If you have used vMA's vi-fastpass authentication, you will know how easy it is to setup using vifp utility which supports both ESX/ESXi and vCenter targets.

[vi-admin@scofield ~]$ sudo vifp addserver esxi3-1.primp-industries.com
*protected email*'s password:

Here's an example of the listing of the available fastpass targets:

[vi-admin@scofield ~]$ sudo vifp listservers
esxi3-1.primp-industries.com ESXi

During this process, two accounts (vi-userXX & vi-adminXX) are created on the target host with a password that vMA management creates and caches it locally in an obfuscated but not encrypted form. This will allow you to initialize a fastpass target using vifpinit utility and execute commands against the target host without having to manually type in the credentials.

The fastpass targets are stored in 2 configuration files on vMA:

1) The obfuscated cached credentials is stored in /home/vi-admin/.vmware/credstore/vicredentials.xml

If you cat out the contents, it will look something like this:

   esxi3-1.primp-industries.com
   vi-admin00
   XXXXXXXXXXXXXXXXXXXXXXX

2) A More detailed configuration for each of the targets along is stored in /etc/vmware/viconfig/viconfig.xml

If you cat out the contents, it will look something like this:

   esxi3-1.primp-industries.com
   443
   524d18f6-8bbb-2c5f-a366-6d191813fbe3
   https
   /sdk
   vi-admin00
   vi-user00
   true
   ESX
   1276121961

What happens when you rebuild your host, or the system is no longer available because it has been decommissioned or being used for another purpose? vMA will still think it's managing the host and the fastpass credentials will no longer function as the account is no longer valid the host. If you try to remove the old target, you will see the following error:

[vi-admin@scofield ~]$ sudo vifp removeserver esxi3-1.primp-industries.com
*protected email*'s password:

Error: Failed to connect. Please make sure the server is up and is of supported version.

The reason this occurs is that vMA is unable to login to the host and remove the two accounts that were initially created and fails to remove the target. What you will need to do is actually pass in an additional parameter to vifp command "--force" which will forcefully remove the target from vMA management. This command actually does not require the user to enter the correct password to the host even if it is still reachable by vMA. By specifying this flag and providing some input when prompted for the password, vMA will purge the target from it is system.

[vi-admin@scofield ~]$ sudo vifp removeserver esxi3-1.primp-industries.com --force
*protected email*'s password:

After a target is removed from vMA, it is also removed from the two above files. You do not manually tweak either of these configuration files or it may lead to issues on your vMA host.

Best practice for decommissioning a host that has been added to vMA's management is the following:

1. Disable vilogger if you've enabled it for the host
2. Remove target from vMA management
3. Verify the host is no longer being managed by vMA
4. Decomission host