domains with a couple slight modifications to the command. How cool is that!? Thanks to Blair for sharing this awesome tidbit!

Quick Tip - Using ovftool to connect to vCloud Director behind a 2-Factor Authentication portal

06.08.2015 by William Lam // 2 Comments

A couple of months back I ran into an issue while trying to upload a couple of files to VMware's internal OneCloud environment which uses vCloud Director. The issue that I encountered was that our OneCloud environment no longer supported basic username/password authentication, which I hoping to automate using ovftool. Instead, it is now front-ended with VMware Application Manager which requires 2-Factor Authentication (2FA) and once authenticated, a SAML token is then passed to vCloud Director which then automatically logs you in.

The problem with this is that ovftool can not be used to directly login to vCloud Director as it does not have support for 2FA, which makes automating operations against our OneCloud environment pretty difficult. After spending a few days looking for an alternative and not having any luck, my last hope was to reach out to the ovftool developers to see if they had seen this before.

After a few email exchanges, although ovftool does not support 2FA, you can however get this to work using session ticket authetnication which it does support using either the --I:sourceSessionTicket or --l:targetSessionTicket option. To get more details on these options, you can run the following ovftool command:

ovftool --help integration

In order to use this session ticket mechanism to authenticate into a 2FA environment, you must first login manually using a web browser. Once you have successfully logged in, you will need to either use browser developer tool or something like Firebug to record the authenticated vCloud Director cookie which will then be passed to ovftool.

In this example, I am using Chrome and you can find the Developer Tools by going to Options->More Tools->Developer Tools. Next, refresh the webpage so you are able to see the web requests between your browser and vCloud Director. Now navigate to Network->Cookies option and select any one of the requests to the left of the screen such as "amf".

What you will be looking for is the value to the cookie named "vcloud_session_id" which is is the authenticated session that we will use to provide to ovftool. Once you have that value, you can then specify the connection to ovftool using the following:

ovftool --I:targetSessionTicket=[VCLOUD_SESSION_ID_VALUE] vcloud://...

I had known that ovftool supported session based tickets, however I did not realize it could be used to authenticate behind a 2FA solution like VMware Application Manager. For folks interested in using ovftool and session based tickets directly with vSphere, check out this awesome post by my good friend Jake Robinson who demonstrates this using PowerCLI, ovftool and the AcquireCloneTicket() vSphere API method.