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VSAN Managed Object Browser (MOB) in vSphere 6.7 & vSphere 6.7 Update 1

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If you have ever spent any time using the vSphere API, you probably have heard of or have used the vSphere Managed Objected Browser (MOB) which is an extremely useful learning and debugging tool when working with the vSphere API. The vSphere MOB is accessed through a web browser connecting to either vCenter Server or ESXi and provides a graphical interface, allowing you to discovery/explore the underlying vSphere API and its data in a very intuitive manner.

As an avid user of the VSAN Management API since its release, I have always wanted something similar, especially when I first got started. I was quite happy when I found out in vSphere 6.7 and VSAN 6.7, the VSAN team has added a VSAN MOB interface directly on ESXi, for the VSAN specific APIs that are available only on an ESXi host. Just like the vSphere MOB which is also available on ESXi host, it is disabled by default and must be enabled.

The following ESXCLI commands can be used to enable/disable the VSAN MOB on ESXi 6.7:

esxcli vsan debug mob start
esxcli vsan debug mob stop

However, when I tried to enable the VSAN MOB, I ran into the following error message:

hostname 'localhost.localdomain' doesn't match '192.168.30.10'


It turns out there is an issue where it fails to match the IP Address of the ESXi host to the default localhost.localdomain and hence it fails to start the VSAN MOB. This issue is fixed in the upcoming vSphere & VSAN 6.7 Update 1, but in the mean time, there is a workaround.

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Automating vSphere Global Permissions with PowerCLI

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vSphere Global Permissions was first introduced in vSphere 6.0, which provides a simple and consistent method for assigning permissions for individual users and/or groups across multiple vCenter Servers joined to the same vCenter Single Sign-On (SSO) Domain. Global permissions works in the same way as traditional vSphere Permissions, but rather than assigning a permission to a specific entity, the association is applied at the root level of the vCenter Server.

The other added benefit for customers who are using vCenter's Enhanced Linked Mode (ELM), the global permission will be available to all vCenter Servers which are part of that ELM configuration. Without global permissions, a customer would have to create and assign a new permission to each and every vCenter Server and ensure that they all match which can be very error prone.

One downside to using vSphere Global Permissions today is that there is currently not a public API for those wanting to automate the creation and deletion of global permissions. However, as quick workaround, I have found a way in which you can automate the global permission management using the vSphere MOB which would allow us to use PowerCLI or any other vSphere Automation toolkit for that matter.

I have created a simple PowerShell script called GlobalPermissions.ps1 which contains two functions New-GlobalPermission and Remove-GlobalPermission which hopefully is self explanatory in what they do.

To create a new vSphere Global Permission, the function requires the following 6 parameters:

  • vc_server - Hostname or IP of the vCenter Server
  • vc_username - The VC username
  • vc_password - The VC password
  • vc_user - The vSphere User to assign the permission to
  • vc_role_id - The Role ID associated with the vSphere Role within vCenter Server (more on this later)
  • propagate - true or false on whether to propagate the permission

To retrieve the vc_role_id, you simply need access to a vCenter Server and run the following snippet along with the name of the vSphere Role to get its ID. In the example below, the Administrator role is called "Admin" using the vSphere API and the following will return the ID:

(Get-VIRole -Name Admin).ExtensionData.RoleId

Once you have retrieved the vSphere Role ID, here is an example of running the New-GlobalPermission function:

$vc_server = "192.168.1.51"
$vc_username = "*protected email*"
$vc_password = "VMware1!"
$vc_role_id = "-1"
$vc_user = "VGHETTO\lamw"
$propagate = "true"
New-GlobalPermission -vc_server $vc_server -vc_username $vc_username -vc_password $vc_password -vc_user $vc_user -vc_role_id $vc_role_id -propagate $propagate

If the operation was successful, you should be able to login using the vSphere Web Client and refresh the global permissions view and you should see the new permission assignment as shown in the screenshot below.

To remove a global permission, you only need to provide the vCenter Server, its credentials and the user permission you wish to remove:

Remove-GlobalPermission -vc_server $vc_server -vc_username $vc_username -vc_password $vc_password -vc_user $vc_user

How to automate vSphere MOB operations using PowerShell?

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A couple of weeks back I was investigating something that involved the use of the vSphere Managed Object Browser (MOB) and I needed to automate a particular operation. For those of you not familiar with the vSphere MOB, it is a UI debugging tool that allows you to visualize and invoke vSphere APIs using just a web browser. The vSphere MOB is available on both vCenter Server and ESXi and uses the underlying vSphere API. Outside of learning about the vSphere APIs and potentially for troubleshooting purposes, there really is no good reason to be directly interacting with the vSphere MOB on a regular basis. Customers can use any one of the many vSphere SDK/CLIs to easily automate and interact with the vSphere API.

Having said that, there may be cases where you might want to invoke a specific operation using the vSphere MOB, such as private API for example. Obviously, using any private/internal APIs is not officially supported by VMware and their use will be at your own risk. Nonetheless, I had a specific operation that I needed to call from the vSphere MOB and wanted to do so using PowerShell. Several years back I had demonstrated how you could invoke the vSphere MOB using Python but I could not find any PowerShell examples that actually worked. I figured this would be a good learning opportunity for myself and probably something I or others could benefit in the future.

To provide a concrete example, I will be invoking a supported vSphere API called the QueryOptions which is used for accessing either a vCenter Server or ESXi Advanced Settings. For our example, I will be connecting to the vCenter Server's MOB and will be querying for a specific vCenter Server Advanced Setting. If we were to do this manually in the vSphere MOB, we would first open a web browser and login to the following URL: https://[VC-SERVER]/mob/?moid=VpxSettings&method=queryView

automate-vsphere-mob-using-powercli
If you wanted to see all advanced settings, you would leave the "name" parameter blank. For our example, we will query for the VirtualCenter.InstanceName property as shown in the screenshot above and then click on the "Invoke Method" to execute the vSphere API operation. If successful, it should display the results which in our case is the IP Address of my vCenter Server. Pretty straight forward vSphere MOB example. OK, onto automating this from PowerShell. I have created a sample PowerShell script called automate-vsphere-mob.ps1 which you will need to edit and provide your vCenter Server Hostname/IP Address and the vCenter Server credentials (can be read-only) since we are not performing any write operations.

Here are some more specific details on what is happening in the script for those interested:

  1. Authenticate to the vSphere MOB URL that you wish to invoke using an HTTP GET operation and storing the session into a variable named vmware (Line 28-29)
  2. Extract the hidden vmware-session-nonce property used to prevent Cross-Site Request Forgery (CSRF) (Line 31-40)
  3. Create the body request which must include the vmware-session-nounce property along with the vSphere API payload (Line 42-45)
  4. Invoke the actual vSphere API call using an HTTP POST along with the existing session from Step 1 and body payload
  5. Process the results (this will be specific to API call) and profit! (Line 50-59)

If you now run the script, you will see that the result is exactly what we saw from interactively using the vSphere MOB. Hopefully this will be useful for anyone who may have a need to automate against the vSphere MOB. For those curious on what I was investigating with the vSphere MOB, stay tuned for more details 🙂